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Question 1
Correct
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The midbrain, medulla and pons, contain the following cranial nerve nuclei?
Your Answer: CN 3 - 12
Explanation:The cranial nerves (with the exception of I and II) originate in the brainstem, which includes the midbrain, the pons, and the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 2
Correct
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Microtubule disassembly:
Your Answer: Occurs at the positive and negative end
Explanation:Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region. Although both assembly and disassembly occur at both ends they occur preferentially at the (+) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 3
Correct
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HCL is secreted by which cells in the stomach
Your Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 4
Incorrect
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The following are examples of the functions of the vascular endothelium except:
Your Answer: Prothrombotic
Correct Answer: Tumour suppression
Explanation:Vascular endothelium has many important functions including regulation of vascular tone, molecular exchange between blood and tissue compartments, hemostasis and signaling for the immune regulation and inflammation. Depending on specific tissue needs and local stresses, endothelial cells are capable of evoking either antithrombotic or prothrombotic events. Tumor suppression is related to genes, or anti-oncogenes, that regulate a cell during cell division and replication.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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On which chromosome is the gene for insulin located?
Your Answer: Chromosome 11
Explanation:Humans have 23 pairs of chromosomes, and usually, two pairs of copies of chromosome 11. It is one of the most complex, gene-rich chromosomes in the human genome, and it is associated with a number of diseases. Studies have shown they the human insulin gene is located on the short arm of chromosome 11.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 6
Incorrect
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Question 7
Correct
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Where would one normally find venous valves?
Your 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 8
Correct
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Presence of which of the following indicates a worse prognosis in rheumatoid arthritis?
Your Answer: Anti-CCP antibodies
Explanation:Rheumatoid arthritis is both common and chronic, with significant consequences for multiple organ systems. Anti-cyclic citrullinated peptide (anti-CCP) antibody testing is particularly useful in the diagnosis of rheumatoid arthritis, with high specificity, presence early in the disease process, and ability to identify patients who are likely to have severe disease and irreversible damage. However, its sensitivity is low, and a negative result does not exclude disease. Anti-CCP antibodies have not been found at a significant frequency in other diseases to date, and are more specific than rheumatoid factor for detecting rheumatoid arthritis. The other factors that are mentioned do not play a key prognostic role.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 9
Correct
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Which afferent information is carried by the dorsal column?
Your Answer: Proprioception/ discriminative touch
Explanation:The posterior grey column (dorsal column) is responsible for carrying the sensation of proprioception, two-point discrimination, and vibration to the nucleus proprius, situated anterior to the substantia gelatinosa throughout the spinal cord.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 10
Incorrect
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A 39 year old woman with a history of rheumatoid arthritis has recently been switched from methotrexate to leflunomide. Monitoring of full blood count and LFTs has been carried out. Which of the following parameters should also be monitored in this case?
Your Answer: QT interval on ECG
Correct Answer: Blood pressure
Explanation:Blood pressure should be routinely measured as leflunomide may cause hypertension and thus an increase in BP. It doesn’t cause changes in blood sugar levels, peak expiratory flow rate or haematuria.
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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
Incorrect
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Which mechanism of action does Trimethoprim use?
Your Answer: Inhibit RNA polymerase
Correct Answer: Inhibit Folic Acid metabolism
Explanation:Trimethoprim binds to dihydrofolate reductase and inhibits the reduction of dihydrofolic acid (DHF) to tetrahydrofolic acid (THF). THF is an essential precursor in the thymidine synthesis pathway and interference with this pathway inhibits bacterial DNA synthesis.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 13
Incorrect
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Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer: Monocytes
Correct Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
Correct
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Which of the following is false with regard to the following statement: Proto- oncogenes can be transformed to oncogenes in the following ways.
Your Answer: Inhibition of P53
Explanation:Proto oncogenes cannot be transformed into oncogenes due to inhibition of P53 gene. There has to be a mutation in the proto oncogene. All the other options are true.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 15
Incorrect
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Question 16
Correct
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Which of the following is an incorrect statement regarding the structure of DNA?
Your Answer: The two strands of DNA are held together by cysteine bonds.
Explanation:The two strands of DNA are held together by hydrogen bonds formed between the nucleotide bases.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 17
Incorrect
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The liver is the principal site for?
Your Answer: Synthesis of immunoglobulins
Correct Answer: Storage of iron
Explanation:The liver mainly synthesizes proteins including albumin, globulins and coalgulative factors. Vitamin B12 is taken in via the diet and stored by the liver. Vitamin C is not stored and excessive vitamin C is excreted via urine. Liver is the main site of iron storage, where it is stored in the form of ferritin.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 18
Correct
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Regarding CSF:
Your Answer: Disruption of arachnoid villi function results in a communicating hydrocephalus
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of the entire volume of cerebrospinal fluid is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has different electrolyte levels. Blockage of the foramina causes an obstructive or non-communicating hydrocephalus. Communicating hydrocephalus or non-obstructive hydrocephalus is caused by impaired CSF reabsorption in the absence of any CSF flow obstruction.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 19
Correct
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An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?
Your Answer: It is contraindicated in hyperthyroidism
Explanation:The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 20
Correct
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A 32 year old woman presents with a painful elbow which she has been feeling for the past two weeks. Which of the following will be consistent with a diagnosis of tennis elbow?
Your Answer: Pain on wrist extension against resistance
Explanation:Lateral epicondylitis (tennis elbow) is an overuse injury of the hand and finger extensor tendons that originate in the lateral humeral epicondyle that occurs following repeated or excessive pronation/supination and extension of the wrist (e.g., in racquet sports). Clinical features include pain and tenderness over the lateral epicondyle and along extensor muscles and thickening of the tendons. The examiner holds the patient’s hand with the thumb placed over the lateral epicondyle – The patient makes a fist, supinates the forearm, deviates radially, and extends the fist against the examiner’s resistance which will result in pain over the lateral epicondyle. Conservative treatment includes rest, physiotherapy and orthotic braces. If this fails corticosteroids and lidocaine injections are employed. Surgery is indicated in patients with persistent symptoms despite 6 months of conservative treatment. Excision of abnormal tendon tissue; longitudinal incisions (tenotomies) in scarred and fibrotic areas to promote healing.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 21
Correct
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Which of the following runs in the upper part of the falx cerebri?
Your Answer: Superior sagittal sinus
Explanation:Falx cerebri is a sickle cell fold of dura between the two hemispheres. Its posterior part blends with the superior part of the tentorium cerebelli. The superior sagittal sinus runs in its upper fixed margin, the inferior sagittal sinus in the free concave margin and the straight sinus along its attachment to the tentorium cerebelli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 22
Correct
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A deficiency in Niacin leads to which clinical deficiency syndrome?
Your Answer: Pellagra
Explanation:Pellagra is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhoea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time affected skin may become darker, stiff, begin to peel, or bleed.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 23
Correct
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Which one of the following transporters is involved in facilitated diffusion?
Your Answer: GLUT2
Explanation:GLUT 2 is a bidirectional transporter, allowing glucose to flow in 2 directions via facilitated diffusion. Is expressed by renal tubular cells, liver cells and pancreatic beta cells. It is also present in the basolateral membrane of the small intestine epithelium.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 24
Correct
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The following are synthesized in the liver EXCEPT?
Your Answer: Cholecystokinin
Explanation:The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow. The liver also produces albumin, the most abundant protein in blood serum and angiotensinogen. Cholecystokinin, previously called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 25
Correct
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Regarding the length of systole and diastole which of the following is true?
Your Answer: The duration of systole is more fixed than diastole
Explanation:The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of systole remains more or less the same however, diastole decreases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Correct
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Question 27
Correct
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On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your 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.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Incorrect
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In which phase do chromosomes in the nucleus become completely condensed into well-defined chromosomes?
Your Answer: Prophase
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 29
Correct
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Which one of the following nerve fibers has the fastest conduction velocity?
Your Answer: α fiber
Explanation:α nerve fibers are characterized by being highly myelinated, which confers them with fast conduction properties. They innervate extrafusal skeletal muscle fibers, and their conduction velocity is between 80-120 m/s.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 30
Correct
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Into how many functional units can the cerebellum be divided?
Your Answer: 3
Explanation:The functional division of the cerebellum are the: Vestibulocerebellum (floculonodular lobe), Spinocerebellum (vermis and associated areas in the midline) and cerebrocerebellum (lateral hemispheres).
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This question is part of the following fields:
- Medicine
- Neurology
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Question 31
Incorrect
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Which of the toxin secretion pathways in the cell membrane of gram– bacteria delivers the toxin extracellular in a 2 stage process to the host?
