-
Question 1
Correct
-
Regarding relationships between two variables, what does a negative correlation coefficient indicate:
Your Answer: The two variables are inversely related
Explanation:A negative correlation coefficient means that the two variables are inversely related e.g. socio-economic class and mortality.
-
This question is part of the following fields:
- Evidence Based Medicine
- Statistics
-
-
Question 2
Correct
-
A 4-year old boy is taken to the emergency room after a sudden onset of coughing and wheezing. Further investigation reveals that he was drawing quietly in his room, when suddenly, he became anxious and started coughing. The parents also noted that the eraser on top of the pencil was missing.
A plain radiographic chest imaging is conducted, and confirmed foreign body aspiration.
Which of the following areas in the tracheobronchial tree is the most probable location of the aspirated eraser?Your Answer: Right main bronchus
Explanation:In foreign body aspiration, the foreign body is more likely to enter the right main bronchus because it is shorter, wider and more vertical than the left main bronchus. In a patient who is standing or sitting, the foreign body tends to become lodged in the posterobasal segment of the inferior lobe of the right lung.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 3
Correct
-
Your consultant requests that you do a lumbar puncture on a patient who is suspected of having meningitis. This patient, a 15-year-old female, presented to the emergency department with a fever, headache, and neck stiffness. Where should you aspirate a sample of CSF?
Your Answer: Subarachnoid space
Explanation:A lumbar puncture, also known as a spinal tap, is a procedure that involves inserting a needle into the lower back’s lumbar region.
A needle is inserted into the space between the arachnoid mater and the pia mater, also known as the subarachnoid space, to remove a sample of cerebrospinal fluid.
-
This question is part of the following fields:
- Anatomy
- Head And Neck
-
-
Question 4
Correct
-
Which of the following statements is true about percutaneous needle aspiration?
Your Answer: The needle should be inserted just above the upper border of the chosen rib
Explanation:Pleural aspiration describes a procedure whereby pleural fluid or air may be aspirated via a system inserted temporarily into the pleural space. This may be for diagnostic purposes (usually removing 20–50 ml fluid) or therapeutic to relieve symptoms. In the literature it is varyingly called thoracocentesis, thoracentesis or pleural aspiration.
In determining the correct patient position and site of insertion, it is important for the operator to be aware of the normal anatomy of the thorax and the pathology of the patient. Patient position is dependent on the operator preference and the site of the pathology. In the case of a posterior lying locule, this may be specific to the image-guided spot where fluid is most likely to be obtained. In most circumstances, however, the site of insertion of the needle is either in the triangle of safety or the second intercostal space in the midclavicular line. The patient may therefore either sit upright leaning forward with arms elevated but resting on a table or bed, thereby exposing the axilla, or lying on a bed in a position. The needle is inserted in the space just above the chosen rib to avoid damaging the neurovascular bundle. It is common practice to insert the needle more posteriorly for a pleural aspiration, but it should be noted that the neurovascular bundle may not be covered by the lower flange of the rib in this position and a more lateral or anterior site of insertion is considered safer.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 5
Correct
-
Which of the following is the most abundant peripheral blood leucocyte:
Your Answer: Neutrophils
Explanation:Neutrophils are the most abundant peripheral blood leucocyte, comprising about 50 – 70% of circulating white cells. Neutrophils have a characteristic dense nucleus consisting of between two and five lobes, and a pale cytoplasm with an irregular outline containing many fine pink-blue or grey-blue granules. The granules are divided into primary, which appear at the promyelocyte stage, and secondary, which appear at the myelocyte stage and predominate in the mature nucleus. Both types of granule are lysosomal in origin; the primary contains myeloperoxidase and other acid hydrolases; the secondary contains lactoferrin, lysozyme and other enzymes. The lifespan of neutrophils in the blood is only 6 – 10 hours. In response to tissue damage, cytokines and complement proteins, neutrophils migrate from the bloodstream to the site of insult within minutes, where they destroy pathogens by phagocytosis.
-
This question is part of the following fields:
- Immune Responses
- Pathology
-
-
Question 6
Correct
-
Hartmann's solution contains how much sodium:
Your Answer: 131 mmol/L
Explanation:Hartmann’s solution (compound sodium lactate) contains: Na+131 mmol/L, K+5 mmol/L, HCO3-29 mmol/L (as lactate), Cl-111 mmol/L, Ca2+2 mmol/L. It can be used instead of isotonic sodium chloride solution during or after surgery, or in the initial management of the injured or wounded; it may reduce the risk of hyperchloraemic acidosis.
