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Question 1
Incorrect
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A 67 year old man reports weight loss. Labs show a raised alkaline phosphatase at 290 U/L (normal range 35-120). Plain radiographs reveal sclerotic lesions of the bone. Which of the following is the most likely cause of these findings?
Your Answer: Osteomalacia
Correct Answer: Prostate cancer
Explanation:Osteoblastic (or sclerotic) bony metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma. The other cancers listed in the options are osteolytic.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 2
Incorrect
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Which one of the following features is least associated with primary hyperparathyroidism?
Your Answer: Depression
Correct Answer: Sensory loss
Explanation:The signs and symptoms of primary hyperparathyroidism are those of hypercalcemia. They are classically summarized by stones, bones, abdominal groans, thrones and psychiatric overtones.
Stones refers to kidney stones, nephrocalcinosis, and diabetes insipidus (polyuria and polydipsia). These can ultimately lead to renal failure.
Bones refers to bone-related complications: osteitis fibrosa cystica, osteoporosis, osteomalacia, and arthritis.
Abdominal groans refers to gastrointestinal symptoms of constipation, indigestion, nausea and vomiting. Hypercalcemia can lead to peptic ulcers and acute pancreatitis.
Thrones refers to polyuria and constipation
Psychiatric overtones refers to effects on the central nervous system. Symptoms include lethargy, fatigue, depression, memory loss, psychosis, ataxia, delirium, and coma.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 3
Correct
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The production of bile is increased by: Stimulation of the ____ nerve and the hormone ____.
Your Answer: Vagus, CCK
Explanation:Cholecystokinin is synthesized and secreted by enteroendocrine cells in the duodenum, the first segment of the small intestine, and causes the release of digestive enzymes and bile from the pancreas and gallbladder, respectively. It also acts as a hunger suppressant. Release of CCK is stimulated by monitor peptide released by pancreatic acinar cells as well as CCK-releasing protein, a paracrine factor secreted by enterocytes in the gastrointestinal mucosa. In addition, release of acetylcholine by the parasympathetic nerve fibers of the vagus nerve also stimulate its secretion.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 4
Correct
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With regards to the cell cycle, which phase represents period of cell growth that divides the end of DNA synthesis and the beginning of somatic cell division?
Your Answer: Gap 2
Explanation:Interphase is divided into three phases: G1 (first gap), S (synthesis), and G2 (second gap). During all three parts of interphase, the cell grows by producing proteins and cytoplasmic organelles. However, chromosomes are replicated only during the S phase. Thus, a cell grows (G1), continues to grow as it duplicates its chromosomes (S), grows more and prepares for mitosis (G2), and finally divides (M) before restarting the cycle.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 5
Incorrect
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What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer: Secrete renin.
Correct Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 6
Correct
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Humoral immunity is a major defence against:
Your Answer: Viral infections
Explanation:Humoral immunity is provided by the neutralizing and non-neutralizing antibodies that are formed from the B lymphocytes. This form of immunity is most important in viral infection. Non-neutralizing antibodies increases phagocytosis of the infected cell and inhibit the ability of the virus to replicate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 7
Incorrect
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A 75 year old man presented to hospital after suffering a stroke. The doctor admitted him and advised of the Barthel score index. During rehabilitation, which one of the following limitations are best described by Barthel score index?
Your Answer: It has poor concurrent and predictive validity
Correct Answer: Floor and ceiling effects
Explanation:Barthel scoring has floor and ceiling effects which is the most widely recognised limitation. Floor effect means that the patient who is bed bound can score initially low, whereas the ceiling effect shows that despite being bed bound, a patient can achieve a maximum score i.e. 100. The test is easy to perform and correlates well with other prognostic scales.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 8
Correct
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Almost all of the protein that appears in the stool is:
Your Answer: Comes from bacteria and cellular debris
Explanation:75% of faecal weight is water. By dry weight 30% of faeces is bacteria,10-20% is fat and 2-3% proteins. Almost all proteins ingested are absorbed in the gut.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 9
Incorrect
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The onset of puberty is triggered by
Your Answer: Increased conversion of androstenedione to estrone by aromatase (females)
Correct Answer: Increase in pulsatile GNRH secretion from hypothalamus
Explanation:The onset of puberty is associated with high GNRH pulsing, which precedes the rise in sex hormones. Brain tumours which increase GNRH output may also lead to premature puberty. The cause of the GNRH rise is unknown.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 10
Correct
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Which of the following features occurs very less frequently with drug induced lupus?
Your Answer: Glomerulonephritis
Explanation:Drug induced lupus typically presents with pulmonary involvement and no renal or neurological involvement. Hence glomerulonephritis would be highly unlikely in this case. Rash and arthralgias are classic presentations. Pleurisy can be present as pulmonary involvement may occur with DILE.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 11
Correct
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Question 12
Correct
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Which of the following conditions is associated with eosinophilia?
Your Answer: Ascaris
Explanation:Eosinophilia can be idiopathic (primary) or, more commonly, secondary to another disease. In the Western World, allergic or atopic diseases are the most common causes, especially those of the respiratory or integumentary systems. In the developing world, parasites are the most common cause e.g. Ascaris
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This question is part of the following fields:
- Haematology
- Medicine
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Question 13
Incorrect
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In which phase do chromosomes in the nucleus become completely condensed into well-defined chromosomes?
Your Answer: Telophase
Correct Answer: Metaphase
Explanation:Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate
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This question is part of the following fields:
- Genetics
- Medicine
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Question 14
Correct
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What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Correct
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During which stage does the mitotic apparatus dissolute?
Your Answer: Telophase
Explanation:In telophase the nuclear envelope along with the nucleolus will reappear. The daughter nuclei will enlarge as the chromosome will decondense again. Along with this, cytokinesis will occur. At the end of cytokinesis the daughter centrioles will move from the poles to the intercellular bridge where they will be disassembled and complete the separation of the daughter cells
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This question is part of the following fields:
- Genetics
- Medicine
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Question 16
Correct
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Efferent innervation of the muscle spindle is supplied by which type of motor neuron?
Your Answer: Gama – motor neuron
Explanation:The muscle spindle is supplied by both sensory and motor nerves. Sensory supply is via Type Ia fibers whereas the motor supply is via gamma motor neurons.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 17
Incorrect
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A 62-year-old software developer with lung cancer is currently taking MST 30mg bd for pain relief. What dose of oral morphine solution should he be prescribed for breakthrough pain?
Your Answer: 15 mg
Correct Answer: 10 mg
Explanation:The total daily morphine dose is 30 x 2 = 60 mg. Therefore, the breakthrough dose should be one-sixth of this, 10 mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 18
Correct
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Question 19
Incorrect
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Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through:
Your Answer: Inhibiting tumour suppressor genes.
Correct Answer: Point mutations in genomic DNA
Explanation:80% of the pancreatic cancers are environmentally influenced by smoking which increases the risk by 50%. Mutation can occur in the KRAS, p16, SMAD4, and TP53 genes among other tumour suppression genes. Smoking can be implicated in transformation of all these genes. Apart from KRAS all the genes are inactivated in pancreatic cancer. As KRAS is the most commonly altered gene, mutation occurs as point mutation. As smoking is the most common aetiology in pancreatic cancer, and KRAS is the most important gene that is altered. Most commonly cigarette smoke causes point mutation.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 20
Incorrect
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Regarding carbohydrates absorption;
Your Answer: Insulin greatly increase intestinal transport of sugars
Correct Answer: Intestinal absorption of sugars is inhibited by the drug phlorizin
Explanation:The main role of insulin is in the uptake of glucose from blood to tissues where it is metabolised. Glycose transporters in the intestines do not depend on the action of insulin. Phlorizin is a competitive inhibitor of SGLT1 and SGLT2 because it competes with glucose for the binding site, reducing intestinal and renal glucose transport.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Correct
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Question 22
Incorrect
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A 42 year old female presents with a funny bone sensation in her right elbow that is accompanied by numbness and tingling in the 4th and 5th digits. The symptoms are aggravated when the elbow is bent for a prolonged period. Which of the following explains the most likely diagnosis?
Your Answer: Medial epicondylitis
Correct Answer: Cubital tunnel syndrome
Explanation:Cubital Tunnel Syndrome is a condition that involves pressure or stretching of the ulnar nerve (also known as the “funny bone” nerve), which can cause numbness or tingling in the 4th and 5th digit, pain in the forearm, and/or weakness in the hand. Epicondylitis of the elbow is a condition associated with repetitive forearm and elbow activities. Both lateral epicondylitis (commonly known as tennis elbow) and medial epicondylitis (commonly known as golfer’s elbow) are characterized by elbow pain during or following elbow flexion and extension. Radial tunnel syndrome is a set of symptoms that include fatigue or a dull, aching pain at the top of the forearm with use. Although less common, symptoms can also occur at the back of the hand or wrist.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 23
Incorrect
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Which among the following antihypertensives is centrally acting?
Your Answer: Phenoxybenzamine
Correct Answer: Moxonidine
Explanation:Moxonidine and alpha-methyl dopa are centrally acting antihypertensives and modify blood pressure through modifying sympathetic activity.Other options:Verapamil is a calcium antagonist.Minoxidil and hydralazine are both vasodilators.Phenoxybenzamine is an alpha-blocker.Adverse effects:Dry mouth and somnolence were the most frequently reported adverse events, followed by headache, dizziness, nausea and allergic skin reactions.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 24
Correct
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Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 25
Incorrect
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What is the most common cardiac defect seen in patients with Down’s syndrome?
Your Answer: Ventricular septal defect
Correct Answer: Atrioventricular septal defect
Explanation:The rate of congenital heart disease in new-borns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrioventricular septal defect or ventricular septal defect with the former being more common. Mitral valve problems become common as people age, even in those without heart problems at birth.[3] Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus.[38] People with Down syndrome have a lower risk of hardening of the arteries
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Incorrect
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In the absence of insulin:
Your Answer: Intestinal absorption of glucose is reduced
Correct Answer: Glucose uptake by most of the brain is normal
Explanation:Although it is known that insulin levels affect glucose uptake, oxidation and storage in peripheral tissues, its role in the brain isn’t as clear. However, studies have shown that bulk brain glucose uptake isn’t affected by insulin. Glucose transport into the neurons is GLUT3 dependent, and its transport into glia and brain endothelial cells rely on GLUT1. Insulin isn’t necessary for GLUT1 or GLUT3, which explains why brain glucose uptake isn’t affected by insulin levels.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 27
Incorrect
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Where is the majority of Mg2+ absorbed?
Your Answer:
Correct Answer: Thick ascending limb of loop of Henle.
Explanation:Although the majority of the filtered magnesium is reabsorbed within the ascending loop of Henle, it is now recognized that the distal tubule also plays an important role in magnesium conservation.