Your Answer: III
Correct Answer: II
Explanation:Gram negative bacteria contain two membranes and there are about six specialized secretion systems. The secreted proteins play a key role in pathogenesis. Type II secretion systems (T2SS) are conserved in most Gram-negative bacteria, where they transport proteins from the periplasm into the extracellular environment. Because the T2SS channel is only found in the outer membrane, proteins secreted through this apparatus must first be delivered to the periplasm via the Sec or Tat secretion pathways and then to the extracellular environment making it a two-stage process.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 32
Correct
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A 72 year old retired fisherman presents with weakness of shoulders and hips over the last four months. Finger flexion is also weak but the extension is normal. There has been some difficulty swallowing liquids. Past medical history is not significant except for sexually transmitted disease that he caught some 40 years ago in South Pacific and got treated with antibiotics. He smokes and drinks one or two tots of rum at the weekend. Creatine kinase level is 125. Which of the following investigations is most significant in establishing a diagnosis?
Your Answer: Muscle biopsy with electron microscopy
Explanation:Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 33
Correct
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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: 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 34
Correct
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Anti-gastroesophageal reflux mechanisms include the following except:
Your Answer: Peristaltic movements of the oesophagus
Explanation:The lower oesophageal sphincter contracts preventing reflux of acid into the oesophagus. The sling muscles of the stomach, the crura of the diaphragm and the phreno-oesophageal ligament all play an important role in constricting the lower portion of the oesophagus and preventing reflux. Peristaltic movements do not stop the acid reflux.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 35
Correct
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The rate of depolarisation of the sinus node membrane potential is modulated by all the following except:
Your 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 36
Incorrect
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Which of the following conditions results from chromosomal ‘non-disjunction’?
Your Answer: Down syndrome
Correct Answer: All of the options
Explanation:Non-disjunction can result in aneuploidy i.e. abnormal number of chromosomes in a cell. It results due to uneven division of chromosomes in the meiosis 1 or 2 phase. All the above mentioned examples are of non-disjunction.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 37
Incorrect
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A patient with achalasia
Your Answer: increased peristalsis in the oesophagus
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 38
Correct
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Which of the following skin conditions is not associated with diabetes mellitus?
Your Answer: Sweet's syndrome
Explanation:Diabetic dermadromes constitute a group of cutaneous conditions commonly seen in people with diabetes with longstanding disease. Conditions included in this group are:- Acral dry gangrene- Carotenosis- Diabetic dermopathy- Diabetic bulla- Diabetic cheiroarthropathy- Malum perforans- Necrobiosis lipoidica- Limited joint mobility- Scleroderma- Waxy skin is observed in roughly 50%. Sweet’s syndrome is also known as acute febrile neutrophilic dermatosis has a strong association with acute myeloid leukaemia. It is not associated with diabetes mellitus.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 39
Correct
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Three adjacent nucleotides code for a particular amino acid. These are called codons. How many common amino acids are there and how many potential codon combinations make up the genetic code?
Your Answer: 20 amino acids, 64 codon combinations
Explanation:There are around 20 amino acids and 61 out of the 64 combinations of codon code for these 20 common amino acids.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 40
Correct
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Which ventral (motor) root is responsible for triceps?
Your Answer: C7
Explanation:Of the nerve fibers that make up the brachial plexus, C7 mainly forms the radial nerve to innervate the triceps muscle, thus innervating the shoulders, elbow, wrist and hand. C7 is responsible for the triceps reflex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 41
Correct
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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: 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 42
Correct
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Which of the following is NOT a component of bile?
Your Answer: Unconjugated bilirubin
Explanation:The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts (electrolytes).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 43
Correct
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The primary auditory cortex is:
Your Answer: Brodmann area 41
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary Sensory 3,1,2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 44
Correct
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Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer: 5α-reductase
Explanation:The enzyme 5α-reductase synthesizes DHT from testosterone in the prostate, testes, hair follicles, and adrenal glands. This enzyme reduces the 4,5 double-bond of the testosterone. Relative to testosterone, DHT is much more potent as an agonist of the androgen receptor.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 45
Incorrect
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Where are the cell bodies of preganglionic neurons located?
Your Answer: Dorsal root
Correct Answer: Lateral column
Explanation:The cell bodies of the preganglionic neurons are located in the lateral grey column of the spinal cord and in the motor nuclei of the 3rd, 7th, 9th and 10th cranial nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 46
Correct
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The pyloric sphincter is largely made up of thickening of
Your Answer: The circular muscle layer
Explanation:The pyloric sphincter, or valve, is a strong ring of smooth muscle (circular muscle layer) at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum. It receives sympathetic innervation from the celiac ganglion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 47
Correct
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The thalamus is a large collection of neuronal groups within the diencephalons which participates in:
Your 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 48
Incorrect
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Which one of the following cells originates from a monocyte and resembles a macrophage?
Your Answer: Astrocyte
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 49
Correct
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In response to tissue injury, which of these cannot sensitize and activate nociceptors?
Your Answer: Calcium
Explanation:Histamine, serotonin, bradykinin and prostaglandin are all chemical mediators of inflammation with different distinct functions however all activate nociceptors. Calcium on the other hand cannot sensitize or activate nociceptors.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 50
Correct
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Which of the following structures lie in close proximity to the thyroid?
Your Answer: All of the options
Explanation:The thyroid gland receives its blood supply from the inferior and superior thyroid arteries. The recurrent laryngeal nerves emerges from the superior thoracic outlet bounded in part by the thyroid lobe. Two pairs of parathyroid glands lie near the thyroid. The common carotid artery splits into its external and internal branches at the upper border of the thyroid cartilage; these branches are separated by the gland.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 51
Correct
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Stimulation of the carotid sinus results in:
Your Answer: Drop in blood pressure
Explanation:Stimulation of the carotid sinus will result in an increase in the baroreceptor discharge. This will travel via the afferent nerves to the medulla. Signals will pass through the vagus nerve to decrease the sympathetic outflow to the heart and the blood vessels. This inhibition will result in vasodilation of the blood vessels, venodilation and bradycardia hence decreasing the total peripheral resistance and lowering the blood pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 52
Correct
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The structure of haemoglobin A in adults includes
Your Answer: Haem, globin polypeptide chains α and β
Explanation:Haemoglobin A (HbA), also known as adult haemoglobin or α2β2, is the most common human haemoglobin tetramer, comprising over 97% of the total red blood cell haemoglobin. It consists of two alpha chains and two beta chains.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 53
Correct
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Which of the following describes a principal action of insulin?
Your Answer: Inhibition of phosphorylase and gluconeogenic enzymes
Explanation:Insulin stimulates glycolysis and lipogenesis, but inhibits gluconeogenesis. Insulin promotes the dephosphorylating of glycogen phosphorylase, therefore suppressing glycogenolysis. Insulin also inhibits FOX3, FOX4, and FOX6 and their ability to promote hepatic gluconeogenesis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 54
Correct
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What is the function of basic electrical rhythm
Your Answer: To coordinate peristalsis and other motor activity
Explanation:The basal or basic electrical rhythm (BER) or electrical control activity (ECA) determines the frequency of the contractions in the gastrointestinal (GI) tract, thus acting to coordinate peristalsis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 55
Incorrect
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Type 2 hypersensitivity is mediated by:
Your Answer: IgA and complement
Correct Answer: IgG, IgM & complement
Explanation:In type II hypersensitivity the antibodies, IgG and IgM bind to antigens to form complexes that activate the classical pathway of complement to eliminate cells presenting foreign antigens.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 56
Correct
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What is the primary cause of ketoacidosis in Type 1 diabetes?
Your Answer: Lipolysis
Explanation:in type 1 diabetics the lack of insulin in the bloodstream prevents glucose absorption, thereby inhibiting the production of oxaloacetate (a crucial precursor to the β-oxidation of fatty acids) through reduced levels of pyruvate (a by-product of glycolysis), and can cause unchecked ketone body production (through fatty acid metabolism or lipolysis) potentially leading to dangerous glucose and ketone levels in the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 57
Correct
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Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 58
Correct
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In Argyll Robertson pupils…
Your Answer: All of the options given
Explanation:Argyll Robertson pupils are bilaterally small pupils that accommodate or reduce in size near an object but do not react to light. They do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis but may be seen in diabetic neuropathy as well.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 59
Correct
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In paralytic ileus the following are true except:
Your Answer: Opioid blocking drugs will exacerbate the symptoms
Explanation:Paralytic ileus causes adynamic intestinal obstruction or decreased peristalsis and the most common reason being postoperative ileus. Opioid drugs like morphine are given for pain management and cause decreased peristalsis in the gut resulting in constipation. Theoretically opioid blocking drugs or opioid antagonists can increase peristalsis and can alleviate paralytic ileus symptoms.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 60
Correct
-
Vitamin K deficiency can be found in which of the following condition?
Your 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
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Question 61
Incorrect
-
Which one of the following skin disorders is least commonly associated with hypothyroidism?
Your Answer: Eczema
Correct Answer: Pretibial myxoedema
Explanation:Pretibial myxoedema is an infiltrative dermopathy, resulting as a rare complication of Graves’ disease (hyperthyroidism) and very occasionally occurs in non-thyrotoxic Graves’ disease and Hashimoto’s thyroiditis.
Hypothyroidism typically presents with symptoms such as dry skin, brittle hair, and thinning of the outer third of the eyebrows. While skin conditions like dryness and hair changes are common in hypothyroidism due to reduced metabolic activity, acne is also not typically associated with it.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 62
Incorrect
-
Which statement about antithrombin III is true?