-
This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
-
-
Question 7
Correct
-
At which opioid receptors do opioid analgesics act primarily?
Your Answer: Mu
Explanation:Opioid receptors are widely distributed throughout the central nervous system. Opioid analgesics mimic endogenous opioid peptides by causing prolonged activation of these receptors, mainly the mu(μ)-receptors which are the most highly concentrated in brain areas involved in nociception.
-
This question is part of the following fields:
- Central Nervous System
- Pharmacology
-
-
Question 8
Correct
-
The patient is a 78-year-old woman who has recently developed left-sided hemiplegia. A CT head scan is performed, and the diagnosis of an ischaemic stroke is confirmed. Her blood pressure is currently very high, with the most recent measurement being 196/124 mmHg, according to the nurse in charge. While you wait for the stroke team to review her, she asks you to prescribe something to help lower the patient's blood pressure.
Which of the following is the best drug treatment for this patient's BP reduction?Your Answer: Labetalol
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.
In the setting of a stroke syndrome (i.e., in the presence of focal neurological deficits), hypertensive emergencies usually necessitate a slower and more controlled blood pressure reduction than in other situations. Rapid reduction of MAP in the presence of an ischaemic stroke can compromise blood flow, leading to further ischaemia and worsening of the neurological deficit. In this situation, intravenous labetalol is the drug of choice for lowering blood pressure.
Significantly elevated blood pressure (>185/110 mmHg) is a contraindication to thrombolysis, but there is some evidence for controlling blood pressure before thrombolysis in exceptional circumstances, when it is only slightly above this threshold.
-
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
-
-
Question 9
Correct
-
A 29-year-old female with chronic anaemia secondary to sickle cell disease is being transfused. A few minutes after starting the blood transfusion, she develops widespread itching with urticarial rash, wheezing, nausea and chest pain. Her BP reduces to 60/40 mmHg.
What is the most appropriate treatment?Your Answer: Stop the transfusion and administer adrenaline
Explanation:Anaphylaxis transfusion reaction occurs when an individual has previously been sensitized to an allergen present in the blood and, on re-exposure, releases IgE or IgG antibodies. Patients with anaphylaxis usually develop laryngospasm, bronchospasm, abdominal pain, nausea, vomiting, hypotension, shock, and loss of consciousness. The transfusion should be stopped immediately and the patient should be treated with adrenaline, oxygen, corticosteroids, and antihistamines.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 10
Correct
-
A patient presents with a rash for a dermatological examination. A flat circumscribed area of discoloured skin measuring 0.7 cm in diameter is seen on examination.
What is the best description of this rash that you have found on examination?
Your Answer: Macule
Explanation:A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
A vesicle is a visible collection of clear fluid measuring less than 0.5 cm in diameter.
A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter.
-
This question is part of the following fields:
- General Pathology
- Pathology
-
-
Question 11
Correct
-
Which of the following serology results is consistent with chronic hepatitis B infection:
Your Answer: HBsAg positive and anti-HBc IgG positive
Explanation:Disease state vs Serology
Acute hepatitis: BHBsAg, HBeAg, anti-HBc IgM
Chronic hepatitis B (low infectivity): HBsAg (>6/12), anti-HBe, anti-HBc IgG
Chronic hepatitis B (high infectivity): HBsAg (>6/12), HBeAg, anti-HBc IgG
Cleared infection: Anti-HBs, anti-HBe, anti-HBc IgG
Vaccinated: Anti-HBs -
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 12
Correct
-
A patient complains of stomach ache. You see a midline scar in the epigastric area when you examine the abdomen. Upon further interrogation, the patient reveals that she had a subtotal gastrectomy for recurring stomach ulcers several years ago. The stomach mucosa secretes a variety of vital compounds, and her ability to secrete some of these molecules has been harmed as a result of his surgery.
The stomach G-cells are responsible for which of the following?Your Answer: Secretion of gastrin
Explanation:G-cells are a type of cell found in the stomach’s pyloric antrum, duodenum, and pancreas. The secretion of the peptide hormone gastrin is their major function.