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This question is part of the following fields:
- Medicine
- Renal
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Question 28
Incorrect
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Which of the following statements is true of the beta- lactams:
Your Answer:
Correct Answer: Co-amoxiclav is more likely to cause obstructive jaundice than amoxicillin
Explanation:β-lactam antibiotics are a class of broad-spectrum antibiotics, consisting of all antibiotic agents that contain a β-lactam ring in their molecular structures. This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring. To overcome this resistance, β-lactam antibiotics are often given with β-lactamase inhibitors such as clavulanic acid. Immunologically mediated adverse reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions). Rarely, cholestatic jaundice has been associated with Co-amoxiclav (amoxicillin/clavulanic acid). The reaction may occur up to several weeks after treatment has stopped, and usually takes weeks to resolve. It is more frequent in men, older people, and those who have taken long courses of treatment; the estimated overall incidence is one in 100,000 exposures.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 29
Incorrect
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Which statement describes endogenous transmission the best?
Your Answer:
Correct Answer: Commensal flora that gain access to an inappropriate area
Explanation:All answers A, B, C, and D are examples of exogenous infections. Endogenous infection is an infection by organisms that normally reside in the body but have previously been dormant.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 30
Incorrect
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Which statement is incorrect regarding transcription of DNA?
Your Answer:
Correct Answer: A gene is always read in the 3’-5’ orientation and at 3’ promoter sites.
Explanation:In both prokaryotes and eukaryotes RNA polymerase acts in the 5′-3′ direction and hence the RNA is transcribed in this direction. The mRNA produced is immature as it has introns as well as exons presents. It undergoes a process known as splicing to remove the exons and then interacts with the ribosomes to form proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 31
Incorrect
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What is a characteristic findings on ECG in hyperkalaemia?
Your Answer:
Correct Answer: Tall, tented T waves
Explanation:Hyperkalaemia leads to:
– Prolonged PR interval
– Small P waves
– Tall, tented T waves
– Widened QRS complexes and eventually asystole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 32
Incorrect
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Which one of the following statements best describes a type II statistical error?
Your Answer:
Correct Answer: The null hypothesis is accepted when it is false
Explanation:In statistical hypothesis testing there are 2 types of errors:- type I: the null hypothesis is rejected when it is true – i.e. Showing a difference between two groups when it doesn’t exist, a false positive. – type II: the null hypothesis is accepted when it is false – i.e. Failing to spot a difference when one really exists, a false negative.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 33
Incorrect
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The thalamus is a large collection of neuronal groups within the diencephalons which participates in:
Your Answer:
Correct Answer: Sensory, motor and limbic
Explanation:The thalamus has multiple functions. It is the relay station for every sensory system (except olfactory, regulates the sleep-wake cycle and consciousness and also relays motor information.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 34
Incorrect
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Which of the following involving the scalp may produce alopecia (hair loss)?
Your Answer:
Correct Answer: Discoid lupus erythematosus
Explanation:Causes of hair loss include:
- Dissecting cellulitis
- Fungal infections (such as tinea capitis)
- Folliculitis
- Secondary syphilis
- Demodex folliculorum
- Lupus erythematosus (hair loss may be permanent due to scarring of the hair follicles).
Psoriasis and seborrheic dermatitis commonly involve the scalp but do not produce hair loss.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 35
Incorrect
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A 47-year-old woman diagnosed with oestrogen receptor positive breast cancer three months ago was started on treatment with tamoxifen. Which of the following is most likely a complaint of this patient during her review today?
Your Answer:
Correct Answer: Hot flushes
Explanation:The most likely complaint of this patient would be hot flushes.
Alopecia and cataracts are listed as possible side-effects, however they are not as prevalent as hot flushes, which are very common in pre-menopausal women.
Tamoxifen is a Selective Oestrogen Receptor Modulator (SERM) which acts as an oestrogen receptor antagonist and partial agonist. It is used in the management of oestrogen receptor-positive breast cancer
Adverse effects:
- Menstrual disturbance: vaginal bleeding, amenorrhoea
- Hot flushes – 3% of patients stop taking tamoxifen due to climacteric side-effects.
- Venous thromboembolism.
- Endometrial cancer (although antagonistic with respects to breast tissue, tamoxifen may serve as an agonist at other sites. Therefore the risk of endometrial cancer is increased). Raloxifene is a pure oestrogen receptor antagonist and carries a lower risk of endometrial cancer.
Tamoxifen is typically used for 5 years following the removal of the tumour.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 36
Incorrect
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Question 37
Incorrect
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Immortality can result from over expression of which enzyme?
Your Answer:
Correct Answer: Telomerase
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 38
Incorrect
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The pontine tegmentum as part of the midbrain, contains which cranial nerve nuclei?
Your Answer:
Correct Answer: CN 5 to 8
Explanation:The pontine tegmentum also known as dorsal pons is located within the brain stem. Several cranial nerve nuclei are located in the pontine tegmentum. The nuclei of CN V, CN VI, CN VII and CNVIII are located in the pontine tegmentum.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 39
Incorrect
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The majority striatal neurons, called medium spiny neurons, utilizes which neurotransmitter?
Your Answer:
Correct Answer: GABA
Explanation:Medium spiny neurons are inhibitory neurons which use GABA (gamma-aminobutyric acid) which exerts inhibitory actions. These cells represent 95% of neurones within the human striatum found in basal ganglia.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 40
Incorrect
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Which of the following enzymes is mainly responsible for the hydrolysis of polysaccharide 1:6a linkages?
Your Answer:
Correct Answer: Isomaltase
Explanation:Isomaltase is mainly responsible for hydrolysis of 1:6α linkages. Along with maltase and sucrase, it also breaks down maltotriose and maltose.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 41
Incorrect
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Salty taste is triggered by:
Your Answer:
Correct Answer: Amiloride-sensitive sodium channel
Explanation:Amiloride-sensitive sodium channels also known as epithelial Na channels is a membrane bound ion channel that is selectively permeable to Na+ ions. These channels are located throughout different epithelial membranes in the body. It is found in taste receptor cells, where it plays an important role in salt taste perception. They are also located in the kidney, the lung and the colon. Hyperpolarization-activated, cyclic nucleotide-gated (HCN) voltage-gated ion channels are widely seen in the cortex, hippocampus, thalamus and brain regions that underlie the generation of both focal and generalized-onset seizures. The metabotropic glutamate receptor (mGluRs) perform a variety of functions in the central and peripheral nervous systems. They are involved in learning, memory, anxiety, and the perception of pain. Gustducin is a G protein associated with taste and gustatory system. It plays a major role in sensation of bitter, sweet and umami stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 42
Incorrect
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Which enzyme deficiency causes Beriberi?
Your Answer:
Correct Answer: Thiamine
Explanation:Beriberi refers to a cluster of symptoms caused primarily by thiamine (vitamin B1) deficiency. Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 43
Incorrect
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Where is Müllerian inhibiting substance (MIS) secreted?
Your Answer:
Correct Answer: Sertoli cells
Explanation:Müllerian inhibiting substance, also known as Anti-Müllerian hormone (AMH) or Müllerian-inhibiting hormone (MIH) is a glycoprotein hormone which prevents the development of the Müllerian ducts into the uterus. Its production by Sertoli cells continues during childhood in males and decreases after puberty.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 44
Incorrect
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A 22-year-old female is brought to the emergency department by her friends following the consumption of an unknown drug whilst clubbing. Which of the following features point towards the use of ecstasy?
Your Answer:
Correct Answer: Temperature of 39.5ºC
Explanation:Hyperthermia (Temperature 39.5 C) points towards the use of ecstasy.MDMA (3,4 – methylenedioxymethamphetamine), or more commonly known as Molly or Ecstasy, is a synthetic psychoactive substance.Patients who consumed MDMA may present in a tachycardic, hypertensive, hyperthermic, and agitated state. Adverse effects, even at minor recreational doses, include increased muscle activity (such as bruxism, restless legs, and jaw clenching), hyperactivity, insomnia, difficulty concentrating and feelings of restlessness.Treatment of MDMA overdose:Emphasis should be on maintaining the airway along with the stabilization of breathing and circulation.Patients may present obtunded due to hyponatremia requiring endotracheal intubation.For the hyperthermic patient, evaporative cooling along with ice packs to the groin and axilla are beneficial.Patients who present in severe toxicity within one hour of ingestion can receive activated charcoal PO or via an NG tube. Antipyretics, such as acetaminophen, should be avoided as they have no role and can worsen an already compromised liver.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 45
Incorrect
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A patient with achalasia
Your Answer:
Correct Answer: Has decreased production of vasoactive intestinal polypeptide (VIP)
Explanation:Oesophageal achalasia is an oesophageal motility disorder involving the smooth muscle layer of the oesophagus and the lower oesophageal sphincter (LES). It is characterized by incomplete LES relaxation, increased LES tone, and lack of peristalsis of the oesophagus (inability of smooth muscle to move food down the oesophagus) in the absence of other explanations like cancer or fibrosis. In achalasia, there is loss of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) releasing inhibitory neurons.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 46
Incorrect
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A 62 year old man arrives at the clinic with a history of cough and intermittent haemoptysis for the last 3 months. He has a 50 pack year smoking history and is currently waiting for bronchoscopy to assess a left lower lobe collapse. The patient also has a marked muscle weakness and wasting of proximal muscles of his shoulders and pelvic girdle. His wife states that lately he has been unable to eat solids. Which of the following statements would be true regarding this scenario?
Your Answer:
Correct Answer: He may have a photosensitive facial rash
Explanation:The patient has presented with signs of small cell lung cancer. The associated proximal muscle weakness is most probably due to dermatomyositis which occurs as a paraneoplastic syndrome associated with lung carcinoma. In most cases, the first symptom is a distinctive skin rash on the face, eyelids, chest, nail cuticle areas, knuckles, knees or elbows. The rash is patchy and usually a bluish-purple colour. Corticosteroids are helpful in the management of the cutaneous changes and muscle weakness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 47
Incorrect
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Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?
Your Answer:
Correct Answer: No blood flow occurs during systole
Explanation:The subendocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 48
Incorrect
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The breakdown of superoxide is catalysed by which enzyme?
Your Answer:
Correct Answer: Superoxide dismutase
Explanation:As superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide-scavenging enzyme superoxide dismutase, or SOD. SOD is an extremely efficient enzyme; it catalyses the neutralization of superoxide nearly as quickly as the two can diffuse together spontaneously in solution.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 49
Incorrect
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Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer:
Correct Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 50
Incorrect
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The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer:
Correct Answer: Pace maker potential
Explanation:Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 51
Incorrect
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Which of the following statements is not true about mitochondrial chromosomes?
Your Answer:
Correct Answer: Mitochondrial chromosomes play no role in the transmission of disease from generation to generation.
Explanation:All the above mentioned statements are true except that mitochondrial DNA is passed from the mother to the child. If the child inherits the defective mitochondrial gene it will manifest some form of the disease. Commonly inherited diseases related to mitochondrial abnormality are Leber hereditary optic neuropathy and myoclonic epilepsy with ragged red fibers (MERRF).