Your Answer: It inactivates factors V and VIII
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 63
Incorrect
-
Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer: Myeloperoxidase converts br/i/cl to acids
Correct Answer: NADPh oxidase
Explanation:Catalase Degrades H2O2 to H20 and O2, Superoxide Dismutase Forms H2O2, Myeloperoxidase Converts Br/I/Cl to acids
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This question is part of the following fields:
- Immunology
- Medicine
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Question 64
Correct
-
Preload:
Your Answer: Is the degree to which the myocardium is stretched before is contracts
Explanation:Preload is end diastolic volume. It is the degree to which the heart muscle fiber is stretched when it fills up completely just before the heart contracts.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 65
Correct
-
Which of the following hormones would stimulate secretion of TSH?
Your Answer: TRH
Explanation:Thyrotropin-releasing hormone, also known as TRH, thyrotropin-releasing factor, TRF is a hormone produced by the hypothalamus. It functions as a releasing hormone, promoting the production of thyroid-stimulating hormone or thyrotropin and prolactin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 66
Correct
-
The enzyme responsible for Telomeres to maintain their length after cell division is called:
Your Answer: Telomerase reverse transcriptase
Explanation:Telomeres are non-coding DNA consisting of repetitive nucleotide sequences 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 67
Incorrect
-
An 80 year old female, previously diagnosed with polymyalgia rheumatica 18 months back, presents to the outpatient clinic with bilateral shoulder stiffness and generalized myalgia. The ESR was found to be 60mm/1st hour at the time of presentation. Prednisolone therapy was initiated at a daily dose of 15 mg along with Calcium and Vitamin supplementation. She reported resolution of her symptoms in one week. However the symptoms relapsed when the prednisolone dose was reduced below the current dose of 12.5 mg daily. How should she be ideally managed?
Your Answer: Increase the dose of prednisolone and add a bisphosphonate
Correct Answer: Continue the current dose of prednisolone and start methotrexate
Explanation:Polymyalgia rheumatica, a syndrome characterized by proximal muscle pain and stiffness in older persons, generally is treated with prednisone. Dosages of 15 to 25 mg of prednisone per day can reduce inflammation considerably, although many patients relapse when therapy is tapered. Long-term (18 to 36 months) steroid treatment has been recommended by several studies, but this can result in multiple side effects, including osteoporosis, hypertension, cataracts, and hyperglycaemia. Methotrexate has been used to reduce inflammation in rheumatoid arthritis, systemic vasculitis, and giant cell arteritis, and in some studies has been combined with prednisone to treat polymyalgia rheumatica, decreasing the duration of treatment.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 68
Incorrect
-
Which one of the following is a risk factor for torsade de pointes?
Your Answer: Hypercalcaemia
Correct Answer: Hypothermia
Explanation:The following is a list of factors associated with an increased tendency toward torsades de pointes:- Hypokalaemia (low blood potassium)- Hypomagnesemia (low blood magnesium)- Hypocalcaemia (low blood calcium)- Bradycardia (slow heartbeat)- Heart failure- Left ventricular hypertrophy- Hypothermia- Subarachnoid haemorrhage- Hypothyroidism
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 69
Incorrect
-
Which vitamin plays a major role in the metabolism of many amino acids?
Your Answer: Vitamin B12
Correct Answer: Vitamin B6
Explanation:Vitamin B6 is part of the vitamin B group, and its active form, pyridoxal 5′-phosphate (PLP) serves as a coenzyme in many enzyme reactions in amino acid, glucose, and lipid metabolism.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 70
Correct
-
In cardiac muscle, which of the following is directly responsible for the release of Ca2+ stored in the sarcoplasmic reticulum (calcium-induced calcium release)?
Your Answer: Ryanodine receptor (RyR)
Explanation:Ryanodine receptor (RyR) is a ligand-gated Ca2+ channel with Ca2+ as its natural ligand. In skeletal muscle, Ca2+ entry from ECF by this route is not required for Ca2+ release. Instead, the DHPR that serves as the voltage sensor unlocks release of Ca2+ from the nearby SR via physical interaction with the RyR. The release is amplified through ca-induced ca release. However, in cardiac muscle, it is the influx of extracellular Ca2+ through the voltage-sensitive DHPR in the T system that triggers ca-induced ca release trough the RyR at the SR.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 71
Correct
-
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 72
Correct
-
Question 73
Correct
-
Which one of the following is necessary to activate plasminogen to plasmin?
Your Answer: tPA
Explanation:In circulation, plasminogen adopts a closed, activation resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 74
Incorrect
-
With regards to environmental temperature, for each degree Celsius of elevation, the metabolic rate rises?
Your Answer: 0.2
Correct Answer: 0.14
Explanation:An increase in body temperature is associated with a higher metabolic rate. Evidence suggests that an increase of 1°C in your body temperature increases your metabolism by 10 to 14%.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 75
Correct
-
The residual cleft of the intermediate lobe of the pituitary is lined by follicles resembling which human gland?
Your Answer: Thyroid
Explanation:The cells located between the two main pituitary lobes form what is known as the intermediate pituitary. This area secretes melanocyte-stimulating hormone and it is only a few cell layers thick. It is rich in follicles filled with colloid, and lined by basophilic cells. This configuration resembles that of another important gland: the thyroid.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 76
Correct
-
The brainstem contains which of the following structures?
Your Answer: The midbrain, pons and medulla
Explanation:Brain stem is the base of the brain that connects the brain to the spinal cord. It consists of the mid brain, pons and medulla oblongata.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 77
Incorrect
-
The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer: IIa
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 78
Incorrect
-
Critical shortening of Telomeres result in:
Your Answer: Activation of p 53 and prb and cell crisis
Correct Answer: Inactivation of p 53 and prb and cell crisis
Explanation:Telomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 79
Incorrect
-
As assessed by immunocytochemistry and electron microscopy, the anterior pituitary gland contains how many different types of cells?
Your Answer: 8
Correct Answer: 5
Explanation:The pituitary is divided into three sections
-the anterior lobe which constitute the majority of the pituitary mass and is composed primarily of five hormone-producing cell types (thyrotropes, lactotropes, corticotropes, somatotropes and gonadotropes) each secreting thyrotropin, prolactin, ACTH, growth hormone and gonadotropins (FSH and LH) respectively.
There is also a sixth cell type in the anterior lobe -the non-endocrine, agranular, folliculostellate cells.
The intermediate lobe produces melanocyte-stimulating hormone and endorphins, whereas the posterior lobe secretes anti-diuretic hormone (vasopressin) and oxytocin.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 80
Incorrect
-
The following determines the strength of contraction
Your Answer: Resting membrane potential
Correct Answer: Plateau phase
Explanation:The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 81
Incorrect
-
Neutrophils are attracted to an infected area by:
Your Answer: Cytokines
Correct Answer: Chemokines
Explanation:The major role of chemokines is to act as a chemoattractant to guide the migration of cells like neutrophils to the site of infection.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 82
Correct
-
In meiosis, the period of prophase 1 involves:
Your Answer: Replicated DNA condensing to form visible chromosomes
Explanation:Prophase 1 has been divided into five different stages (laptotene, zygotene, pachytene, diplotene and diakinesis). In prophase 1, chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 83
Correct
-
Peristalsis is an example of:
Your Answer: Enteric nervous system
Explanation:Peristalsis is a type of contraction where radial symmetrical contraction and relaxation of muscles propagates food in a downward wave through the gut. The enteric nervous system is one of the main divisions of the nervous system and consists of a mesh-like system of neurons that controls the function of the gastrointestinal tract. It has an independent reflex activity. The neurons of this system re collected into two types of ganglia: myenteric (or Auerbach’s) and submucosal (or Meissner’s plexuses). Myenteric plexuses are located between the inner and outer layers of the muscularis externa, while submucosal plexuses are located in the submucosa.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 84
Correct
-
In which cell would you find a Nissl body?
Your Answer: Bipolar neuron
Explanation:Nissl bodies are the structures of protein synthesis in neurones. They are granular bodies of Rough Endoplasmic Reticulum and ribosomes. Astrocytes, Microglia, Schwann cell, oligodendrocytes are collectively known as glia or supporting cells of the nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 85
Correct
-
Myocardial contractility is improved by:
Your Answer: Caffeine
Explanation:Caffeine and other theophyllines breakdown cAMP and have a positive ionotropic effect on the heart. Drugs like quinidine, procainamide and conditions like hypoxia and hypercapnia decreases the contractility of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 86
Incorrect
-
The cells that secrete HCL are found in which part of the stomach?
Your Answer: Antrum
Correct Answer: Body
Explanation:The stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Different cell types are distributed accordingly among the regions of the stomach. Cells that secret HCl in the gastric mucosa are known as parietal cells and are abundant in the gastric body region. They have receptors for acetylcholine stimulated via the vagus nerve, histamine receptors and gastrin receptors which stimulate gastric acid secretion. G cells that secret gastrin are abundant in the antrum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
-
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Question 87
Correct
-
Which of the following stimulates glucagon release?