The table below summarizes the many cell types found in the stomach, as well as the substances secreted by each cell type and the function of the secretion:
Cell type/ Substance secreted/ Function of secretion
Parietal cells/ Hydrochloric acid/ Kills microbes and activates pepsinogen
Parietal cells/ Intrinsic factor/Binds to vitamin B12 and facilitates its absorption
Chief cells/ Pepsinogen/ Protein digestion
Chief cells/ Gastric lipase/ Fat digestion
G-cells/ Gastrin/ Stimulates gastric acid secretion
Enterochromaffin-like cells (ECL cells) /Histamine/ Stimulates gastric acid secretion
Mucous-neck cells/ Mucous and bicarbonate/ Protects stomach epithelium from acid
D-cells/ Somatostatin/ Inhibits gastric acid secretion -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 13
Incorrect
-
A 17-year-old patient with a headache, fever, and a non-blanching rash is brought to the emergency room. Meningococcal infection is confirmed by a lumbar puncture. Neisseria meningitidis uses one of the following immune evasion mechanisms:
Your Answer: Produces exotoxin
Correct Answer: Secretes IgA protease
Explanation:Meningococci have 3 important virulence factors, as follows:
Polysaccharide capsule – Individuals with immunity against meningococcal infections have bactericidal antibodies against cell wall antigens and capsular polysaccharides; a deficiency of circulating anti meningococcal antibodies is associated with the disease.
Lipo-oligosaccharide endotoxin (LOS)
Immunoglobulin A1 (IgA1) -
This question is part of the following fields:
- Microbiology
- Principles
-
-
Question 14
Incorrect
-
Which of the following best describes the order in which blood passes through the nephron?
Your Answer: Afferent arteriole→Glomerular capillary→Peritubular capillary→Efferent arteriole→Vasa recta
Correct Answer: Afferent arteriole→Glomerular capillary→Efferent arteriole→Peritubular capillary→Vasa recta
Explanation:The nephron’s blood flow is as follows:
Afferent arteriole – Glomerular capillary – Efferent arteriole – Peritubular capillary – Vasa recta – Afferent arteriole – Glomerular capillary – Efferent arteriole – Peritubular capillary – Vasa rectaThe kidney is the only vascular network in the body with two capillary beds. With arterioles supplying and draining the glomerular capillaries, higher hydrostatic pressures at the glomerulus are maintained, allowing for better filtration. A second capillary network at the tubules enables for secretion and absorption in the tubules, as well as concentrating urine.
-
This question is part of the following fields:
- Physiology
- Renal Physiology
-
-
Question 15
Incorrect
-
Regarding the varicella zoster virus, which of the following statements is CORRECT:
Your Answer: The varicella zoster vaccine is part of routine childhood immunisation.
Correct Answer: Contracting chickenpox infection while pregnant is associated with a higher risk of developing varicella pneumonitis.
Explanation:Chickenpox infection in neonates, adults/adolescents and pregnant women is associated with more severe disease. Varicella zoster pneumonitis typically occurs in pregnant women or immunocompromised individuals and is associated with a high mortality. A live attenuated-virus vaccine is available and recommended for non-immune healthcare workers but is not part of the routine childhood immunisation schedule. Antiviral treatment is not typically recommended in childhood chickenpox but is indicated for shingles.
-
This question is part of the following fields:
- Microbiology
- Pathogens
-
-
Question 16
Correct
-
A 40-year-old woman presents with retrosternal central chest pain that she has been complaining about for the past two days. Upon deep inspiration and while lying flat, the pain worsens but relieved by sitting forwards. The pain radiates to both of her shoulders. The result of her ECG shows widespread concave ST-elevation and PR depression. A diagnosis of pericarditis is suspected.
Which of the following nerves is responsible for the pattern of her pain?Your Answer: Phrenic nerve
Explanation:Pericarditis is inflammation of the pericardial sac and is the most common pathologic process involving the pericardium. Frequently, pericardial inflammation can be accompanied by increased fluid accumulation within the pericardial sac forming a pericardial effusion, which may be serous, hemorrhagic or purulent depending on aetiology.
The classic presentation is with chest pain that is central, severe, pleuritic (worse on deep inspiration) and positional (improved by sitting up and leaning forward). The pain may also be radiating and may involve the ridges of the trapezius muscle if the phrenic nerve is inflamed as it traverses the pericardium.
-
This question is part of the following fields:
- Anatomy
- Thorax
-
-
Question 17
Correct
-
Regarding iron deficiency anaemia, which of the following statements is INCORRECT:
Your Answer: Dietary insufficiency is the most common cause of iron deficiency anaemia in adult men in the UK.
Explanation:Blood loss from the gastrointestinal (GI) tract is the most common cause of iron deficiency anaemia in adult men and postmenopausal women.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 18
Incorrect
-
Regarding thalassaemia, which of the following statements is CORRECT:
Your Answer: Beta-thalassaemias are usually caused by deletion of a beta globin gene.
Correct Answer: Screening for thalassaemia in pregnancy is offered to all pregnant women.