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This question is part of the following fields:
- Genetics
- Medicine
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Question 52
Incorrect
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Which segment of the nephron is impermeable to water?
Your Answer:
Correct Answer: Ascending limb of Henle
Explanation:Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the counter current exchange mechanism employed by the loop.
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This question is part of the following fields:
- Medicine
- Renal
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Question 53
Incorrect
-
The axons of which neurons serve as the only output from the cerebellar cortex?
Your Answer:
Correct Answer: Purkinje
Explanation:The cerebellar cortex consist of 3 layers. The molecular layer, the granule cell layer and the Purkinje cell layer in the middle. The Purkinje cells project into the deep cerebellar nuclei. They are the only output cells of the cerebellar cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 54
Incorrect
-
Which of the following occurs during a Valsalva manoeuvre?
Your Answer:
Correct Answer: An initial rise in blood pressure
Explanation:The Valsalva maneuver involves forced expiration against a closed glottis. It has several phases, each affecting the cardiovascular system differently:
- Phase I: During the initial forced expiration against the closed glottis, there is a transient rise in intrathoracic pressure, which compresses the thoracic aorta and causes a brief increase in blood pressure.
- Phase II: Continued straining leads to decreased venous return to the heart, reducing cardiac output and causing a drop in blood pressure. This phase is characterized by a compensatory increase in heart rate.
- Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
- Phase IV: Blood pressure then rises rapidly as venous return to the heart is restored, leading to increased cardiac output. This is often followed by a reflex bradycardia (slow heart rate).
Given these phases, the most accurate statement about what occurs during the Valsalva maneuver is the initial rise in blood pressure (Phase I).
Other options explained:
- Forced inspiration against a closed glottis: Incorrect. The Valsalva maneuver involves forced expiration, not inspiration, against a closed glottis.
- Low intrathoracic pressures throughout: Incorrect. The Valsalva maneuver involves high intrathoracic pressures due to forced expiration.
- Disruption of autonomic function: Incorrect. The Valsalva maneuver affects autonomic function but does not disrupt it. Instead, it triggers autonomic responses to changes in blood pressure and heart rate.
- No change: Incorrect. The Valsalva maneuver causes significant changes in blood pressure and heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 55
Incorrect
-
In a knockout mouse model the process used to combine the new DNA sequence and the stem cells is known as:
Your Answer:
Correct Answer: Insertion
Explanation:Chimerisation is also known as the formation of recombinant DNA. When a foreign DNA sequence is inserted into a plasmid or other DNA sequence, this process is known as insertion.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 56
Incorrect
-
The interventricular septum is supplied anteriorly by the?
Your Answer:
Correct Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 57
Incorrect
-
Which statement is incorrect regarding nociceptor C fibers…
Your Answer:
Correct Answer: They are thinly myelinated
Explanation:Group C nerve fibers are unmyelinated and have a small diameter, which means they conduct impulses at a low velocity. They carry sensory information and nociception.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 58
Incorrect
-
A 70-year-old man presents with nocturia, hesitancy and terminal dribbling of urine. Prostate examination reveals a moderately enlarged prostate with no irregular features and a well-defined median sulcus. Blood investigations show a PSA level of 1.3 ng/mL. Among the options provided below what is the most appropriate management for this patient?
Your Answer:
Correct Answer: Alpha-1 antagonist
Explanation:Benign Prostatic Enlargement or Hyperplasia (BPE/BPH) is the most probable diagnosis of the patient in question. It is a histological diagnosis characterized by proliferation of the cellular elements of the prostate. The initial treatment modality of choice is selective alpha 1 antagonists (such as Prazosin, Alfuzosin and Indoramin, and long acting agents like, Terazosin, Doxazosin, etc.) as they provide immediate relief from the bothersome lower urinary tract symptoms (LUTS).Other treatment modalities include:• Non-selective alpha blockers: no longer used due to severe adverse effects and the availability of selective alpha 1 blockers.• 5 alpha reductase inhibitors: Finasteride and Dutasteride, they target the underlying disease process and reduce the overall prostate volume. Thus, reduce the urinary retention and the lower urinary tract symptoms. (They do not provide immediate relief from LUTS and thus are not preferred as first line drugs over alpha 1 antagonists)• PDE-5 Inhibitors: The long-acting tadalafil has proven to be useful.• Surgical Treatment modalities: TURP, Prostatectomy, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 59
Incorrect
-
The oesophagus is lined by
Your Answer:
Correct Answer: Stratified squamous epithelium
Explanation:The wall of the oesophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epithelium of around three layers of squamous cells, which contrasts to the single layer of columnar cells of the stomach. The transition between these two types of epithelium is visible as a zig-zag line. Most of the muscle is smooth muscle although striated muscle predominates in its upper two thirds.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 60
Incorrect
-
Which of the atrial pressure changes represents the a-wave of the JVP
Your Answer:
Correct Answer: Atrial systole
Explanation:The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 61
Incorrect
-
Which statement about antithrombin III is true?
Your Answer:
Correct Answer: It inhibits particularly factor II and X
Explanation:Antithrombin inactivates its physiological target enzymes, Thrombin (Factor II), Factor Xa and Factor IXa. ATIII binds to thrombin and then forms the thrombin-anti thrombin complex or TAT complex. This is a major natural pathway of anticoagulation. This binding of thrombin to AT is greatly enhanced in the presence of heparin.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 62
Incorrect
-
Of the daily production of CSF, the vast majority is produced in the:
Your Answer:
Correct Answer: Choroid plexus
Explanation:About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 63
Incorrect
-
Which of the following is true of the Natriuretic hormones?
Your Answer:
Correct Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 64
Incorrect
-
The parasympathetic function of the facial nerve is:
Your Answer:
Correct Answer: Secretion of tears from lacrimal glands, secretion of saliva from the sublingual and submandibular salivary glands.
Explanation:Facial nerve (Cranial Nerve VII) has both sensory and motor components so it is a mixed nerve. It carries axons of:General somatic afferent – to skin and the posterior earGeneral visceral efferent – which innervate sublingual, submandibular and lacrimal glands and the mucosa of the nasal cavity.General visceral afferent – provide sensation to soft palate and parts of the nasal cavity.Special visceral efferent – innervate muscles of facial expression and stapedius, the posterior belly of the digastric and the stylohyoid musclesSpecial visceral afferent – provide taste to the anterior two-thirds of the tongue via chorda tympani.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 65
Incorrect
-
Inactive cellular marrow is called
Your Answer:
Correct Answer: Yellow marrow
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 66
Incorrect
-
Which is the primary lymphoid organ?
Your Answer:
Correct Answer: Thymus
Explanation:Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 67
Incorrect
-
Where does the SA node develop?
Your Answer:
Correct Answer: From structures on the right side of the embryo.
Explanation:The SA node develops from the right side of the embryo and the AV node from the left. This is the reason why in adults the right vagus supplies the SA node and the left vagus supplies the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 68
Incorrect
-
Which of the following best describes the cardiac muscle?
Your Answer:
Correct Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 69
Incorrect
-
Which one of the following cells originates from a monocyte and resembles a macrophage?
Your Answer:
Correct Answer: Microglia
Explanation:Microglia act as the macrophages of the central nervous system, and they contribute to innate and adaptive immune responses. Studies have shown that microglial cells recognize monocyte antigens, and there are similarities between them that demonstrate that they originate from these monocytes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 70
Incorrect
-
What is the function of migrating motor complex
Your Answer:
Correct Answer: Clears the gut of luminal contents in preparation of the next meal
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon. The MMC occurs every 90–120 minutes during the interdigestive phase (between meals), and is responsible for the rumbling experienced when hungry. It also serves to transport bacteria from the small intestine to the large intestine, and to inhibit the migration of colonic bacteria into the terminal ileum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 71
Incorrect
-
Ventricular depolarization plus ventricular repolarization is shown by the _____ interval
Your Answer:
Correct Answer: QT
Explanation:The QT interval represents ventricular depolarization as well as ventricular repolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 72
Incorrect
-
A sarcomere is the area between:
Your Answer:
Correct Answer: Two adjacent z lines
Explanation:The area that lies between the two adjacent Z lines is known as a sarcomere and is the contractile unit of the muscle. The line passing in the middle of the myosin filaments is the M line. It also passes through the middle of the sarcomere.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 73
Incorrect
-
The function of Troponin T in cardiac muscle is?
Your Answer:
Correct Answer: Allows attachment of troponin components to tropomyosin
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin, and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 74
Incorrect
-
A 55 year old cardiac patient is comfortable at rest but heavy housework results in fatigue, palpitations or dyspnoea. What New York Heart Association class best describes the severity of their disease?
Your Answer:
Correct Answer: NYHA Class II
Explanation:New York Heart Association functional classification:
Class I: no limitation is experienced in any activities; there are no symptoms from ordinary activities.
Class II: slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
Class III: marked limitation of any activity; the patient is comfortable only at rest.
Class IV: any physical activity brings on discomfort and symptoms occur at rest.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 75
Incorrect
-
Lipid- lowering drugs like Lovastatin reduce cholesterol synthesis by inhibiting which enzyme?
Your Answer:
Correct Answer: HMG-CoA reductase
Explanation:Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications. Statins have been found to reduce cardiovascular disease (CVD) and mortality in those who are at high risk.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 76
Incorrect
-
A 74 year old man presents with 12 kg weight loss and persistent back pain that is unrelated to activity for the past several months. Laboratory findings show :WCC: 6.7 x 109/l (5.4 neutrophils, 1.2 lymphocytes and 0.2 monocytes)Haemoglobin: 11.2 g/dlhaematocrit: 33.3%MCV: 88 flPlatelet count: 89 x 109/l.The biochemistry shows:sodium 144 mmol/lpotassium 4.5 mmol/lchloride 100 mmol/lbicarbonate 26 mmol/lurea 14 mmol/lcreatinine 90 μmol/la glucose of 5.4 mmol/l.A CT scan of the spine reveals scattered 0.4 to 1.2 cm bright lesions in the vertebral bodies.Which of the following additional laboratory test findings is he most likely to have?
Your Answer:
Correct Answer: Serum prostate specific antigen of 35 microgram/l
Explanation:Old age, persistent backache, weight loss, and osteosclerotic lesions make prostatic adenocarcinoma the most likely diagnosis. The sequelae include severe pain, pathological fractures, hypercalcemia and cord compression. Prostatic adenocarcinoma is detected by elevated levels of prostate specific antigen. Positive serology for borrelia burgdorferi would hint at Lyme disease which does not cause osteosclerotic bone lesions, neither would Neisseria gonorrhoeae have such a presentation.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 77
Incorrect
-
von Willebrand factor stabilises which clotting factor?
Your Answer:
Correct Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 78
Incorrect
-
Conjugation of proteins to which polypeptide marks them for degradation?