Your Answer: Exercise
Explanation:Studies have shown a small increase in glucagon levels during stress tests and exercise. This occurs in response to the reduction of blood glucose levels during physical activity; epinephrine levels are also a stimulus for the release of glucagon during exercise, since it suppresses insulin, which accounts for its stimulatory effects on glucagon. The use of stored fats for energy during exercise also stimulates the release of glucagon.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 88
Incorrect
-
Endotoxin
Your Answer: Has four specialized secretion pathways
Correct Answer: Composed of Lipid A in liposaccharide in cell wall
Explanation:Lipopolysaccharides (LPS), also known as lipoglycans and endotoxins, are large molecules consisting of a lipid (lipid A) and a polysaccharide composed of O-antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, and elicit strong immune responses in animals.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 89
Correct
-
Di and tri peptides are absorbed via a different mechanism as amino acids, this is due to the working of which transporter?
Your Answer: PEPT 1
Explanation:GLUT and SGLT are glucose transporters. Peptides which are longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cells of the small intestine via a transporter called PepT1 by co-transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 90
Incorrect
-
A 24 year old male, known case of hereditary angioneurotic oedema presents with recurrent fever and arthralgia which is accompanied by a rash on face and upper chest. These attacks have been refractory to treatment and have occurred recurrently requiring adrenaline on several occasions. Lab results reveal persistently reduced C4 levels. Which of the following is most likely causing his current symptoms?
Your Answer: Viral illness
Correct Answer: Systemic lupus erythematosus
Explanation:Angioedema secondary to C1 inhibitor deficiency has been rarely reported to be associated with systemic lupus erythematosus. A genetic defect of C1 inhibitor produces hereditary angioedema, which is usually presented with cutaneous painless oedema, but oedema of the genital area, gastrointestinal and laryngeal tracts have also been reported. In lupus patients, angioedema may be the result of an acquired type of C1 inhibitor deficiency, most probably due to antibody formation directed against the C1 inhibitor molecule.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 91
Correct
-
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 92
Incorrect
-
The enzyme located on the brush border of the small intestine activating the proteolytic enzymes for further digestion of proteins is called?
Your Answer: Trypsin
Correct Answer: Enterokinase
Explanation:Enterokinase is a brush border enzyme of the duodenum that activates proteolytic enzymes for further digestion of proteins. Trypsinogen is converted to trypsin by the action of enterokinase. Trypsin and chymotrypsin are secreted by the pancreatic acinar cells and are enzymes that aid in protein digestion. Pepsin is secreted by chief cells of the gastric mucosa. Procarboxydase is the inactive form of carboxypeptidase which is converted to its active form by trypsin and is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 93
Correct
-
Which of the following is true with AV nodal delay?
Your Answer: Shortened by sympathetic stimulation
Explanation:AV nodal delay Is about 0.1s before the action potential spreads to the ventricles. It is shortened by stimulation of the sympathetic nervous system and lengthened by stimulation of the parasympathetic system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 94
Correct
-
A 30-year-old woman is admitted for drainage of an abscess in her left forearm. She has revealed that she was regular heroin user and has stopped for the past few days. Clinical signs are pointing towards opioid withdrawal. What is the next step in managing this patient?
Your Answer: Give her 10 mg of methadone syrup and wait 60 min to determine its effect
Explanation:The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.Methadone should be used with caution if the patient has:Respiratory deficiencyAcute alcohol dependenceHead injuryTreatment with monoamine oxidase inhibitors (MAOIs)Ulcerating colitis or Crohn’s diseaseSevere hepatic impairmentThe dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms. To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given. It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 95
Correct
-
Angina pectoris develops when blood through the coronary artery becomes:
Your Answer: Restricted, limiting blood blow
Explanation:Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 96
Correct
-
A 18-year-old girl is brought to A&E having ingested at least 16 tablets of paracetamol 8 hours earlier. What should her immediate management consist of?
Your Answer: Intravenous N-acetylcysteine
Explanation:Activated charcoal is useful if given within one hour of the paracetamol overdose. Liver function tests, INR and prothrombin time will be normal, as liver damage may not manifest until 24 hours or more after ingestion.The antidote of choice is intravenous N-acetylcysteine, which provides complete protection against toxicity if given within 10 hours of the overdose.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 97
Correct
-
With regards to splenic micro-architecture which is not contained within the red pulp
Your Answer: Malpighian corpuscles
Explanation:Red pulp is responsible for mechanical filtration of red blood cells and is composed of sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zone bordering on white pulp. White pulp provides an active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths (PALS), rich in T-lymphocytes.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 98
Incorrect
-
The cerebellum consists of which three cell layers?
Your Answer: Granular, purkinje, stellate
Correct Answer: Granular, purkinje, molecular
Explanation:The cerebellar cortex consist of 3 layers; the molecular layer, the granular cell layer and the Purkinje cell layer in the middle.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 99
Incorrect
-
Which of the following forms an important constituent of the brush border on the microvilli of the intestinal epithelium?
Your Answer: Crypts
Correct Answer: Hydrolases
Explanation:There are certain enzymes which are part of the brush border cells including hydrolases also known as the brush border hydrolases. They perform the final step in digestion of certain nutrients.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 100
Correct
-
In the life cycle of plasmodium species:
Your Answer: Merozoites are released from the liver and enter the red blood cell
Explanation:Plasmodium is a genus of parasitic protozoa, many of which cause malaria in their hosts. The parasite always has two hosts in its life cycle: a Dipteran insect host and a vertebrate host. Sexual reproduction always occurs in the insect, making it the definitive host.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
-
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Question 101
Incorrect
-
An 18 year old girl presents with short history of marked, right hip pain and an associated limp. She has a history of acute lymphoblastic leukaemia for which she completed treatment for last six months.
Your Answer: Gout
Correct Answer: Avascular necrosis of the femoral head
Explanation:Avascular necrosis (AVN) of the femoral head is a pathological process that results from disruption of the blood supply to the bone and occurs most commonly in the femoral epiphysis. Patients usually present with pain and limited joint motion. The mechanism involves impaired circulation to a specific area that ultimately becomes necrotic. AVN is most frequently associated with high doses of oral and intravenous corticosteroids and prolonged duration of therapy. Cancer patients receiving chemotherapy are usually also treated with corticosteroids.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 102
Incorrect
-
What is the rationale concerning the use of sodium cromoglycate in the prophylaxis of bronchial asthma?
Your Answer: Inhibition of acetylcholine at the synaptic junctions
Correct Answer: Inhibition of mast-cell degranulation
Explanation:Sodium cromoglycate principally acts by inhibiting the degranulation of mast cells triggered by the interaction of antigen and IgE. The inhibitory effect on mast cells appears to be cell-type specific since cromoglycate has little inhibitory effect on mediator release from human basophils.Thus, it inhibits the release of histamine, leukotrienes, and slow-reacting substance of anaphylaxis from mast cells by inhibiting degranulation following exposure to reactive antigens.Adverse effects include cough, flushing, palpitation, chest pain, nasal congestion, nausea, fatigue, migraine, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 103
Correct
-
Question 104
Correct
-
A 35-year-old male presented to the ER after being rescued from a house fire. He complained of feeling dizzy and having a worsening headache. On examination, he was dyspnoeic, drowsy and confused. There was no evidence of facial burns and no stridor. He was normotensive, tachycardic (pulse rate: 102 bpm), tachypnoeic (respiratory rate: 35/min) and had O2 saturation of 100% in room air. His venous blood gas results are given below: pH - 7.28pCO2 - 3.5 kPapO2 - 15.9 kPaNa+ - 139 mmol/LK+ - 4.5 mmol/LBicarbonate - 11 mmol/LChloride - 113 mmol/LLactate - 13.6 mmol/LKeeping in mind the likely diagnosis, which among the following is the most appropriate intervention for this patient?
Your Answer: Intravenous hydroxocobalamin
Explanation:The most appropriate intervention in this patient is intravenous hydroxocobalamin.The clinical scenario provided is suggestive of acute cyanide toxicity secondary to burning plastics in the house fire. Cyanide ions inhibit mitochondrial cytochrome oxidase, preventing aerobic respiration. This manifests in normal oxygen saturations, a high pO2 and flushing (or ‘brick red’ skin) brought on by the excess oxygenation of venous blood. In the question above it is important to note that the blood gas sample given is venous rather than arterial. His blood gas also demonstrates an increased anion gap, consistent with his high lactate (generated by anaerobic respiration due to the inability to use available oxygen).The recommended treatment for moderate cyanide toxicity in the UK is one of three options: sodium thiosulfate, hydroxocobalamin or dicobalt edetate. Among the options given is hydroxocobalamin and this is, therefore, the correct answer. Hydroxocobalamin additionally has the best side-effect profile and speed of onset compared with other treatments for cyanide poisoning.Other options:- Intubation would be appropriate treatment in the context of airway burns but this patient has no evidence of these, although close monitoring would be advised. – High-flow oxygen is the treatment for carbon monoxide poisoning – a sensible differential, but this man’s very high lactate and high venous pO2 fit better with cyanide toxicity. Intravenous dexamethasone would be another treatment for airway oedema once an endotracheal tube had been placed. – Intravenous sodium nitroprusside is a treatment for high blood pressure that can cause cyanide poisoning, and would, therefore, be inappropriate.Note:Cyanide may be used in insecticides, photograph development and the production of certain metals. Toxicity results from reversible inhibition of cellular oxidizing enzymesClinical presentation:Classical features: brick-red skin, the smell of bitter almondsAcute: hypoxia, hypotension, headache, confusionChronic: ataxia, peripheral neuropathy, dermatitisManagement:Supportive measures: 100% oxygenDefinitive: hydroxocobalamin (intravenously), also a combination of amyl nitrite (inhaled), sodium nitrite (intravenously), and sodium thiosulfate (intravenously).