Explanation:Beta thalassemia is caused by mutations in one or both of the beta globin genes. Alpha thalassemia is caused by a deletion or mutation (less commonly) in one or more of the four alpha globin gene copies. β-thalassaemia is more common in the Mediterranean region while α-thalassaemia is more common in the Far East.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 19
Incorrect
-
After collapsing in his nursing home, a 70-year-old man is brought into the ER. He has diabetes mellitus and is on medication for it. An RBS of 2.0 mmol/L (3.9-5.5 mmol/L) is recorded in the ER.
Out of the following, which medication for diabetes mellitus is LEAST likely responsible for his hypoglycaemic episode?Your Answer: Actrapid
Correct Answer: Metformin
Explanation:Metformin is a biguanide used as the first-line to treat type 2 diabetes mellitus. It has a good reputation as it has an extremely low risk of causing hypoglycaemia compared to the other agents for diabetes. It does not affect the insulin secreted by the pancreas or increase insulin levels. Toxicity with metformin can, however, cause lactic acidosis with associated hypoglycaemia.
-
This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
-
-
Question 20
Correct
-
In patients requiring oxygen, who are at risk of hypercapnic respiratory failure, oxygen saturations should be maintained at:
Your Answer: 88 - 92%
Explanation:A lower target of 88 – 92% oxygen saturation is indicated for patients at risk of hypercapnic respiratory failure e.g. patients with COPD. Until blood gases can be measured, initial oxygen should be given using a controlled concentration of 28% or less, titrated towards the SpO2 of 88 – 92%. The aim is to provide the patient with enough oxygen to achieve an acceptable arterial oxygen tension without worsening carbon dioxide retention and respiratory acidosis.
-
This question is part of the following fields:
- Pharmacology
- Respiratory
-
-
Question 21
Correct
-
What is the direct mechanism of action of digoxin as a positive inotrope:
Your Answer: Inhibition of Na+/K+ ATPase pump
Explanation:Digoxin directly inhibits membrane Na+/K+ ATPase, which is responsible for Na+/K+ exchange across the myocyte cell membrane. This increases intracellular Na+ and produces a secondary increase in intracellular Ca2+ that increases the force of myocardial contraction. The increase in intracellular Ca2+ occurs because the decreased Na+ gradient across the membrane reduces the extrusion of Ca2+ by the Na+/Ca2+ exchanger that normally occurs during diastole. Digoxin and K+ ions compete for the receptor on the outside of the muscle cell membrane, and so the effects of digoxin may be dangerously increased in hypokalaemia.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 22
Correct
-
Which of the following statements is correct regarding the neuronal action potential?
Your Answer: Initial depolarisation occurs as a result of a Na + influx.
Explanation:The resting potential in most neurons has a value of approximately -70 mV.
The threshold potential is generally around -55 mV.
Initial depolarisation when there is Na+influx through ligand-gated Na+channels.
Action potential is an all or nothing response. The size of the action potential is constant and so, the intensity of the stimulus is coded by the frequency of firing of a neuron.
K+efflux is responsible for repolarisation. -
This question is part of the following fields:
- Basic Cellular
- Physiology
-
-
Question 23
Correct
-
A 23-year-old male presents to his family physician with the complaint of repeated episodes of abdominal pain and the passage of dark coloured urine every morning. He also reports increasing fatigue over the past several months. On examination, there are raised, painful red nodules over the skin of the back. Laboratory workup shows haemolytic anaemia, leukopenia and thrombocytopenia.
Which one of the following disorders is this patient most likely to have?Your Answer: Paroxysmal nocturnal haemoglobinuria
Explanation:Paroxysmal nocturnal haemoglobinuria is an acquired genetic disorder that causes a decrease in red blood cells due to a membrane defect that allows increased complement binding to RBCs, causing haemolysis. Patients complain of dark-coloured urine first in the morning due to haemoglobinuria secondary to lysis of red blood cells overnight.
Thrombosis occurs, which affects hepatic, abdominal, cerebral and subdermal veins. Thrombosis of hepatic veins can lead to Budd-Chiari syndrome, thrombosis of subdermal veins can lead to painful nodules on the skin, and thrombosis of cerebral vessels can lead to stroke. The presence of dark urine in the morning only and at no other time differentiates this condition from other conditions.
Multiple myeloma would present with bone pain, signs of radiculopathy if there were nerve root compression and a history of repeated infections.
Patients with Non-Hodgkin Lymphoma would complain of enlarged lymph nodes, fatigue, fever, weight loss and a history of repeated infections.