Your Answer:
Correct Answer: Ubiquitin
Explanation:Ubiquitin is a small regulatory protein that affects proteins in many ways: it can mark them for degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions. Ubiquitination involves three main steps: activation, conjugation, and ligation,
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 79
Incorrect
-
Which vaso metabolite decreases coronary blood flow?
Your Answer:
Correct Answer: Endothelin
Explanation:Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 80
Incorrect
-
What catalyses the conversion of adenosine to inosine?
Your Answer:
Correct Answer: Adenosine deaminase
Explanation:Adenosine deaminase (ADA) is an enzyme involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues. ADA irreversibly deaminates adenosine, converting it to the related nucleoside inosine by the substitution of the amino group for a keto group.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 81
Incorrect
-
The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?
Your Answer:
Correct Answer: Ca
Explanation:Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 82
Incorrect
-
Which of the following values of bone mineral density measured by DEXA would signify osteopenia?
Your Answer:
Correct Answer: T score of -2.2
Explanation:DEXA T Scores:Normal T-score ≥ −1.0Osteopenia −2.5 < T-score < −1.0Osteoporosis T-score ≤ −2.5Severe osteoporosis T-score ≤ −2.5 with fragility fracture
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 83
Incorrect
-
ANP and BNP in the circulation act on the kidney to?
Your Answer:
Correct Answer: Increase sodium excretion
Explanation:The physiologic actions of BNP are similar to those of ANP and include decrease in systemic vascular resistance and central venous pressure as well as an increase in natriuresis (sodium excretion). The net effect of these peptides is a decrease in blood pressure due to the decrease in systemic vascular resistance and, thus, afterload.
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This question is part of the following fields:
- Medicine
- Renal
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Question 84
Incorrect
-
A 70-year-old woman is having trouble in speaking following a stroke. Her limbs are paralyzed, both left upper and lower limbs. Which anatomical site is most likely affected?
Your Answer:
Correct Answer: Internal capsule
Explanation:– The given scenario is typical of lesion in internal capsule. – Memory impairment is caused by a hippocampal lesion, – Impairment of arousal, facial paresis, visual field defect, facial paresis, hemiataxia, and hemispacial neglect are just some of the conditions caused by thalamic lesion. – Brainstem stroke on the other hand causes breathing abnormality, altered consciousness, and blood pressure disorder.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 85
Incorrect
-
Where do the spinothalamic axons decussate?
Your Answer:
Correct Answer: Spinal cord
Explanation:The second order neurons from the spinothalamic tract cross obliquely to the opposite side in the anterior grey and white commissure within one segment of the spinal cord.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 86
Incorrect
-
The TSH receptor produces its effects in the thyrocyte via:
Your Answer:
Correct Answer: G-protein coupled activation of adenylyl cyclise and phospholipase c
Explanation:The thyrotropin receptor, also known as TSH receptor, responds to the thyroid stimulating hormone or thyrotropin to stimulate production of T3 and T4. It is a G protein-coupled receptor which leads to stimulation of phospholipase C and adenylyl cyclase, mediated by Gq/11 and Gs.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 87
Incorrect
-
A 28 year old man was rushed to the hospital after experiencing sudden onset chest pain while playing football. He has never felt such pain in the past. However, one of his uncles had a similar sudden discomfort at a young age and he passed away following a heart problem. The following vitals are recorded on examination:BP: 101/74 mmHgRR: 22 breaths/minPR: 87 beats/min Physical examination reveals abnormally long fingers and on asking the man to hold the opposite wrist, the thumb and little finger overlap each other. He is not taking any medication regularly and past medical/surgical history is not significant. He admits to smoking half pack of cigarettes/day for the last 10 years but denies abusing any illicit drugs. Which of the following explanation most likely explains the disease process in this man?
Your Answer:
Correct Answer: A defect of the glycoprotein structure which usually wraps around elastin
Explanation:Aortic dissection is defined as separation of the layers within the aortic wall. Tears in the intimal layer result in the propagation of dissection (proximally or distally) secondary to blood entering the intima-media space. This can be caused as a result of both congenital or acquired factors like chronic uncontrolled hypertension. This patient shows no sign of hypertension but his physical examination hints towards Marfan Syndrome. Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder affecting the microfibrils and elastin in connective tissue throughout the body. MFS is associated with pathological manifestations in the cardiovascular system (e.g., mitral valve prolapse, aortic aneurysm, and dissection), the musculoskeletal system (e.g., tall stature with disproportionately long extremities, joint hypermobility), and the eyes (e.g., subluxation of the lens of the eye). Decreased collagen production occurs in ageing, hydroxylation defects are present in vitamin C deficiency, copper deficiency affecting lysyl oxidase enzyme occurs in Menke’s disease.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 88
Incorrect
-
An obstruction in a pulmonary artery causes impaired perfusion to an area in the lung. The gas values in the unperfused alveoli at sea level will be:
Your Answer:
Correct Answer: PO2 = 149 C02 =0
Explanation:Partial pressure of oxygen at sea level is approximately 160 mmHg. Partial pressure of oxygen in alveoli is around 150 mmHg and in an arteriole is around 80-100 mmHg. Partial pressure of carbon dioxide is around 35 mmHg in alveolar air and around 40 mmHg in the arteriole.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 89
Incorrect
-
What is the average life span of red blood cells?
Your Answer:
Correct Answer: 4 months
Explanation:Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days (4 months) in the body before their components are recycled by macrophages.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 90
Incorrect
-
The areas of extensive series of sarcoplasmic folds known as intercalated discs always occur at what portion of the muscle fiber?
Your Answer:
Correct Answer: Z lines
Explanation:The muscle fibers of the heart branch and interdigitate, but one complete unit is surrounded by a cell membrane. The place where one muscle fiber abuts the other, the cell membrane of both the fibers run parallel to each other through a series of extensive folds. These areas always occur on the Z lines and are known as intercalated discs.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 91
Incorrect
-
Where would one normally find venous valves?
Your Answer:
Correct Answer: Saphenous vein
Explanation:The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 92
Incorrect
-
A 45 year old man, known case of hypothyroidism, presents with a 3 month history of pain and stiffness in the joints of his hands and feet. He also complains of dyspnoea occurring for the past 6 weeks. On examination there is a right pleural effusion and swollen hand joints. The clinician makes a diagnosis of rheumatoid arthritis. Which of the following is most characteristic of a rheumatoid pleural effusion?
Your Answer:
Correct Answer: It has a low glucose level
Explanation:The typical “rheumatoid effusion” is a sterile exudative fluid with low pH (<7.3), low glucose (700 IU). It should initially be treated with NSAIDs. Decortication should be reserved in patients with thickened pleura who have symptomatic dyspnoea.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 93
Incorrect
-
Where is the lower border of the liver usually found?
Your Answer:
Correct Answer: 10th rib anterior axillary line on right
Explanation:Assessment of liver margins is important clinically to determine the size of the liver and is done via percussion during the physical examination. The liver typically extends from the fifth intercostal space or 6th rib to the right costal margin in the midclavicular line and the 10th rib on anterior axillary line.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
-
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Question 94
Incorrect
-
Question 95
Incorrect
-
Vasodilatation in skeletal muscle can be caused by:
Your Answer:
Correct Answer: Sympathetic cholinergic nerves
Explanation:In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 96
Incorrect
-
Dynein proteins transmit polypeptides/proteins in which direction?
Your Answer:
Correct Answer: From axons terminals to cell body (retrograde)
Explanation:The majority of axonal proteins are synthesised in the cell body and transported along the axons. Microtubules run along the length of the axon and provide tracks for transportation. Kinesin and Dynein are motor proteins that transport proteins and other organelles. Kinesin moves forward or anterograde transport from cell body to axon, whereas Dynein moves retrograde from axon to cell body.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 97
Incorrect
-
Which one of the following is true about bone marrow?
Your Answer:
Correct Answer: At birth the bone marrow is entirely red marrow and is converted to yellow marrow with age
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells. Red blood cells, platelets, and most white blood cells arise in red marrow. Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 98
Incorrect
-
Which of the following may be a feature of primary hyperaldosteronism?
Your Answer:
Correct Answer: Muscular weakness
Explanation:Primary hyperaldosteronism or Conn’s syndrome is characterised by hypertension which may cause poor vision or headaches. Occasionally there may be muscular weakness, muscle spasms, tingling sensations, or excessive urination. Complications include cardiovascular disease such as stroke, myocardial infarction, kidney failure, and abnormal heart rhythms.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 99
Incorrect
-
Concerning surface anatomy, where is the mitral valve found?
Your Answer:
Correct Answer: Situated in the 4th intercostal space to the left of the sternum
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 100
Incorrect
-
What is the mechanism of action of carbimazole?
Your Answer:
Correct Answer: Inhibition of the iodination of tyrosine
Explanation:Carbimazole is used to treat hyperthyroidism. Carbimazole is a pro-drug as after absorption it is converted to the active form, methimazole. Methimazole prevents thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4 (thyroxine).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 101
Incorrect
-
A 20 year old male student presents to the clinic with swelling of his face, hands and feet along with diffuse abdominal pain. He has a history of similar recurrent episodes since he was 10 years old, with each episode lasting 2-3 days. Examination reveals swelling on face, hands, feet but no sign of urticaria. Family history is significant for similar episodes in the mother who experienced these since childhood, and a brother who passed away following respiratory distress at age of 8 during one such episode. Which of the following tests would be the most helpful in reaching the diagnosis?
Your Answer:
Correct Answer: C1 esterase inhibitor
Explanation:Hereditary C1 inhibitor deficiency leads to recurrent angioedema without urticaria or pruritus. Physical triggers include dental work, surgery or intubation. Medical triggers include angiotensin-converting enzyme (ACE) inhibitor, tamoxifen, oestrogen-containing medications (e.g., hormone replacement therapy and oral contraceptives). It is diagnosed on the basis of low levels of C1 esterase inhibitor or elevated levels of dysfunctional C1 esterase inhibitor. C4 levels are low between attacks. IgE levels, eosinophils, skin prick tests and RASTs are helpful in other allergic conditions and asthma but not of use in this case.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 102
Incorrect
-
A 42 year old female with a history of SLE presents with an exacerbation of wrist pain. Which of the following markers would be the most suitable for monitoring disease activity?
Your Answer:
Correct Answer: Anti-dsDNA titres
Explanation:A high level of anti-dsDNA in the blood is strongly associated with lupus and is often significantly increased during or just prior to a flare-up. When the anti-dsDNA is positive and the person tested has other clinical signs and symptoms associated with lupus, it means that the person tested likely has lupus. This is especially true if an anti-Sm test is also positive.In the evaluation of someone with lupus nephritis, a high level (titre) of anti-dsDNA is generally associated with ongoing inflammation and damage to the kidneys.A very low level of anti-dsDNA is considered negative but does not exclude a diagnosis of lupus. Only about 65-85% of those with lupus will have anti-dsDNA.Low to moderate levels of the autoantibody may be seen with other autoimmune disorders, such as Sjögren syndrome and mixed connective tissue disease (MCTD).