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 105
Correct
-
Café-au-lait spots are seen in each of the following, except:
Your Answer: Friedreich's ataxia
Explanation:Café-au-lait spots are hyperpigmented lesions that vary in colour from light brown to dark brown, with borders that may be smooth or irregular.
Causes include:
- Neurofibromatosis type I
- McCune–Albright syndrome
- Legius syndrome
- Tuberous sclerosis
- Fanconi anaemia
- Idiopathic
- Ataxia-telangiectasia
- Basal cell nevus syndrome
- Benign congenital skin lesion
- Bloom syndrome
- Chediak-Higashi syndrome
- Congenital nevus
- Gaucher disease
- Hunter syndrome
- Maffucci syndrome
- Multiple mucosal neuroma syndrome
- Noonan syndrome
- Pulmonary Stenosis
- Silver–Russell syndrome
- Watson syndrome
- Wiskott–Aldrich syndrome
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 106
Incorrect
-
A 50-year-old farmer, under treatment for depression, presents to the emergency department following an intentional overdose of an unidentified substance. On examination, he was found to be bradycardic, hypotensive, hyper-salivating, and disoriented. On ocular examination, his pupils were found to be miotic. What is the most likely substance he ingested?
Your Answer: A tricyclic antidepressant
Correct Answer: An organophosphate insecticide
Explanation:The farmer has most likely ingested an organophosphate insecticide.Organophosphorus compounds are used widely as:• Insecticides – Malathion, parathion, diazinon, dichlorvos• Nerve gases – Soman, sarin, tabun, VX• Ophthalmic agents – Echothiophate• Antihelmintics – Trichlorfon• Herbicides – merphos• Industrial chemical (plasticizer) – Tricresyl phosphateSigns and symptoms of Organophosphorus Poisoning (OPP) can be classified as:• Muscarinic effects:o Cardiovascular – Bradycardia, hypotensiono Respiratory – Rhinorrhoea, bronchorrhea, bronchospasm, cough, severe respiratory distresso Gastrointestinal – Hypersalivation, nausea and vomiting, abdominal pain, diarrhoea, faecal incontinenceo Genitourinary – Incontinenceo Ocular – Blurred vision, miosiso Glands – Increased lacrimation, diaphoresis• Nicotinic effects:o Muscle fasciculation, weakness, cramping, diaphragmatic failure, and autonomic side effects include: hypertension, tachycardia, and mydriasis.• Central nervous system (CNS) effects:o Anxiety, emotional lability, restlessness, confusion, ataxia, tremors, seizures, coma, apnoeaMainstay Treatment:• Decontamination• Securing Airway, Breathing and Circulation• Atropine• Pralidoxime• Benzodiazepines
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 107
Incorrect
-
Which of the following is true regarding platelets?
Your Answer: They exhibit chemo taxis
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 108
Correct
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Question 109
Correct
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A 26 year old woman is 32 weeks pregnant. She has a history of Sjogren Syndrome. The foetus would be at a risk for which of the following?
Your Answer: All correct
Explanation:Women with Sjögren syndrome are likely to experience more complications during pregnancy than women without an autoimmune disease as the anti-Ro and anti-La antibodies cross the placenta and lead to various life threatening complications. Studies show a high incidence of poor fetal outcomes for these patients. Congenital heart block, neonatal lupus, congestive cardiac failure, hydrops fetalis can all be caused as a result of Sjogren syndrome.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 110
Incorrect
-
The superior orbital fissure is the site of entry/exit for which of the following group of nerves?
Your Answer: CN II, III, V1, VI
Correct Answer: CN III, IV, V1, VI
Explanation:The superior and inferior divisions of oculomotor nerve (III), trochlear nerve (IV), lacrimal, frontal and nasociliary branches of ophthalmic V1 and the abducens nerve (VI)
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This question is part of the following fields:
- Medicine
- Neurology
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Question 111
Correct
-
A 68 year old male presented with swelling in the lower pole of his parotid gland. It is revealed that this has been ongoing for the past 10 years. Upon examination, the swelling is firm in consistency. From the list of options, choose the most probable diagnosis for this patient.
Your Answer: Pleomorphic adenoma
Explanation:A pleomorphic adenoma is also called a benign mixed tumour – this is the most common tumour of the parotid gland. It also causes over a third of all submandibular tumours. This type of a tumour is slow-growing and has no symptoms, which means it has great malignant potentiality.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 112
Correct
-
Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 113
Correct
-
“Ploidy” is a term used to refer to the number of chromosomes in cells. Cancer cells are commonly:
Your Answer: Aneuploidy
Explanation:Cancer cells most commonly undergo disordered cell growth and cell division. This results in an additional number of chromosomes called aneuploidy. This is a characteristic of cancer cells along with variation in differentiation of the cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 114
Correct
-
Phosphorylation of glucose once it enters the cell is catalysed by which enzyme?
Your Answer: Hexokinase
Explanation:Glucose 6-phosphate is produced by phosphorylation of glucose on the sixth carbon. This is catalysed by the enzyme hexokinase in most cells. One molecule of ATP is consumed in this reaction.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 115
Correct
-
The spinal cord receive its blood supply from the following arteries except:
Your Answer: Lateral spinal artery
Explanation:The spinal cord (SC) is supplied by the single anterior spinal artery which supplies the anterior two thirds of the SC and paired posterior spinal arteries supplying the posterior one third. Anastomoses between the spinal arteries supply the lateral column. These arteries originate near the cervico-occipital junction and therefore have a smaller calibre and often discontinue. Thus, they require reinforcement by segmental/radicular arteries which are branches of the ascending cervical artery, deep cervical artery, intercostal arteries, lumbar arteries and lateral sacral arteries
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This question is part of the following fields:
- Medicine
- Neurology
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Question 116
Correct
-
Which part of the cerebellum is primarily responsible for equilibrium and eye movements?
Your Answer: Vestibulocerebellum
Explanation:The vestibulocerebellum develops at the same time as the vestibular apparatus in the inner ear. Its regulates balance between agonist and antagonist muscle contractions of the spine, hips, and shoulders during rapid movements.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 117
Correct
-
The process whereby DNA fragments are separated by size and charge is called:
Your Answer: Gel electrophoresis
Explanation:Fragments of DNA of varying length can be separated on the basis of their charge and their size by a process called gel electrophoresis. Because DNA contains negatively charged phosphate groups, it will migrate in an electric field toward the positive electrode. Shorter chains migrate more rapidly through the pores of the gel, and thus separation depends on length. DNA bands in the gel can be visualized by various techniques including staining with dyes and autoradiography.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 118
Correct
-
Where does the anterior pituitary receive most of its blood supply?
Your Answer: Portal hypophysial vessels
Explanation:The anterior pituitary receives its arterial supply from the superior hypophyseal artery, which is a branch of the internal carotid that forms a capillary around the hypothalamus; thus forming the hypothalamo-hypophysial portal system.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 119
Correct
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Question 120
Incorrect
-
A 23 year old male presents with a history of lower back pain for the last one year. Presence of which of the following features most likely points towards ankylosing spondylitis?
Your Answer: Presence of HLA-B27 antigen on tissue typing
Correct Answer: Bilateral erosion of sacroiliac joints on X-ray
Explanation:Bilateral erosions of the sacroiliac joints on pelvic radiographs of patients with ankylosing spondylitis are an important feature of the modified New York classification criteria. Although HLA-B27 is commonly associated with AS, it can also be found in normal individuals. Back stiffness is worse in the morning and gets better as the day progresses. Tenderness and limited lumbar motion can be associated with other spine problems as well and is not characteristic of rheumatoid arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 121
Correct
-
Which of the following vitamin deficiencies is associated with xerophthalmia?
Your Answer: Vitamin A
Explanation:Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea. The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness as a result of corneal damage.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 122
Correct
-
Conjugation of proteins to which polypeptide marks them for degradation?
Your 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 123
Correct
-
Which inhibitor of gastric enzyme secretion is released by the presence of fat in the jejunum?