Acute lymphoblastic leukaemia presents more commonly in children than in adults. The patient would complain of bone pain, and on examination, there would be hepatosplenomegaly.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 24
Correct
-
A patient complains of stomach ache. You see a midline scar in the epigastric area when you examine the abdomen. Upon further interrogation, the patient reveals that she had a subtotal gastrectomy for recurring stomach ulcers several years ago. The stomach mucosa secretes a variety of vital compounds, and her ability to secrete some of these molecules has been harmed as a result of his surgery.
The stomach mucous neck cells secrete which of the following substances?
Your Answer: Bicarbonate
Explanation:Foveolar cells, also known as gastric mucous-neck cells, are cells that line the stomach mucosa and are found in the necks of the gastric pits. Mucus and bicarbonate are produced by these cells, which prevent the stomach from digesting itself. At pH 4, the mucous allows the acid to penetrate the lining, while below pH 4, the acid is unable to do so. Viscous fingering is the term for this procedure.
The table below summarizes the many cell types found in the stomach, as well as the substances secreted by each cell type and the function of the secretion:
Cell type/ Substance secreted/ Function of secretion
Parietal cells/ Hydrochloric acid/ Kills microbes and activates pepsinogen
Parietal cells/ Intrinsic factor/Binds to vitamin B12 and facilitates its absorption
Chief cells/ Pepsinogen/ Protein digestion
Chief cells/ Gastric lipase/ Fat digestion
G-cells/ Gastrin/ Stimulates gastric acid secretion
Enterochromaffin-like cells (ECL cells) /Histamine/ Stimulates gastric acid secretion
Mucous-neck cells/ Mucous and bicarbonate/ Protects stomach epithelium from acid
D-cells/ Somatostatin/ Inhibits gastric acid secretion -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 25
Incorrect
-
You suspect an anaphylactic reaction in a patient who is hypotensive, with trouble breathing after eating peanuts. Which of the following diagnostic tests will confirm this?
Your Answer: Specific IgE (RAST) test
Correct Answer: Mast cell tryptase
Explanation:The concentration of serum tryptase rises in anaphylaxis and anaphylactoid responses.
Because tryptase is a significant component of mast cell granules, mast cell degranulation causes elevated tryptase levels in the blood.
Although tryptase levels are not always high during anaphylaxis, it is considered a particular marker.
-
This question is part of the following fields:
- Pharmacology
- Respiratory
-
-
Question 26
Correct
-
Where:
Capillary hydrostatic pressure is (P c)Hydrostatic pressure in the interstices is (P I )
Plasma oncotic pressure is (Ï€ p)Interstitial oncotic pressure is (Ï€ i)
Which of the following formulas best represents fluid flow at the capillary bed?
Your Answer: Volume / min = (P c - P i ) - (π p - π i )
Explanation:Starling’s equation for fluid filtration describes fluid flow at the capillary bed.
Filtration forces (capillary hydrostatic pressure and interstitial oncotic pressure) stimulate fluid movement out of the capillary, while resorption forces promote fluid movement into the capillary (interstitial hydrostatic pressure and plasma oncotic pressure). Although the forces fluctuate along the length of the capillary bed, overall filtration is achieved.At the capillary bed, there is fluid movement.
The reflection coefficient (σ), the surface area accessible (S), and the hydraulic conductance of the wall (Lp) are frequently used to account for the endothelium’s semi-permeability, yielding:
Volume / min = LpS [(Pc- Pi) –  σ(Ï€p– Ï€i)]
Volume /min = (Pc-Pi) – (Ï€p–πi) describes the fluid circulation at the capillaries.
Where:
Pc= capillary hydrostatic pressure
Pi= interstitial hydrostatic pressure
Ï€p= plasma oncotic pressure
Ï€i= interstitial oncotic pressure -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
-
-
Question 27
Correct
-
A patient complains of stomach ache. You see a midline scar in the epigastric area when you examine the abdomen. Upon further interrogation, the patient reveals that she had a subtotal gastrectomy for recurring stomach ulcers several years ago. The stomach mucosa secretes a variety of vital compounds, and her ability to secrete some of these molecules has been harmed as a result of his surgery.
The gastric ECL cells secrete which of the following substances?
Your Answer: Histamine
Explanation:Enterochromaffin-like cells (ECL cells) are a type of neuroendocrine cell located beneath the epithelium in the stomach glands. They’re most typically located near the parietal cells of the stomach. The ECL cells’ primary role is to produce histamine, which stimulates the formation of stomach acid by the parietal cells.