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 103
Incorrect
-
Choose the correct statement regarding the protein C/S system?
Your Answer:
Correct Answer: The protein C/S complex inactivates factor Va and VIIIa
Explanation:The best characterized function of Protein S is its role in the anti coagulation pathway, where it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 104
Incorrect
-
Acetylcholine from enteric nerve endings stimulates this pair:
Your Answer:
Correct Answer: Parietal cells and chief cells
Explanation:In the body of the stomach, the vagal postganglionic muscarinic nerves release acetylcholine(ACh) which stimulates parietal cell H+ secretion. Gastric chief cells are primarily activated by ACh. However the decrease in pH caused by activation of parietal cells further activates gastric chief cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 105
Incorrect
-
Using the Cockcroft-Gault formula, what will the estimated creatinine clearance be of a 55 year old male who weighs 75kg and has a serum creatinine of 150mg/dL?
Your Answer:
Correct Answer: 0.59ml/min
Explanation:A commonly used surrogate marker for estimate of creatinine clearance is the Cockcroft-Gault (CG) formula, which in turn estimates GFR in ml/min:CCr = [(140-age) x Mass(kg)]/[72 x serum creatinine (mg/dL)](multiply by 0.85 for women)Therefore CCr = (85 x 75)/(72 x 150) = 0.59
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This question is part of the following fields:
- Medicine
- Renal
-
-
Question 106
Incorrect
-
Vagotomy leads to the following:
Your Answer:
Correct Answer: Irregular and chaotic peristalsis
Explanation:The Vagus nerve is primarily responsible for autonomic regulation involved in heart, lung and gastrointestinal function. The gastric branches supply the stomach. The right branch joins the celiac plexus and supplies the intestines. Vagotomy involves cutting of the vagus nerve or its branches which is a now-obsolete therapy that was performed for peptic ulcer disease. Vagotomy causes a decrease in peristalsis and a change in the emptying patterns of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 107
Incorrect
-
Where is the carotid sinus located?
Your Answer:
Correct Answer: After the bifurcation of the carotid artery, on the internal carotid
Explanation:The carotid sinus is a small dilation in the internal carotid artery just above its bifurcation into the external and internal carotid branch. Baroreceptors are present at this dilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 108
Incorrect
-
During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer:
Correct Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 109
Incorrect
-
Mutation in RB can lead to the formation of which cancer?
Your Answer:
Correct Answer: Retinoblastoma
Explanation:Patients with a history of autosomal dominant familial retinoblastoma have at least one mutated copy of the RB gene. This predisposes the patient to develop retinoblastoma in one or both the eyes. Patients with a family history should be screened properly so that it can be detected and treated as early as possible.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 110
Incorrect
-
Which of the following is responsible for converting inactive cortisone to active cortisol in the adrenal gland?
Your Answer:
Correct Answer: 11βHSD type 1
Explanation:11β-Hydroxysteroid dehydrogenase, also known as HSD-11β or 11β-HSD, is a group of enzymes which catalyse the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 111
Incorrect
-
When is the blood pressure at its lowest during pregnancy?
Your Answer:
Correct Answer: Second trimester
Explanation:It is lowest during the second trimester.
Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 112
Incorrect
-
Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?
Your Answer:
Correct Answer: Vasodilation via production of metabolites
Explanation:The coronary arterioles contain α-adrenergic receptors, which cause vasoconstriction, and β-adrenergic receptors, which cause vasodilation. Activity in the noradrenergic nerves to the heart and injections of norepinephrine cause coronary vasodilation. However, norepinephrine also increases the heart rate and the force of cardiac contraction, and the vasodilation is due to production of vasodilator metabolites in the myocardium secondary to the increase in its activity. As exercise has the same effect as sympathetic stimulation, it will result in vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 113
Incorrect
-
A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg at night for Addison’s disease. The endocrinology consultant would like her to take prednisolone instead. What dose of prednisolone should be started?
Your Answer:
Correct Answer: 7 mg
Explanation:1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 114
Incorrect
-
In the malaria life cycle , parasites which remain dormant in the liver are known as :
Your Answer:
Correct Answer: Hypnozoites
Explanation:The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 115
Incorrect
-
Which of the following is not a feature of Liddle’s syndrome?
Your Answer:
Correct Answer: Autosomal recessive inheritance
Explanation:Liddle’s syndrome is a rare autosomal dominant condition characterized by early, and frequently severe, high blood pressure associated with low plasma renin activity, metabolic alkalosis, low blood potassium, and normal to low levels of aldosterone. Liddle syndrome involves abnormal kidney function, with excess reabsorption of sodium and loss of potassium from the renal tubule, and is treated with a combination of low sodium diet and potassium-sparing diuretic drugs (e.g., amiloride).
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 116
Incorrect
-
Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer:
Correct Answer: Troponin c
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 117
Incorrect
-
Which of the following is not secreted by cells in the antrum of the stomach?
Your Answer:
Correct Answer: Hydrochloric acid
Explanation:Cells in the body of the stomach secrete mucus, HCl and pepsinogen. Cells in the antrum secrete pepsinogen, gastrin and mucus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 118
Incorrect
-
Which is the most common site for primary cardiac tumours to occur in adults?
Your Answer:
Correct Answer: Left atrium
Explanation:Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 119
Incorrect
-
Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?
Your Answer:
Correct Answer: Dihydropyridine receptors
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.
Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.
Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 120
Incorrect
-
Vitamin K deficiency can be found in which of the following condition?
Your Answer:
Correct Answer: Cholestatic jaundice
Explanation:Vitamin K1-deficiency may occur by disturbed intestinal uptake (such as would occur in a bile duct obstruction), by therapeutic or accidental intake of a vitamin K1-antagonist such as warfarin, or, very rarely, by nutritional vitamin K1 deficiency.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 121
Incorrect
-
What is pendrin?
Your Answer:
Correct Answer: Cl-/i- antiporter
Explanation:Pendrin is an anion exchange transporter; it is a sodium-independent chloride-iodine exchanger which also accepts formate and bicarbonate. It is present in many different types of cells in the body, particularly the inner ear, thyroid, and kidney. Mutations in pendrin are associated with Pendred syndrome, which causes syndromic deafness and thyroid disease.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 122
Incorrect
-
Which immunological cells are predominant in the lymph node (almost 98 % residence)?
Your Answer:
Correct Answer: Lymphocytes
Explanation:Lymph nodes are a lymphoid organ mostly consisting of lymphocytes: B cells in the cortex from where they mature and proliferate and T cells in the paracortex. The medulla is also composed of lymphocytes and macrophages.
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This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 123
Incorrect
-
Where in the course of the gastrointestinal tract does the first significant digestion of fat begin in a normal human being?
Your Answer:
Correct Answer: Duodenum
Explanation:The enzyme lipase which is responsible for digestion of fat is secreted by the exocrine pancreas in the 2nd part of the duodenum at the point where the pancreatic duct opens. It opens together with the common bile duct which contains bile that emulsify fat aiding in digestion. The oesophagus, stomach and mouth do not contain enzymes related to fat digestion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 124
Incorrect
-
Which enzyme is responsible for the removal of acetylcholine from the synapse?
Your Answer:
Correct Answer: Acetylcholinesterase
Explanation:Acetylcholinesterase is the enzyme that is responsible for breaking down acetylcholine into choline and acetate. Both of these molecules are transported back to the presynaptic neuron to be synthesized again. This enzyme is attached to the collagen fibers of the basement membrane in the synaptic cleft.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 125
Incorrect
-
The basic unit of contraction in myocytes is:
Your Answer:
Correct Answer: Sarcomere
Explanation:Sarcomere is the organelle where calcium is stored to be released during contraction of the muscle. It is the basic unit of contraction in striated muscle fibers. As myocytes are also striated muscles, sarcomeres also forms the basic unit of contraction. The impulses travel along the membrane and via its interaction with the dihydropyridine receptors it releases the stored calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 126
Incorrect
-
On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your Answer:
Correct Answer: Α2 receptor
Explanation:Adregenic receptors are A1, A2, B1, B2, B3. Out of these, the function of the A2 receptor is inhibition of transmitter release including nor adrenalin and acetylcholine of the autonomic nervous system.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 127
Incorrect
-
The complete oxidation of 1 molecule of glucose to CO2 and H20 produces a total of __ATP.
Your Answer:
Correct Answer: 38
Explanation:Textbooks often state that 38 ATP molecules can be made per oxidised glucose molecule during cellular respiration (2 from glycolysis, 2 from the Krebs cycle, and about 34 from the electron transport system). However, this maximum yield is never quite reached because of losses due to leaky membranes as well as the cost of moving pyruvate and ADP into the mitochondrial matrix, and current estimates range around 29 to 30 ATP per glucose.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 128
Incorrect
-
Protein digestion starts in the stomach by which enzyme?
Your Answer:
Correct Answer: Pepsin
Explanation:Pepsinogen is the inactive form of pepsin which is secreted by gastric chief cells and is converted to pepsin, in the presence of gastric HCL. Pepsin is a peptidase that breaks down proteins into smaller peptides.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 129
Incorrect
-
The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your Answer:
Correct Answer: CN IX
Explanation:Parasympathetic presynaptic nerve fibers from the glossopharyngeal nerve (CN IX) synapse in the otic ganglion and the postsynaptic parasympathetic nerve fibers pass to the parotid gland via the auriculotemporal nerve.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 130
Incorrect
-
Which of the following is an example of a ketone body?
Your Answer:
Correct Answer: Acetoacetate
Explanation:Ketone bodies are three water-soluble molecules (acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone) that are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus.
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This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 131
Incorrect
-
Which of the following cells secrete glucagon?
Your Answer:
Correct Answer: A cells
Explanation:Glucagon counteracts hypoglycaemia and opposes insulin by promoting gluconeogenesis and glycogenolysis. It also decreases fatty acid synthesis in the liver and adipose tissue, and promotes lipolysis. It is secreted by the pancreatic islet α-cells. Its production is regulated by the insulin produced in β-cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 132
Incorrect
-
Somatostatin is responsible for?
Your Answer:
Correct Answer: Decreased gastrin release
Explanation:Somatostatin is an inhibitory hormone secreted from the D cells of the Pancreatic Islets. It causes the inhibition of gastrin (decreasing stomach acid production), CCK (decreasing gallbladder motility), gastrin inhibitory peptide and secretin. Gastrin production is also inhibited by secretin, GIP, VIP, glucagon and calcitonin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 133
Incorrect
-
Question 134
Incorrect
-
The principle by which the energy of contraction is proportional to the initial length of cardiac muscle fiber is known as:
Your Answer:
Correct Answer: Starling’s law
Explanation:The Frank starling relationship describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increase venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and increased development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relation is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 135
Incorrect
-
Although variable, branches of which artery most often supply the SA and AV nodes?