Your Answer: Peptide yy
Explanation:Peptide yy is secreted from the jejunum due to the presence of fat. It inhibits gastric acid secretion and motility.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 124
Incorrect
-
Which of the following best describe N. Meningitides?
Your Answer: Gram positive bacilli
Correct Answer: Gram negative cocci
Explanation:Neisseria meningitidis, often referred to as meningococcus, is a gram negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcaemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically, diplococcus because of its tendency to form pairs. About 10% of adults are carriers of the bacteria in their nasopharynx.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 125
Correct
-
A 60 year old male presents with one month history of generalized headache, fever and malaise. He also complains of scalp sensitivity while combing his hair. In order to confirm the diagnosis, which of the following would be the definite test?
Your Answer: Temporal artery biopsy
Explanation:Temporal arteritis is a chronic large- and medium-sized vessel vasculitis that typically involves the temporal arteries. Classical symptoms include temporal headaches, jaw claudication, amaurosis fugax. Physical exam shows scalp tenderness, palpation of the temporal area may demonstrate an absent pulse, knot-like swelling, and vision loss. Lab results reveal an increased erythematous sedimentation rate and C-reactive protein. Temporal artery biopsy confirms the diagnosis. Management approach: high-dose systemic corticosteroids should be promptly administered even before the diagnosis is established. Temporal artery biopsy confirms the diagnosis. Inability to manage this or administer glucocorticoids might lead to development of blindness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 126
Correct
-
A 30-year-old male is brought to the emergency department following his collapse in a night club. His friends who accompanied him admit that, of recent, he has been using increasing amounts of cocaine. Which among the following is commonly associated with cocaine overdose?
Your Answer: Metabolic acidosis
Explanation:Metabolic acidosis is associated with cocaine overdose. In overdose, cocaine leads to agitation, tachycardia, hypertension, sweating, hallucinations, and finally convulsions. Metabolic acidosis, hyperthermia, rhabdomyolysis, and ventricular arrhythmias also occur.Chronic use may be associated with premature coronary artery disease, dilated cardiomyopathy, and increased risk of cerebral haemorrhage.There are 3 stages for acute cocaine toxicity:Stage I: CNS symptoms of headache, vertigo, pseudo hallucinations, hyperthermia, hypertension. Stage II: increased deep tendon reflexes, tachypnoea, irregular breathing, hypertension.Stage III: Areflexia, coma, fixed and dilated pupils, hypotension, ventricular fibrillation, apnoea, and respiratory failure.Treatment:- Airway, breathing, and circulation to be secured. The patient’s fever should be managed, and one should rule out hypoglycaemia as a cause of the neuropsychiatric symptoms. – Cardiovascular toxicity and agitation are best-treated first-line with benzodiazepines to decrease CNS sympathetic outflow.- The mixed beta/alpha blocker labetalol is safe and effective for treating concomitant cocaine-induced hypertension and tachycardia.- Non-dihydropyridine calcium channels blockers such as diltiazem and verapamil have been shown to reduce hypertension reliably, but not tachycardia. – Dihydropyridine agents such as nifedipine should be avoided, as reflex tachycardia may occur. – The alpha-blocker phentolamine has been recommended but only treats alpha-mediated hypertension and not tachycardia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 127
Correct
-
Portal vein receives its blood from all the following except:
Your Answer: Kidney
Explanation:The portal vein receives blood from the intestines via the superior and inferior mesenteric veins, from stomach via the gastric veins and from the spleen and pancreas via splenic vein. The kidney is supplied by the renal artery and drains into the renal vein into the inferior venacava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 128
Incorrect
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A 68 year old male, previously diagnosed with osteoarthritis presents to your clinic with acute on chronic pain in his big toe. Past history is significant for hypertension for which he takes Bendroflumethiazide 5mg daily. Examination reveals an erythematous, red hot metatarsophalangeal joint that has a knobbly appearance. X-ray shows punched out bony cysts. Which of the following would be the most appropriate long term management for this patient?
Your Answer: Start ibuprofen
Correct Answer: Stop Bendroflumethiazide and substitute a calcium antagonist
Explanation:The most likely diagnosis is chronic tophaceous gout, which is classically associated with chronic renal impairment or long term diuretic therapy. There is tophus formation due to urate crystal deposition in and around the joint. These tophi can also form in the bones and soft tissues. Renal manifestations with uric acid include nephrolithiasis and uric acid nephropathy. Whenever there is an acute on chronic attack of gout, the inciting cause must be established and in case of diuretic use, they should be immediately replaced with another medication. Allopurinol is never started during an acute episode. it is first allowed to settle before administration of allopurinol. Although dietary restriction must be observed in people with a propensity of gout, this scenario clearly presents diuretics as the cause.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 129
Correct
-
According to Starling's law of the heart:
Your Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law 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 increased 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 the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 130
Correct
-
The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 131
Incorrect
-
Cholesterol is synthesized in all of these organs EXCEPT?
Your Answer: Adrenal cortex
Correct Answer: Stomach
Explanation:The liver primarily synthesizes about 20-25% of the total daily cholesterol. Cholesterol is also synthesized to smaller extents in the adrenal glands, reproductive organs (as cholesterol is the precursor of sex hormones), skin and is also produced in the intestines.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 132
Correct
-
Which of the following prevents auto-digestion of the stomach by gastric secretions:
Your Answer: Trefoil peptides and mucus- bicarbonate layer.
Explanation:Pepsinogen is the inactive form of pepsin, a protein digesting enzyme. Bombesin is a peptide which stimulates gastrin secreting cells in the stomach increasing production of gastric acid. Ecl or enterochromaffin cells are neuroendocrine cells that aid in the production of gastric acid via the release of histamine. Oxyntic cells are also known as parietal cells and are the main cells secreting gastric hydrochloric acid (HCl). Gastric acid and pepsin are harmful agents for the gastric mucosa and can result in autodigestion. It is therefore protected by several agents including bicarbonate which neutralizes the acidity of gastric acid while Trefoil peptides are a component of gastric mucosa that form a gel like layer in the gastric epithelium protecting it from harmful agents.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 133
Correct
-
The process by which DNA fragments are separated by gel and transferred onto a membrane sheet is called:
Your 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 134
Correct
-
Tunica intima is made up of?
Your Answer: Endothelial cells
Explanation:Tunica intima is a single cell thick lining of endothelial cells that lines the inside of the blood vessels. It is the inner most layer of the blood vessel.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 135
Incorrect
-
The pressure in the sinusoids is normally:
Your Answer: The same as portal venous pressure
Correct Answer: Lower than portal venous pressure
Explanation:The direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids. Thus, he pressure of sinusoids should be lower than the pressure of he portal vein.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 136
Correct
-
Renin is secreted by which of the following cells?
Your Answer: Juxtaglomerular cells
Explanation:The juxtaglomerular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles, and some in the efferent arterioles, that deliver blood to the glomerulus.
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This question is part of the following fields:
- Medicine
- Renal
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Question 137
Incorrect
-
Which of the following is correctly paired?
Your Answer: I cells : IgF – i
Correct Answer: F cells : pancreatic polypeptide
Explanation:Pancreatic polypeptide is secreted by F-cells, which represent the smallest proportion of islet cells in the pancreas. These cells establish the embryological origin of the pancreas. Pancreatic polypeptide regulates endocrine and exocrine activities by the pancreas.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 138
Incorrect
-
After exercise, O2 debt repay may take up to:
Your Answer: 12 hrs
Correct Answer: 90 min
Explanation:Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 139
Correct
-
The pathogen in variant Creutzfeldt Jacobs disease is an example of a:
Your Answer: Prion
Explanation:Types of Creutzfeldt Jacobs Disease (CJD) include:1. variant – This is thought to be caused by the consumption of food contaminated with prions, which also cause BSE.2. sporadic – This accounts for 85% of cases of CJD. 3. familial – This accounts for the majority of the other 15% cases of CJD.4. iatrogenic – This form of CJD arises from contamination with tissue from an infected person, usually as the result of a medical procedure.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 140
Correct
-
The Wiebel-Palade body found in the endothelial cells is responsible for the production and release of which factor?
Your Answer: Von Willebrand factor
Explanation:Weibel-Palade bodies are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in haemostasis and inflammation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 141
Correct
-
What is the most appropriate management of a DVT during pregnancy?
Your 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 142
Correct
-
The pathway responsible for the discriminative aspect of pain, is called the:
Your Answer: Neospinothalamic tract
Explanation:The spinothalamic tract is an ascending or a sensory tract, responsible for transmission of pain and temperature. The neospinothalamic tract is responsible for fast pain or discriminative pain whereas the palaeospinothalamic tract is responsible for transmission of slow pain.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 143
Incorrect
-
Which statement is correct about the clinical state of methemoglobinemia?
Your Answer: Methaemoglobin, present in the circulation in small quantities, can resemble cyanosis.
Correct Answer: May arise due to a hereditary deficiency of NADH.