The table below summarizes the many cell types found in the stomach, as well as the substances secreted by each cell type and the function of the secretion:
Cell type/ Substance secreted/ Function of secretion
Parietal cells/ Hydrochloric acid/ Kills microbes and activates pepsinogen
Parietal cells/ Intrinsic factor/Binds to vitamin B12 and facilitates its absorption
Chief cells/ Pepsinogen/ Protein digestion
Chief cells/ Gastric lipase/ Fat digestion
G-cells/ Gastrin/ Stimulates gastric acid secretion
Enterochromaffin-like cells (ECL cells) /Histamine/ Stimulates gastric acid secretion
Mucous-neck cells/ Mucous and bicarbonate/ Protects stomach epithelium from acid
D-cells/ Somatostatin/ Inhibits gastric acid secretion -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
-
-
Question 28
Correct
-
The last two segments of the nephrons are the distal convoluted tubule (DCT) and collecting duct (CD).
Which cell reabsorbs sodium more in the late DCT and CD?Your Answer: Principal cells
Explanation:The main Na+ reabsorbing cells in the late distal convoluted tubule and collecting duct are the principal cells. These make up the majority of the tubular cells.
The exchange is driven by the Na.K.ATPase pumps on the basolateral membrane.
-
This question is part of the following fields:
- Physiology
- Renal Physiology
-
-
Question 29
Incorrect
-
Which of the following is NOT a typical clinical feature of osteomalacia:
Your Answer: Waddling gait
Correct Answer: Hypercalcaemia
Explanation:Features of osteomalacia include:
Bone pain (particularly bone, pelvis, ribs)
Neuromuscular dysfunction (particularly in the gluteal muscles, leading to waddling gait
Pseudofractures on x-ray (looser zones)
Elevated alkaline phosphatase, hypocalcaemia and low phosphate due to secondary hyperparathyroidism -
This question is part of the following fields:
- Endocrine
- Physiology
-
-
Question 30
Correct
-
Fusidic acid is primarily indicated for infections caused by which of the following microorganisms:
Your Answer: Staphylococcal infections
Explanation:Fusidic acid is a narrow spectrum antibiotic used for staphylococcal infections, primarily topically for minor staphylococcal skin (impetigo) or eye infection. It is sometimes used orally for penicillin-resistant staphylococcal infection, including osteomyelitis or endocarditis, in combination with other antibacterials.
-
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 31
Correct
-
Regarding bile, which of the following statements is INCORRECT:
Your Answer: The sphincter of Oddi contracts to force bile from the gallbladder into the duodenum.
Explanation:Bile is secreted by hepatocytes. It is isotonic and resembles plasma ionically. This fraction of bile is called the bile acid-dependent fraction. As it passes along the bile duct, the bile is modified by epithelial cells lining the duct by the addition of water and bicarbonate ions; this fraction is called the bile acid-independent fraction. Overall, the liver can produce 500 – 1000 mL of bile per day. The bile is either discharged directly into the duodenum or stored in the gallbladder. The bile acid-independent fraction is made at the time it is required i.e. during digestion of chyme. The bile acid-dependent fraction is made when the bile salts are returned from the GI tract to the liver, and is then stored in the gallbladder until needed. The gallbladder not only stores bile but concentrates it by removing non-essential solutes and water, leaving bile acids and pigments, mainly by active transport of Na+into the intercellular spaces of the lining cells which, in turn, draws in water, HCO3-and Cl-from the bile and into the extracellular fluid. Within a few minutes of a meal, particularly when fatty foods have been consumed, the gallbladder contracts and releases bile into the bile duct. The sphincter of Oddi is relaxed, allowing the bile to pass into the duodenum through the ampulla of Vater.
-
This question is part of the following fields:
- Gastrointestinal
- Physiology
-
-
Question 32
Incorrect
-
Which of the following is NOT a function of antibodies:
Your Answer: Neutralise toxins
Correct Answer: Act as antigen receptors on T lymphocytes
Explanation:Antibodies:
Neutralise toxins and prevent attachment of pathogens
Target, opsonise or agglutinate (clump together) antigens for phagocytosis
Activate the complement cascade (leading to lysis or opsonisation of the pathogen)
Act as antigen receptors on B lymphocytes
Activate antibody-dependent cell-mediated cytotoxicity by natural killer (NK) cells or T cytotoxic cells
Provide mucosal immunity (IgA-mediated)
Stimulate degranulation of mast cells (IgE and IgG mediated)
Provide passive immunity to the newborn (through transplacental passage of IgG and secretion of IgA in breast milk) -
This question is part of the following fields:
- Immune Responses
- Pathology
-
-
Question 33
Correct
-
You assess a patient that has suffered a nerve injury that has paralysed her left latissimus dorsi muscle.