Your Answer:
Correct Answer: Right coronary artery
Explanation:The RCA (right coronary artery) supplies the SA and the AV nodes along with the postero-basal wall of the left ventricle, posterior one third of the inferior vena cava, right ventricle and the posteromedial papillary muscle in the left ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 136
Incorrect
-
When 2 nucleotide chains of DNA bind together, thymine is bound to:
Your Answer:
Correct Answer: Adenine
Explanation:As a general rule in the structure of DNA, thymine always binds to adenine with two hydrogen bonds, cytosine always binds to guanine with three hydrogen bonds and vice versa. However In the structure of RNA the only difference is that adenine binds to uracil instead of thymine. But thymine will always bind to adenine.
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This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 137
Incorrect
-
The coronary arteries supply which part of the heart’s subendocardial region exclusively in diastole?
Your Answer:
Correct Answer: Left ventricle
Explanation:It is only during diastole that the blood flows to the subendocardial portion of the left ventricle, as the heart muscle relaxes and the coronary arteries regain their patency.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 138
Incorrect
-
In a study, 50 out of 100 smokers developed lung cancers and 50 out of 200 non-smokers developed lung cancers. Which of the following is accurate?
Your Answer:
Correct Answer: Relative risk=2
Explanation:Relative risk = (Incidence in exposed group)/incidence in unexposed group). So in this case RR = (50/100)/(50/200) = 2.
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This question is part of the following fields:
- Medicine
- Research Skills
-
-
Question 139
Incorrect
-
In the olfactory pathway: Mitral cells project to five regions of the olfactory cortex. Which one of the following is not one of the five regions?
Your Answer:
Correct Answer: Posterior olfactory nucleus
Explanation:The olfactory system contains peripheral and central divisions which are connected by transduction structures. Peripheral division consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium. Olfactory neurons are receptor cells in the epithelium that detect odour molecules dissolved in the mucus and transmit information about the odour to the brain in a process called sensory transduction. Olfactory nerves and fibers transmit information about odours from the peripheral olfactory system to the central olfactory system of the brain. The main olfactory bulb transmits pulses to both mitral and tufted cells, which help determine odour concentration. These cells also note differences between highly similar odours and use that data to aid in later recognition. The cells are different with the mitral having low firing-rates and being easily inhibited by neighbouring cells, while tufted have high rates of firing and are more difficult to inhibit. The uncus houses the olfactory cortex which includes the piriform cortex, amygdala, olfactory tubercle, and para-hippocampal gyrus. Entorhinal cortex is an area of middle temporal lobe that has connection with the para-hippocampal gyrus.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 140
Incorrect
-
During exercise, a man consumes 2L O2/min, his arterial 02 content is 190 ml/l and the 02 content of his mixed venous blood is 130ml/l. His cardiac output is approximately:
Your Answer:
Correct Answer: 33l/min
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Therefore CO = 2/(0.190-0.130) = 33l/minNote that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 141
Incorrect
-
Which of the following components regulate cardiac output?
Your Answer:
Correct Answer: All of the above
Explanation:Cardiac output is regulated by the autonomic nervous system with sympathetic nerves having a positive chronotropic and inotropic effect and parasympathetic nerves having the opposite effect. An increase in preload will increase cardiac output likewise an afterload increase will also increase cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 142
Incorrect
-
Which one of the following diseases is correctly matched with the animal reservoir:
Your Answer:
Correct Answer: Leptospirosis = Rats
Explanation:Creutzfeldt–Jakob disease = consuming beef or beef products.Brucellosis = ingestion of unpasteurized milk or undercooked meat from infected animals.Leptospirosis is transmitted by both wild and domestic animals. The most common animals that spread the disease are rodents.Lyme disease is transmitted to humans by the bite of infected ticks of the Ixodes genus.Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania and spread by the bite of certain types of sandflies.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 143
Incorrect
-
The following occurs as a result of 2,3 Bisphosphoglycerate binding to deoxyhaemoglobin
Your Answer:
Correct Answer: A reduction in deoxyhaemoglobin's affinity for oxygen
Explanation:2,3-BPG acts as a heteroallosteric effector of haemoglobin, lowering haemoglobin’s affinity for oxygen by binding preferentially to deoxyhaemoglobin. An increased concentration of BPG in red blood cells favours formation of the T, low-affinity state of haemoglobin and so the oxygen-binding curve will shift to the right.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 144
Incorrect
-
A 82-year-old woman admitted following a fractured neck of femur has been discharged. On review, she is making good progress but consideration is given to secondary prevention of further fractures. What is the most appropriate step in the prevention of further fractures?
Your Answer:
Correct Answer: Start oral bisphosphonate
Explanation:In such a clinical scenario, NICE guidelines support initiating treatment with bisphosphonates without waiting for a DEXA scan.Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.Management:Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D repleteAlendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 145
Incorrect
-
Pancreatic juice is usually?
Your Answer:
Correct Answer: Alkaline
Explanation:Pancreatic juice is alkaline in nature and has a high amount of bicarbonate ions. About 1500 ml is secreted every day. It also contains a large quantity of enzymes in the inactive form.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 146
Incorrect
-
Concerning the sleep-wake cycle, Melatonin is secreted by which structure in the brain following which environmental conditions?
Your Answer:
Correct Answer: Pineal gland, darkness
Explanation:Melatonin is secreted by the pineal gland located in the midline attached to the posterior roof of the third ventricle in the brain. Melatonin affects circadian rhythm in the body or the sleep wake cycle. The precursor to melatonin is serotonin and the rate limiting enzyme that converts serotonin to melatonin is low during the day time and reaches its peak during the night.
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This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 147
Incorrect
-
A 72-year-old with varicose veins complains of swollen, red, itchy legs. Which is the most likely diagnosis?
Your Answer:
Correct Answer: Varicose eczema
Explanation:Varicose eczema is a common problem, particularly in elderly patients due to stasis or blood pooling from insufficient venous return; the alternative name of varicose eczema comes from a common cause of this being varicose veins. It is often mistaken for cellulitis, but cellulitis is rarely bilateral and is painful rather than itchy.
-
This question is part of the following fields:
- Dermatology
- Medicine
-
-
Question 148
Incorrect
-
Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly during:
Your Answer:
Correct Answer: Diastole
Explanation:The sub endocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure from contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the sub endocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 149
Incorrect
-
The lower oesophageal sphincter is under neural control. Which of the following causes contraction of the intrinsic sphincter?
Your Answer:
Correct Answer: Acetylcholine
Explanation:The lower oesophageal sphincter (LOS) is a specific region of the oesophageal circular smooth muscle. It allows the passage of a food bolus to the stomach and prevents the reflux of gastric contents into the oesophagus. The tone of the LOS is myogenic in origin and depends on smooth muscle properties that lead to the opening of Ca2+ channels but can also be modulated by enteric motor neurons, the parasympathetic and sympathetic extrinsic nervous system and several neurohumoral substances. Nitric oxide causes LOS relaxation. Acetylcholine and tachykinins are involved in the LOS contraction.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 150
Incorrect
-
Water hammer pulse is found in:
Your Answer:
Correct Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 151
Incorrect
-
A 64 year old female presents with sudden onset pain, swelling and stiffness in her right knee. Her medical history is significant for osteoarthritis affecting her hand joints and diet controlled diabetes mellitus. On examination, the right knee is swollen, erythematous and tender. Which of the following tests would be most useful in the diagnosis of this case?
Your Answer:
Correct Answer: Aspiration and examination of the synovial fluid
Explanation:Arthrocentesis should usually be done when there is a suspicion of pseudogout or septic arthritis as in this case which leads to an early diagnosis and prompt treatment. Polarized microscopy demonstrates weakly positively birefringent rhomboid crystals which are blue when parallel to light and yellow when perpendicular to light. Elevated serum uric acid levels that cause gout are usually found after large consumption of alcohol or meat, or post surgery. Autoimmune diseases like SLE, RA etc require an autoimmune screen.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 152
Incorrect
-
Carotid bodies...
Your Answer:
Correct Answer: Are located near the bifurcation of the carotid arteries bilaterally
Explanation:The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which runs along both sides of the throat).The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature. Carotid bodies trigger an action potential through the afferent fibers of the glossopharyngeal nerve,
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This question is part of the following fields:
- Medicine
- Respiratory
-
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Question 153
Incorrect
-
What is the most appropriate management of a DVT during pregnancy?
Your Answer:
Correct Answer: Heparin
Explanation:Low molecular weight heparin (LMWH) is safe in pregnancy and is therefore the first line management. Warfarin is teratogenic and must be avoided whilst the other options have no role to play.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 154
Incorrect
-
Among the following which is the beneficial effect of nitro-glycerine?
Your Answer:
Correct Answer: Dilation of systemic veins
Explanation:Dilation of systemic veins is a beneficial effect of nitro-glycerine.Administration of nitro-glycerine results in the dilation of systemic veins and decrease of myocardial wall tension and oxygen demand. Dilatation of systemic veins can cause reduced systemic vascular resistance leading to reduced cardiac workload thus reducing anginal symptoms secondary to demand ischemia.This is accompanied by vasodilation of large and medium-sized coronary arteries with increased coronary blood flow to the sub endocardium.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 155
Incorrect
-
All of the following are consistent with the indicator dilution method except---
Your Answer:
Correct Answer: In thermodilution, the indicator used is warm saline
Explanation:In thermodilution, the indicator used is cold saline.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 156
Incorrect
-
Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:
Your Answer:
Correct Answer: Weakening of the troponin i interaction with actin
Explanation:At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 157
Incorrect
-
A 23-year-old female known with schizophrenia is being reviewed in the emergency department. Her mother claims that she has been 'staring' for the past few hours but has now developed abnormal head movements and has gone 'cross-eyed'. On examination, the patient's neck is extended and positioned to the right. Her eyes are deviated upwards and are slightly converged. Given the likely diagnosis, what is the most appropriate treatment?
Your Answer:
Correct Answer: Procyclidine
Explanation:The most probable diagnosis in this patient is an oculogyric crisis, that is most appropriately managed with procyclidine or benztropine (antimuscarinic). An oculogyric crisis is a dystonic reaction to certain drugs or medical conditions.Features include:Restlessness, agitationInvoluntary upward deviation of the eyesCauses:PhenothiazinesHaloperidolMetoclopramidePostencephalitic Parkinson’s diseaseManagement:Intravenous antimuscarinic agents like benztropine or procyclidine, alternatively diphenhydramine or ethopropazine maybe used.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 158
Incorrect
-
The internodal tract of Bachman:
Your Answer:
Correct Answer: Connects the SA node to the AV node
Explanation:Internodal tract of Bachman connects the SA node to the AV node conducting the electrical impulses generated from the SA node to the AV node and from the AV node to the rest of the electrical complex of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 159
Incorrect
-
Select one true statement about haemoglobin synthesis…
Your Answer:
Correct Answer: Occurs in the cytosol of developing red cells.