Explanation:Methaemoglobin is a form of haemoglobin that contains ferric [Fe3+] iron and has a decreased ability to bind oxygen. Spontaneously formed methaemoglobin is normally reduced by protective enzyme systems, e.g., NADH methaemoglobin reductase, hence a deficiency of NADH may result in increased levels of methaemoglobin
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This question is part of the following fields:
- Haematology
- Medicine
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Question 144
Correct
-
Which of the following hormones cause negative feedback on the CRH/ACTH axis?
Your Answer: Cortisol
Explanation:The hypothalamic–pituitary–adrenal axis, also known as HPA axis is a set of interactions that regulate the secretion of several hormones through negative feedback. Cortisol, for example, is produced by the adrenal cortex, binds to its receptors in the hypothalamus and adenohypophysis and inhibits secretion of corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). The drop in CRH secretion leads to a decrease in ACTH secretion, which in turn causes less cortisol to be secreted.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 145
Correct
-
A 50-year-old man is admitted with nausea and excessive drowsiness after taking an antihistamine tablet with grapefruit juice. Which of the following liver enzyme systems is affected by grapefruit juice causing the given side effect?
Your Answer: Cytochrome p450 3A4
Explanation:The cytochrome p450 3A4 enzyme system in the liver is affected by grapefruit juice. Patients taking antihistamines should be advised to avoid drinking grapefruit juice. This is because constituents of grapefruit juice such as naringin and bergamottin inhibit CYP3A4 in the liver, particularly at high doses, leading to decreased drug elimination via hepatic metabolism and can increase potential drug toxicities. Inhibition of this enzyme system leads to reduced metabolism of antihistamines leading to an increased incidence of side effects like excessive drowsiness and nausea as in this patient.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 146
Incorrect
-
Majority of gastrinomas are found in the:
Your Answer: Stomach
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 147
Correct
-
Which are the main hormones secreted by the posterior pituitary gland.
Your Answer: Oxytocin and vasopressin
Explanation:The posterior pituitary gland secretes oxytocin and vasopressin (antidiuretic hormone). These hormones are stored in Herring bodies before being secreted into the bloodstream.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 148
Incorrect
-
In the clotting mechanism, activation of factor IX can occur through the direct actions of:
Your Answer: Factor XIa & XIIa
Correct Answer: Factor VIIa & XIa
Explanation:Factor IX is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, in the presence of Ca2+, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa. Factor IX is inhibited by antithrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 149
Correct
-
What happens first during depolarisation of the membrane potential?
Your Answer: Gated Na channels open allowing the influx of Na
Explanation:Generation of an action potential in response to a stimulus is a result of a previously maintained resting membrane potential (RMP). Generation of resting membrane potential is mediated mainly by potassium ions. Several membrane proteins maintain RMP by transport of ions in and out of cell. Na+/K+ ATPase pump maintains a concentration gradient of Na+ and K+ ions. Na+ concentration in extracellular fluid is higher compared to intracellular fluid and K+ ion concentration is higher intracellularly. Generation of an action potential facilitates opening of Na+ ion channels which allow for Na+ to diffuse inside the cell according to the concentration gradient.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 150
Correct
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Question 151
Incorrect
-
Which cells produce the immunoglobulin proteins involved in mediating humoral immunity?
Your Answer: Memory B cell
Correct Answer: Differentiated forms of B lymphocytes known as plasma cells
Explanation:After the B cells have been activated by a certain antigens, they transform into plasma cells. These plasma cells are responsible for the generation of antibodies (or immunoglobulins Ig) which are also known as regulators of humoral immunity. There are fives classes of Ig: IgA, IgG, IgM, IgE and IgD
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This question is part of the following fields:
- Immunology
- Medicine
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Question 152
Correct
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Question 153
Incorrect
-
Around 30 patients have been admitted to the hospital following a suspected chemical attack in the city. The patients are extremely unwell, with symptoms of excessive salivation, lacrimation, diarrhoea, and emesis. Sarin gas was suspected as the most likely agent used in the attack. What is the mechanism of action of this chemical agent?
Your Answer: Anti-cholinergic
Correct Answer: Inhibition of acetylcholinesterase
Explanation:Sarin acts by inhibiting acetylcholinesterase.Sarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesteraseSarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesterase. This results in high levels of acetylcholine (ACh).The effects of excessive ACh can be remembered by the mnemonic DUMBELLS:DiarrhoeaUrinationMiosis/muscle weaknessBronchorrhea/BradycardiaEmesisLacrimationSalivation/sweatingOrganophosphate insecticide poisoning:One of the effects of organophosphate poisoning is inhibition of acetylcholinesteraseFeatures can be predicted by the accumulation of acetylcholine (mnemonic = SLUD)SalivationLacrimationUrinationDefecation/diarrhoeacardiovascular: hypotension, bradycardiamiosis, muscle fasciculation.Organophosphate poisoning is treated with the anti-muscarinic atropine.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 154
Incorrect
-
The lower oesophageal sphincter is under neural control. Which of the following causes contraction of the intrinsic sphincter?
Your Answer: None of the above
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
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Question 155
Correct
-
Question 156
Correct
-
The process where by DNA fragments are separated by size and charge is called:
Your Answer: Gel electrophoresis
Explanation:Fragments of DNA of varying length can be separated on the basis of their charge and their size by a process called gel electrophoresis. Because DNA contains negatively charged phosphate groups, it will migrate in an electric field toward the positive electrode. Shorter chains migrate more rapidly through the pores of the gel, and thus separation depends on length. DNA bands in the gel can be visualized by various techniques including staining with dyes and autoradiography.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 157
Correct
-
The right border of the heart corresponds to which line on the surface of the chest?
Your Answer: Line drawn from the 3rd right costal cartilage to the 6th right costal cartilage
Explanation:The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 158
Correct
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The apical enzyme responsible for the oxidation and reaction of iodide with thyroglobulin is:
Your Answer: Thyroid peroxidise
Explanation:Thyroid peroxidase is an enzyme that is secreted into the thyroid colloid. It works by oxidizing iodide ions into iodine which are incorporated into thyroglobulin, in order to produce T3 and T4.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 159
Correct
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What effect does osmotic diuresis have on net Na+ excretion?
Your Answer: Markedly increased Na+ excretion
Explanation:Osmotic diuresis is the increase of urination rate caused by the presence of certain substances in the small tubes of the kidneys. The excretion occurs when substances such as glucose enter the kidney tubules and cannot be reabsorbed (due to a pathological state or the normal nature of the substance). The substances cause an increase in the osmotic pressure within the tubule, causing retention of water within the lumen, and thus reduces the reabsorption of water, increasing urine output (i.e. diuresis). Sodium, chloride, potassium are markedly excreted in osmotic diuresis.
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This question is part of the following fields:
- Medicine
- Renal
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Question 160
Correct
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Regarding the innervation of the cerebral blood vessels, postganglionic sympathetic neurons have their cell bodies in the:
Your 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 161
Incorrect
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Which of the following statements is true regarding pulsus alternans?
Your Answer: It is found in patients with a small pericardial effusion
Correct Answer: It is found in association with a third heart sound
Explanation:Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis. A pathological third heart sound is usually associated.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 162
Correct
-
Which one of the following features is least recognised in long-term lithium use?
Your Answer: Alopecia
Explanation:All the above side-effects, with the exception of alopecia, may be seen in patients taking lithium.Common lithium side effects may include:- dizziness, drowsiness;- tremors in your hands;- trouble walking;- dry mouth, increased thirst or urination;- nausea, vomiting, loss of appetite, stomach pain;- cold feeling or discoloration in your fingers or toes;- rash; or.- blurred vision.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 163
Incorrect
-
The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Antrum
Correct Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 164
Correct
-
The following play a role in regulation of intestinal iron absorption except:
Your Answer: Urinary iron excretion rate
Explanation:The human body’s rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, dietary intake, the extent to which the bone marrow is producing new red blood cells, the concentration of haemoglobin in the blood, and the oxygen content of the blood. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 165
Correct
-
Regarding cardiac output, an increased ejection fraction results from increases in which of the following?
Your Answer: Strength of contraction without increase in muscle fiber length
Explanation:When the strength of contraction increases without an increase in fiber length, the EF increases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 166
Incorrect
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Question 167
Incorrect
-
Stem cell characteristics include the following except
Your Answer: Differentiation and proliferation into progenitor cells committed to one cell line
Correct Answer: Differentiation and proliferation into progenitor cells committed to multiple cell lines
Explanation:The classical definition of a stem cell requires that it possess two properties:Self-renewal: the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.Potency: the capacity to differentiate into specialized cell types. In the strictest sense, this requires stem cells to be either totipotent or pluripotent to be able to give rise to any mature cell type
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This question is part of the following fields:
- Haematology
- Medicine
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Question 168
Incorrect
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Which ion channel is a dimer?
Your Answer: Na+ channel
Correct Answer: Cl- channel
Explanation:A dimer is a chemical structure formed from two similar sub-units. Chloride channels or exchangers are composed of two similar subunits—a dimer—each subunit containing one pore.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 169
Correct
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Question 170
Correct
-
Which of the following components regulate cardiac output?