Latissimus dorsi receives its innervation from which of the following nerves? Select ONE answer only.Your Answer: Thoracodorsal nerve
Explanation:Latissimus dorsi originates from the lower part of the back, where it covers a wide area. It lies underneath the inferior fibres of trapezius superiorly, and trapezius is the most superficial back muscle.
Superficial muscles of the back showing latissimus dorsi (from Gray’s Anatomy)
Latissimus dorsi has a broad origin, arising from the spinous processes of T6-T12, the thoracolumbar fascia, the iliac crest and the inferior 3 or 4 ribs. The fibres converge into a tendon that inserts into the intertubercular groove of the humerus.
Latissimus dorsi is innervated by the thoracodorsal nerve.
Latissimus dorsi acts to extend, adduct and medially rotate the humerus. It, therefore, raises the body towards the arm during climbing. -
This question is part of the following fields:
- Anatomy
- Upper Limb
-
-
Question 34
Correct
-
Which of the following diseases is caused by a build-up of lymphoblasts in the bone marrow?
Your Answer: Acute lymphoblastic leukaemia
Explanation:Acute lymphoblastic leukaemia (ALL) is a clonal (malignant) bone marrow disorder in which early lymphoid precursors multiply and replace the marrow’s normal hematopoietic cells. ALL is most common between the ages of 3 and 7, with 75 percent of cases occurring before the age of 6.
-
This question is part of the following fields:
- Haematology
- Pathology
-
-
Question 35
Incorrect
-
Which of the following is typically used in diabetes mellitus as the cut-off to define hypoglycaemia?
Your Answer: < 4.0 mmol/L
Correct Answer:
Explanation:Hypoglycaemia is defined as plasma glucose of less than 4 mmol/L.
-
This question is part of the following fields:
- Endocrine
- Physiology
-
-
Question 36
Incorrect
-
Cardiac muscle and skeletal muscle are alike, but there are a few key variations.
Which of the following is NOT a characteristic of skeletal muscle but is a characteristic of cardiac muscle?ÂYour Answer: Multiple nuclei located peripherally
Correct Answer: The presence of intercalated discs
Explanation:Cardiac muscle is striated, and the sarcomere is the contractile unit, similar to skeletal muscle. Contracture is mediated by the interaction of calcium, troponins, and myofilaments, much as it occurs in skeletal muscle. Cardiac muscle, on the other hand, differs from skeletal muscle in a number of ways.
In contrast to skeletal muscle cells, cardiac myocytes have a nucleus in the middle of the cell and sometimes two nuclei. The cells are striated because the thick and thin filaments are arranged in an orderly fashion, although the arrangement is less well-organized than in skeletal muscle.
Intercalated discs, which work similarly to the Z band in skeletal muscle in defining where one cardiac muscle cell joins the next, are a very significant component of cardiac muscle.
Adherens junctions and desmosomes, which are specialized structures that hold the cardiac myocytes together, are formed by the transverse sections. The lateral sections produce gap junctions, which join the cytoplasm of two cells directly, allowing for rapid action potential conduction. These critical properties allow the heart to contract in a coordinated manner, allowing for more efficient blood pumping.
Cardiac myocytes have the ability to create their own action potentials, which is referred to as myogenic’. They can depolarize spontaneously to initiate a cardiac action potential. Pacemaker cells, as well as the sino-atrial (SA) and atrioventricular (AV) nodes, control this.
The Purkinje cells and the cells of the bundle of His are likewise capable of spontaneous depolarization. While the bundle of His is made up of specialized myocytes, it’s vital to remember that Purkinje cells are not myocytes and have distinct characteristics. They are larger than myocytes, with fewer filaments and more gap junctions than myocytes. They conduct action potentials more quickly, allowing the ventricles to contract synchronously.
Cardiac myocytes contract by excitation-contraction coupling, just like skeletal myocytes. Heart myocytes, on the other hand, utilise a calcium-induced calcium release mechanism that is unique to cardiac muscle (CICR). The influx of calcium ions (Ca2+) into the cell causes a ‘calcium spark,’ which causes more ions to be released into the cytoplasm.An influx of sodium ions induces an initial depolarisation, much as it does in skeletal muscle; however, in cardiac muscle, the inflow of Ca2+ sustains the depolarisation, allowing it to remain longer. Due to potassium ion (K+) inflow, CICR causes a plateau phase in which the cells remain depolarized for a short time before repolarizing. Skeletal muscle, on the other hand, repolarizes almost instantly.