Explanation:Haemoglobin (Hb) is synthesized in a complex series of steps. The haem part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 160
Incorrect
-
Where is the melanocortin system located?
Your Answer:
Correct Answer: Hypothalamus
Explanation:The melanocortin system is a group of hormones which include hormones from the pro-opiomelanocortin (POMC)-expressing neurons, the neuropeptide Y (NPY) and agouti-related peptide (AgRP)-co-expressing neurons. This system is located in the hypothalamic arcuate nucleus; it also includes the hypothalamic arcuate nucleus and the melanocortin 4 receptor (MC4R)-expressing neurons located in the hypothalamic paraventricular nucleus. The system regulates energy expenditure and food intake.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 161
Incorrect
-
A 16 year old previously well male presents with a 4 day history of fever, lethargy and a generalized macular rash. There is no significant previous medical history and the patient has not travelled abroad either. Vitals are as follows: Temp: 38.5BP: 125/75mmHgPulse: 100/min On auscultation the chest was clear and no heart murmur was heard. Examination also reveals a non blanching widespread macular rash over the chest and abdomen. There is swelling of interphalangeal joints of both hands and feet associated with mild tenderness. Lymph nodes are palpable over the supraclavicular, axillary and inguinal areas. Abdominal examination reveals palpable mass on both right and left hypochondrium. Lab results are given below:Haemoglobin (Hb) 13.5 g/dlWhite cell count (WCC) 14.0 × 109/lPlatelets 380 × 109/lSodium 145 mmol/lPotassium 4.8 mmol/lCreatinine 89 μmol/lRheumatoid factor NegativeAntinuclear antibody NegativeAnti-dsDNA NegativeASO titre Not detectedElectrocardiogram (ECG) Sinus rhythmWhat is the most likely underlying diagnosis?
Your Answer:
Correct Answer: Systemic Still’s disease
Explanation:People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 162
Incorrect
-
What microscopic changes are visible in an active thyroid gland?
Your Answer:
Correct Answer: Follicle lining cells are cuboid or columnar.
Explanation:Active follicles are lined by cuboidal or columnar cells; this is because active follicles are smaller and have less colloid. Their cells are tall because they are actively secreting hormones, whereas older follicles have a flat epithelium and are filled with more colloid.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 163
Incorrect
-
Which of these vitamins is not found in plants?
Your Answer:
Correct Answer: Vitamin B12
Explanation:No fungi, plants, nor animals (including humans) are capable of producing vitamin B12. Only bacteria and archaea have the enzymes needed for its synthesis. Proved food sources of B12 are animal products (meat, fish, dairy products).
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 164
Incorrect
-
Live active or attenuated vaccines:
Your Answer:
Correct Answer: Side effect may be egg hypersensitivity
Explanation:Live attenuated vaccines consist of a weakened form of the virus itself and have both advantages and disadvantages. Although they can exert an excellent immune response, potential risks exist. One such concern is the risk of reversion to a more virulent strain of virus. They are easily damaged or destroyed by heat and light, making it even more important that they be stored and refrigerated with care. Live vaccines are not given to immunocompromised persons. A few live vaccines against viruses include: oral polio, measles, mumps, rubella, rota virus and yellow fever. Eggs are used to produce Measles- mumps- rubella vaccine (MMR) and thus hypersensitivity may occur.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 165
Incorrect
-
Choose the most correct answer, what reduces affinity for oxygen in haemoglobin?
Your Answer:
Correct Answer: All the options are true
Explanation:The strength with which oxygen binds to haemoglobin is affected by several factors. These factors shift or reshape the oxyhaemoglobin dissociation curve. A rightward shift indicates that the haemoglobin under study has a decreased affinity for oxygen. The causes of shift to right can be remembered using the mnemonic, CADET, face Right! for CO2 and CO, Acid (H+), 2,3-DPG, Exercise and Temperature.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 166
Incorrect
-
An important hormone controlling the differentiation of monocytes to osteoclasts, by inhibiting the RANKL/ RANK interaction is called?
Your Answer:
Correct Answer: Osteoprotegerin
Explanation:Osteoprotegerin, also known as osteoclastogenesis inhibitory factor (OCIF) is a glycoprotein that acts as a cytokine receptor. It works as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoclast differentiation factor, thus inhibiting the differentiation of osteoclasts, which are capable of resorbing bone. Osteoprotegerin has been proposed as a therapeutic agent for osteoporosis.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 167
Incorrect
-
The triangle with the heart at its centre, using limb leads is called:
Your Answer:
Correct Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 168
Incorrect
-
Organophosphates, such as Sarin, have been used as chemical-warfare agents by terrorists. Which of the following statements is true concerning organophosphate poisoning?
Your Answer:
Correct Answer: Atropine is useful in the management of organophosphate poisoning
Explanation:The principal action of organophosphates is the inhibition of acetylcholinesterase’s, therefore leading to the accumulation of acetylcholine at muscarinic receptors (miosis, hypersalivation, sweating, diarrhoea, excessive bronchial secretions), nicotinic receptors (muscle fasciculations and tremor) and in the central nervous system (anxiety, loss of memory, headache, coma). Removal from the source of the organophosphate, adequate decontamination, supplemental oxygen and atropine are the initial treatment measures. Pralidoxime, an activator of cholinesterase, should be given to all symptomatic patients.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 169
Incorrect
-
Within the hypothalamus, the dopamine-secreting neurones of the intrahypothalamic system have their cell bodies in which nuclei?
Your Answer:
Correct Answer: Arcuate
Explanation:Arcuate nucleus dopaminergic neurons consist of a single group of neurons that project to the median eminence where they release dopamine into the hypophyseal portal circulation to inhibit pituitary prolactin secretion.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 170
Incorrect
-
Which vitamin is found in NAD and NADP?
Your Answer:
Correct Answer: Vitamin B3
Explanation:In organisms, NAD can be synthesized from simple building-blocks (de novo) from the amino acids tryptophan or aspartic acid. In an alternative fashion, more complex components of the coenzymes are taken up from food as the vitamin called niacin (vitamin B3)
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 171
Incorrect
-
An 18-year-old young lady is brought to the ER by her mother. She was found, lying on the floor having consumed an unidentified quantity of her mother's prescription pills with alcohol. The patient's mother is a known hypertensive under treatment. On examination, the patient was found to be lethargic, hypotensive with a BP of 70/50 mmHg, and bradycardic with a pulse rate of 38 bpm. A finger prick glucose is 3.2 mmol/L. Which TWO among the following are the most appropriate steps for the initial management of this patient?
Your Answer:
Correct Answer: Glucagon and isoprenaline
Explanation:The most appropriate steps of initial management include iv glucagon and iv isoprenaline.The most likely diagnosis in the above scenario (decreased conscious level, profound hypertension, and bradycardia) is β-blocker toxicity/overdose. Bronchospasm rarely occurs in an overdose of β-blockers, except where there is a history of asthma.Immediate management is to give iv glucagons (50–150μg/kg) followed by infusion to treat hypotension and isoprenaline or atropine to treat bradycardia. Where patients fail to respond to these measures, temporary pacing may be required. If the patient is seen within the first 4 hours of the overdose, gastric lavage may be of value.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 172
Incorrect
-
Majority of gastrinomas are found in the:
Your Answer:
Correct Answer: Duodenum
Explanation:A gastrinoma is a tumour in the pancreas or duodenum that secretes excess of gastrin leading to ulceration in the duodenum, stomach and the small intestine. It is usually found in the duodenum, although it may arise in the stomach or pancreas. Those occurring in the pancreas have a greater potential for malignancy. Most gastrinomas are found in the gastrinoma triangle; this is bound by the junction of cystic and common bile ducts, junction of the second and third parts of the duodenum, and the junction of the neck and body of the pancreas.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 173
Incorrect
-
Sequence of events in formation of speech are:
Your Answer:
Correct Answer: Wernicke’s area---arcuate fasciculus---broca’s area---insula---motor cortex---speech
Explanation:Wernicke’s area is located in the categorical hemisphere or left hemisphere in about 95% of right handed individuals and 60% of left handed individuals. It is involved in the comprehension or understanding of written and spoken language. In contrast Broca’s area is involved in production of language. Firstly, the language is accessed in the Wernicke’s area and these words are sent via the arcuate fasciculus to the Broca’s area, where instructions for articulation is generated. This is then sent from Broca’s are to the motor cortex for the articulation.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 174
Incorrect
-
Which of the following is true regarding platelets?
Your Answer:
Correct Answer: Normally have a half-life of about 8 days
Explanation:Platelets have no cell nucleus: they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow, and then enter the circulation. They have a half life of 5-9 days.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 175
Incorrect
-
Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer:
Correct Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 176
Incorrect
-
A 28 year old man presents to the clinic with fatigue, exertional dyspnoea, abdominal discomfort, xerophthalmia and xerostomia. Examination reveals enlargement of the parotid glands bilaterally, hepatomegaly and peripheral motor neuropathy. Lab results are negative for RF, ANA, SS-A and SS-B antibodies. What is the most likely diagnosis?
Your Answer:
Correct Answer: Diffuse infiltrative lymphocytic syndrome (DILS)
Explanation:The Diffuse Infiltrative Lymphocytosis Syndrome (DILS) is a rare multisystemic syndrome described in HIV-infected patients. It is characterised by CD8(+) T-cell lymphocytosis associated with a CD8(+) T-cell infiltration of multiple organs. DILS is usually seen in uncontrolled or untreated HIV infection but can also manifest itself independently of CD4(+) T-cell counts. The syndrome may present as a Sjögren-like disease that generally associates sicca signs with bilateral parotiditis, lymphadenopathy, and extra glandular organ involvement. The latter may affect the lungs, nervous system, liver, kidneys, and digestive tract. Anomalies of the respiratory system are often identified as lymphocytic interstitial pneumonia. Facial nerve palsy, aseptic meningitis or polyneuropathy are among the more frequent neurological features. Hepatic lymphocytic infiltration, lymphocytic interstitial nephropathy and digestive tract lymphocytic infiltration account for more rarely noted complications. Sicca syndrome, organomegaly and/or organ dysfunction associated with polyclonal CD8(+) T-cell organ-infiltration are greatly suggestive of DILS in people living with HIV.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 177
Incorrect
-
The process by which DNA fragments are separated by gel and transferred onto a membrane sheet is called:
Your Answer:
Correct Answer: Southern blotting
Explanation:A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 178
Incorrect
-
The conversion of fructose to fructose 1-phosphate is catalysed by:
Your Answer:
Correct Answer: Fructokinase
Explanation:The first step in the metabolism of fructose is the phosphorylation of fructose to fructose 1-phosphate by fructokinase.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 179
Incorrect
-
A son has brought his 72-year-old mother to clinic. He is concerned about her short-term memory problems for the past 10 months. He has to remind her to take her medications and she has had two incidents of falling over in the last 10 months. Which of the following assists in the diagnosis of above condition?