Your 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
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Question 171
Correct
-
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: 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
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Question 172
Correct
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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: 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
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Question 173
Correct
-
In a patient with prostate cancer, what is the mechanism by which goserelin acts?
Your Answer: GnRH agonist
Explanation:Androgen deprivation therapy (ADT) for prostate cancer:Goserelin (Zoladex) is a synthetic gonadotropin-releasing hormone (GnRH) analogue; chronic stimulation of goserelin results in suppression of LH, FSH serum levels thereby preventing a rise in testosterone.Dosage form: 3.6 mg/10.8mg implants.Adverse effects include flushing, sweating, diarrhoea, erectile dysfunction, less commonly, rash, depression, hypersensitivity, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 174
Correct
-
Which of the following is NOT a cause of onycholysis?
Your Answer: Mycoplasma pneumonia
Explanation:Onycholysis is the separation of the distal edge of the nail from the vascular nailbed causing whiteness of the free edge. Causes include:- Idiopathic- Trauma, excessive manicuring- Infection: especially fungal- Skin disease: psoriasis, dermatitis- Impaired peripheral circulation e.g. Raynaud’s- Systemic disease: hyper/hypothyroidism, reactive arthritis, porphyria cutanea tarda- Sometimes a reaction to detergents (e.g. washing dishes with bare hands, using detergent-based shampoos or soaps).- Patients with hepatocellular dysfunction may develop hair-thinning or hair loss and nail changes such as clubbing, leukonychia (whitening), or onycholysis.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 175
Correct
-
Restriction fragment length polymorphisms/ Gene Knockout Mouse Models. All true except:
Your Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:Yeast chromosomes cannot be used as a vector. All the rest are true. Vectors can be bacteria, viruses and plasmids. DNA ligase binds the DNA fragment to the host DNA after insertion. Fluorescence can be used to visualize them.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 176
Correct
-
Which of the following is correct regarding lead poisoning?
Your Answer: Causes a peripheral neuropathy due to demyelination
Explanation:Lead can be absorbed through the skin and by inhalation. It is associated with iron deficiency and a microcytic anaemia. The most common gastrointestinal symptoms are abdominal colic and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 177
Correct
-
Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?
Your Answer: Displaced apex beat
Explanation:Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 178
Incorrect
-
The actions of thrombin result directly in the release of:
Your Answer: Fibrin dimers
Correct Answer: Fibrin monomers
Explanation:Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 179
Correct
-
G cells release which of the following substances
Your Answer: Gastrin
Explanation:The G cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 180
Correct
-
The posterior aspect of the interventricular septum is supplied by:
Your Answer: A branch of the right coronary artery
Explanation:The posterior aspect of the heart is supplied by the posterior interventricular artery which is a branch of the right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 181
Correct
-
The positive inotropic effect of digoxin is due to?
Your Answer: Inhibition of the sodium potassium ATPase in the myocardium
Explanation:Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 182
Correct
-
Which one of the following is not part of the WHO diagnostic criteria for the metabolic syndrome?
Your Answer: High LDL
Explanation:The World Health Organization 1999 criteria require the presence of any one of diabetes mellitus, impaired glucose tolerance, impaired fasting glucose or insulin resistance, AND two of the following:
- Blood pressure: ≥ 140/90 mmHg
- Dyslipidaemia: triglycerides (TG): ≥ 1.695 mmol/L and high-density lipoprotein cholesterol (HDL-C) ≤ 0.9 mmol/L (male), ≤ 1.0 mmol/L (female)
- Central obesity: waist: hip ratio > 0.90 (male); > 0.85 (female), or body mass index > 30 kg/m2
- Microalbuminuria: urinary albumin excretion ratio ≥ 20 µg/min or albumin: creatinine ratio ≥ 30 mg/g
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 183
Correct
-
In the presence of oxygen , lactate that was produced under anaerobic conditions is converted to:
Your 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 184
Incorrect
-
Iron absorption occurs primarily in which part of the GIT?
Your Answer: Terminal ileum
Correct Answer: Duodenum
Explanation:Like most mineral nutrients, the majority of the iron absorbed from digested food or supplements is absorbed in the duodenum by enterocytes of the duodenal lining.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 185
Correct
-
A patient who has recently been diagnosed with SLE undergoes serum testing. A rise in which of the following antibodies would indicate severe systemic involvement?
Your Answer: Anti double-stranded DNA antibodies
Explanation:Anti ds-DNA antibodies are very specific for SLE and their presence most often indicates systemic spread of the disease. These antibodies are present in about 30 percent of the total cases of SLE.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 186
Incorrect
-
Which neuron secretes glutamate as its neurotransmitter?
Your Answer: Stellate
Correct Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 187
Correct
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Question 188
Correct
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Question 189
Correct
-
The coronary sinus drains into the:
Your Answer: Right atrium
Explanation:The coronary sinus drains into the right atrium. Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 190
Incorrect
-
Which is true of the composition of bile in the human hepatic duct?
Your Answer: Water constitutes 97% of the solution
Correct Answer: Contains only actively secreted substances
Explanation:Hepatic bile is an isotonic fluid and its electrolyte composition resembles that of plasma. 97% of water is found in the gallbladder bile, not hepatic duct. Hepatic bile is alkaline. The ratio of bile acids: phosphatidylcholine: cholesterol is 20:1:3. Hepatic bile contai9ns only actively secreted substances.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 191
Correct
-
Which of these vitamins is not found in plants?
Your 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 192
Correct
-
What landmark divides the frontal and parietal lobes?
Your Answer: Central sulcus
Explanation:The central sulcus divides the frontal lobe from the parietal lobe. It contains the motor cells for the movement function of the body.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 193
Incorrect
-
Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?
Your Answer: Nos 2
Correct Answer: Nos 3
Explanation:There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 194
Correct
-
Consanguinity shows a strong association with which pattern of inheritance?
Your Answer: Autosomal recessive
Explanation:Consanguinity involves being from the same kinship as another person. It is a common feature of an autosomal recessive mode of inheritance
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This question is part of the following fields:
- Genetics
- Medicine
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Question 195
Correct
-
Medullary chemoreceptors
Your Answer: Monitor H+ concentration of the CSF
Explanation:Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 196
Correct
-
Which of the following does not lower ventricular rate in atrial fibrillation?
Your Answer: Adrenaline
Explanation:Adrenaline is a sympathetic neurotransmitter which increases the heart rate. During atrial fibrillation the atria is contracting at more than 200 beats/min. Acetylcholine is a parasympathetic neurotransmitter decreasing the heart rate. Digital also depresses the conduction at the AV conduction. Vagal discharge and occulocardiac reflux decrease the heart rate and convert the tachycardia into normal sinus rhythm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 197
Correct
-
A patient who has mild benign prostatic hyperplasia has been advised to take finasteride.The mechanism of action of this drug involves inhibition of the production of which of the following androgens?
Your Answer: Dihydrotestosterone
Explanation:Finasteride inhibits the formation of dihydrotestosterone.Finasteride is a 5α-reductase inhibitor and thus, inhibits the conversion of testosterone to dihydrotestosterone (DHT). DHT is much more active than testosterone and binds more avidly to cytoplasmic receptors. DHT stimulates prostate growth and may be responsible for benign prostatic hyperplasia in the elderly. Thus, finasteride can cause a reduction in prostatic volume and help in managing a patient with benign prostatic hyperplasia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 198
Incorrect
-
What does a deficiency of adenosine deaminase lead to?
Your Answer: Lesch-Nyhan syndrome
Correct Answer: SCID
Explanation:Severe combined immunodeficiency, SCID, also known as alymphocytosis, Glanzmann–Riniker syndrome, severe mixed immunodeficiency syndrome, and thymic alymphoplasia,[1] is a rare genetic disorder characterized by the disturbed development of functional T cells and B cells. Most cases of SCID are due to mutations in the gene encoding the common gamma chain (γc), a protein that is shared by the receptors for interleukins. The second most common form of SCID after X-SCID is caused by a defective enzyme, adenosine deaminase (ADA), necessary for the breakdown of purines.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 199
Correct
-
What is the mechanism of action of sildenafil citrate?
Your Answer: Inhibition of phosphodiesterase V
Explanation:Sildenafil citrate (Viagra) is the first oral drug to be widely approved for the treatment of erectile dysfunction. It is a potent and selective inhibitor of type-V phosphodiesterase, the primary form of the enzyme found in human penile erectile tissue, thereby preventing the breakdown of cyclic guanosine monophosphate (cGMP), the intracellular second messenger of nitric oxide.Uses:It is used for the treatment of erectile dysfunction, idiopathic pulmonary hypertension, premature ejaculation, high altitude illness, penile rehabilitation after radical prostatectomy, angina pectoris, and lower urinary tract symptoms.Adverse effects:Mild headache, flushing, dyspepsia, cyanopsia, back pain, and myalgias – due to a high concentration of PDE11 enzyme in skeletal muscle, which shows significant cross-reactivity with the use of tadalafil.It can also cause hypotension, dizziness, and rhinitis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 200
Correct
SESSION STATS - PERFORMANCE PER SPECIALTY