Your Answer:
Correct Answer: Progressive loss of function
Explanation:The clinical presentation is dementia. To differentiate Alzheimer disease and vascular dementia, the progressive loss of function is important. Progressive loss of function is usually associated with vascular dementia and rest of the responses are associated with Alzheimer disease.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 180
Incorrect
-
A 74-year-old man who has been diagnosed with atrial fibrillation and heart failure is being started on digoxin. What is the mechanism of action of digoxin?
Your Answer:
Correct Answer:
Explanation:Digoxin works by inhibiting the Na+/K+ ATPase pump in cardiac myocytes. Here’s how it works:
- Inhibition of Na+/K+ ATPase: Digoxin binds to and inhibits the Na+/K+ ATPase pump, which is responsible for pumping sodium out of the cell and potassium into the cell.
- Increased intracellular sodium: Inhibition of this pump leads to an increase in intracellular sodium levels.
- Decreased activity of the sodium-calcium exchanger: The increased intracellular sodium reduces the activity of the sodium-calcium exchanger, which normally pumps calcium out of the cell in exchange for sodium.
- Increased intracellular calcium: As a result, intracellular calcium levels rise because less calcium is being extruded from the cell. The increased calcium is then stored in the sarcoplasmic reticulum.
- Enhanced contractility: During each action potential, more calcium is released from the sarcoplasmic reticulum into the cytoplasm, which enhances the contractility of the heart muscle (positive inotropic effect).
By increasing the force of contraction, digoxin helps improve cardiac output in patients with heart failure. Additionally, digoxin has vagomimetic effects, which can help control the heart rate in atrial fibrillation by increasing vagal tone and thereby reducing the conduction velocity through the atrioventricular node.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 181
Incorrect
-
A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.On examination, he is sweating, agitated and disorientated. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg. Blood investigations performed in the emergency department reveal:FBC: NormalU&E: NormalPlasma glucose: 4.6 mmol/l (3.6-6)Which of the following medications would be the most appropriate treatment for this man?
Your Answer:
Correct Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.Treatment:- The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam. – If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.- Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.- It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 182
Incorrect
-
A 50-year-old male presents to the ER allegedly claiming that he consumed a bottle of antifreeze. Which of the following symptoms is least likely to be associated with this kind of poisoning?
Your Answer:
Correct Answer: Hypertension
Explanation:Loss of vision after consumption of antifreeze is a characteristic presentation of methanol poisoning.
Pathophysiology of methanol toxicity: When ingested, methanol is absorbed rapidly via the gastrointestinal tract in less than 10 minutes. Methanol is not protein-bound and is absorbed directly into the total body water compartment. Metabolism occurs mainly in the liver through serial oxidation via alcohol dehydrogenase and aldehyde dehydrogenase but begins with alcohol dehydrogenase present in the gastric mucosa. Alcohol dehydrogenase oxidizes methanol to formaldehyde, and aldehyde dehydrogenase subsequently oxidizes formaldehyde to formic acid. Formic acid is the primary toxic metabolite that accounts for the associated anion gap metabolic acidosis and end-organ damage.
Clinical presentation: Patients who present within the first 12 to 24 hours following ingestion may appear normal, and this is described as the latent period. Nausea, vomiting, and abdominal pain subsequently ensue, followed by CNS depression and hyperventilation due to metabolic acidosis. Ocular symptoms associated with retinal toxicity are often evident in the form of blurry vision, decreased visual acuity, photophobia, and “halo vision.”
Treatment: Treatment options for methanol toxicity include supportive care, fomepizole (Antizole, 4-Methylpyrazole or 4MP), ethanol, dialysis, and folate.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 183
Incorrect
-
The rate of depolarisation of the sinus node membrane potential is modulated by all the following except:
Your Answer:
Correct Answer: Cardiac output
Explanation:Cardiac output has no effect on the depolarization of the pacemaker potential of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 184
Incorrect
-
A patient has been diagnosed with multi-drug resistant tuberculosis and is currently bring treated with rifampicin, isoniazid, and pyrazinamide. He is commenced on streptomycin.Which among the following is the most likely neurological side-effect of streptomycin?
Your Answer:
Correct Answer: Vestibular damage
Explanation:Vestibular damage is a neurological side effect of streptomycin.Streptomycin is an aminoglycoside bactericidal antibiotic. It is used in the treatment of tularaemia and resistant mycobacterial infections.The most common neurological side-effect is vestibular damage leading to vertigo and vomiting. Cochlear damage is less frequent and results in deafness. Other side-effects include rashes, angioneurotic oedema, and nephrotoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 185
Incorrect
-
A cohort study is being designed to look at the relationship between smoking and prostate cancer. What is the usual outcome measure in a cohort study?
Your Answer:
Correct Answer: Relative risk
Explanation:A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time. The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 186
Incorrect
-
The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer:
Correct Answer: Ia
Explanation:Muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is gamma motor neurone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 187
Incorrect
-
The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer:
Correct Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 188
Incorrect
-
Question 189
Incorrect
-
Question 190
Incorrect
-
The direct determinants of cardiac output are
Your Answer:
Correct Answer: Stroke volume and heart rate
Explanation:Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 191
Incorrect
-
What is the protective hexametric sequence at the ends of chromosomes called?
Your Answer:
Correct Answer: Telomere
Explanation:Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 192
Incorrect
-
A 33 year old female presents with dyspnoea, myalgia, arthralgia and a skin rash. The presence of which of the following antibodies would be the most specific for SLE?
Your Answer:
Correct Answer: Anti-Sm
Explanation:Anti-Sm antibodies are essential for diagnosis of SLE, especially in anti-dsDNA-negative patients. ANA are also found in 95% of the patients with SLE but they may also occur with other conditions like Juvenile inflammatory arthritis, chronic activity hepatitis, and Sjogren’s syndrome. Anti-Ro, although also found with SLE are more characteristic of Sjogren Syndrome. RF is usually associated with rheumatoid arthritis and cANCA with Wegener’s granulomatosis, Churg Strauss, and microscopic polyangiitis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 193
Incorrect
-
Functions of the glossopharyngeal nerve include the following except:
Your Answer:
Correct Answer: Proprioceptive input from muscles of the tongue and larynx
Explanation:The glossopharyngeal nerve is a mixed nerve consisting of both sensory and motor fibers. It has several branches and five distinct general functions:Branchial motor- Special visceral efferent- supplies the Stylopharyngeus muscle and superior constrictor muscle.Visceral motor- general visceral efferent- provides parasympathetic innervation of the parotid gland.Visceral sensory- general visceral afferent- carries visceral sensory information from the carotid sinus and carotid body.General sensory- general somatic afferent- provides general sensory information from the inner surface of the tympanic membrane, upper pharynx and posterior one third of the tongue.Visceral afferent- special visceral afferent- provides taste sensation from the posterior one third of the tongue including the circumvallate papillae.
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This question is part of the following fields:
- Medicine
- Neurology
-
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Question 194
Incorrect
-
In the presence of oxygen , lactate that was produced under anaerobic conditions is converted to:
Your Answer:
Correct Answer: Pyruvate
Explanation:Lactate can be used in two ways:Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells. Pyruvate is then directly used to fuel the Krebs cycle orConversion to glucose via gluconeogenesis in the liver and release back into circulation.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 195
Incorrect
-
A 20-year-old male presents to the emergency department about 4 hours after ingesting 20g of paracetamol. N-acetyl cysteine was started immediately. What is the mechanism of action of N-acetyl cysteine?
Your Answer:
Correct Answer: Replenishes glutathione
Explanation:N-acetylcysteine depletes glutathione reserves by providing cysteine, which is an essential precursor in glutathione production.Glutathione within the liver can normally detoxify these minuscule quantities of NAPQI and prevent tissue damage.N-acetylcysteine (NAC) is the mainstay of therapy for acetaminophen toxicity.Paracetamol overdose:The liver normally conjugates paracetamol with glucuronic acid/sulphate. During an overdose, the conjugation system becomes saturated leading to oxidation by cytochrome P450 (predominately CYP2E1) mixed-function oxidases. This produces a toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI).Normally glutathione acts as a defence mechanism by conjugating with the toxin forming the non-toxic mercapturic acid. If glutathione stores run-out, the toxin forms covalent bonds with cell proteins, denaturing them and leading to cell death.Other uses: In COPD, cystic fibrosis, and other lung conditions, nebulized NAC has mucolytic, anti-inflammatory, and antioxidant properties.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 196
Incorrect
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Where does most fat digestion begin?
Your Answer:
Correct Answer: Duodenum
Explanation:Digestion of some fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine (in the duodenum). The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 197
Incorrect
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Regarding the innervation of the cerebral blood vessels, postganglionic sympathetic neurons have their cell bodies in the:
Your Answer:
Correct Answer: Superior cervical ganglia
Explanation:The superior cervical ganglion (SCG) is a part of autonomic system which plays a major role in maintaining homeostasis of the body. This ganglion innervates structures in the head and neck and is the largest and the most superiorly located ganglion. The SCG provides sympathetic innervation to structures within the head, including the pineal gland, the blood vessels in the cranial muscles and the brain, the choroid plexus, the eyes, the lacrimal glands, the carotid body, the salivary glands, and the thyroid gland. The postganglionic axons of the SCG innervate the internal carotid artery and form the internal carotid plexus. The internal carotid plexus carries the postganglionic axons of the SCG to the eye, lacrimal gland, mucous membranes of the mouth, nose, and pharynx, and numerous blood-vessels in the head.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 198
Incorrect
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Osteopetrosis occurs as a result of a defect in:
Your Answer:
Correct Answer: Osteoclast function
Explanation:It is a metabolic bone disease caused by defective osteoclastic resorption of immature bone. Osteopetrosis is also known as marble bone disease. Osteoclasts are unable to adequately acidify bone matrix. Impaired bone resorption leads to overly dense bone that is more likely to fracture. It is usually treated with bone marrow transplant and high dose calcitriol.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 199
Incorrect
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Which of the following conditions is least likely to exhibit the Koebner phenomenon?
Your Answer:
Correct Answer: Lupus vulgaris
Explanation:The Koebner phenomenon refers to skin lesions appearing on lines of trauma, exposure to a causative agents including: molluscum contagiosum, warts and toxicodendron dermatitis or secondary to scratching rather than an infective or chemical cause include vitiligo, psoriasis, lichen planus, lichen nitidus, pityriasis rubra pilaris, and keratosis follicularis (Darier disease).
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 200
Incorrect
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A 33-year-old electrical technician presents following an overdose. Anticholinergic syndrome is suspected. Which of the following is true?
Your Answer:
Correct Answer: Mydriasis occurs
Explanation:Anticholinergic syndrome occurs following overdose with drugs that have prominent anticholinergic activity including tricyclic antidepressants, antihistamines and atropine. Features include dry, warm, flushed skin, urinary retention, tachycardia, mydriasis (dilated pupils) and agitation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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