-
This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
-
-
Question 37
Correct
-
Lidocaine's antiarrhythmic mode of action is as follows:
Your Answer: Blocks inactivated Na+ channels
Explanation:Lidocaine is a class 1B antidysrhythmic; combines with fast Na channels and thereby inhibits recovery after repolarization, resulting in decreasing myocardial excitability and conduction velocity. However, in ischaemic areas, where anoxia causes depolarisation and arrhythmogenic activity, many Na+ channels are inactivated and therefore susceptible to lidocaine.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 38
Correct
-
The following statements about cross-sectional studies are true EXCEPT?
Your Answer: They can be used to determine the relative risk of a condition
Explanation:The UK national census is an example of a cross-sectional study.
Cross-sectional studies can be used to assess the prevalence of a condition, and support or refute inferences of cause and effect.
Cross-sectional studies are observations of the frequency and characteristics of a disease in a given population at one particular point in time.
Cross-sectional studies do not differentiate between cause and effect and also do not establish the sequence of events.
Cross-sectional studies cannot be used to calculate the relative risk of a condition.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 39
Correct
-
An ambulance transports a 23-year-old woman who has taken a witnessed overdose of her mother's diazepam tablets. She has no significant medical history and does not take any medications on a regular basis.
In this case, what is the SINGLE MOST APPROPRIATE FIRST DRUG TREATMENT?Your Answer: Flumazenil IV 200 μg
Explanation:Flumazenil is a benzodiazepine antagonist that can be helpful in some overdose situations. It works quickly (in less than a minute), but the effects are fleeting, lasting less than an hour. The dose is 200 micrograms every 1-2 minutes with a maximum dose of 3 milligrams per hour.
Flumazenil should be avoided by patients who are addicted to benzodiazepines or who take tricyclic antidepressants because it can cause withdrawal symptoms. It can cause seizures or cardiac arrest in these situations.
-
This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
-
-
Question 40
Incorrect
-
You review a 46-year-old woman who has recently been prescribed antibiotics for a urinary tract infection. She suffers from COPD and is currently prescribed salbutamol and Seretide inhalers, and Phyllocontin continus. Since starting the antibiotics, she has been experiencing nausea, vomiting and abdominal pain.
Which of the following antibiotics is she MOST LIKELY to have been prescribed for her UTI? Select ONE answer only .Your Answer: Nitrofurantoin
Correct Answer: Ciprofloxacin
Explanation:Phyllocontin continus contains aminophylline (a mixture of theophylline and ethylenediamine), a bronchodilator used in the management of COPD and asthma.
This patient is exhibiting symptoms of theophylline toxicity, which may have been triggered by the prescription of the antibiotic. Quinolone antibiotics, such as ciprofloxacin and levofloxacin, and macrolide antibiotics, such as erythromycin, increase the plasma concentration of theophyllines and can lead to toxicity.
The drugs that commonly affect the half-life and the plasma concentration of theophylline are summarised in the table below:
Drugs increasing plasma concentration of theophylline
Drugs decreasing plasma concentration of theophylline
Calcium channel blockers, e.g. Verapamil
Cimetidine
Fluconazole
Macrolides, e.g. erythromycin
Quinolones, e.g. ciprofloxacin
Methotrexate
Barbiturates
Carbamazepine
Phenobarbitol
Phenytoin (and fosphenytoin)
Rifampicin
St. John’s wort -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
-
-
Question 41
Correct
-
A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle weakness and headaches. She is known to be hypertensive and takes amlodipine to control this. Her blood results today show that her potassium level is low at 3.0 mmol/L, and her sodium level is slightly elevated at 146 mmol/L.
Which of the following is the SINGLE most appropriate INITIAL investigation?Your Answer: Plasma renin and aldosterone levels
Explanation:Primary hyperaldosteronism occurs when there are excessive levels of aldosterone independent of the renin-angiotensin axis. Secondary hyperaldosteronism occurs due to high renin levels.
The causes of primary hyperaldosteronism include:
Adrenal adenoma (Conn’s syndrome) – the most common cause of hyperaldosteronism (,80% of all cases). These are usually unilateral and solitary and are more common in women.
Adrenal hyperplasia – this accounts for ,15% of all cases. Usually, bilateral adrenal hyperplasia (BAH) but can be unilateral rarely. More common in men than women.
Adrenal cancer – a rare diagnosis but essential not to miss
Familial aldosteronism – a rare group of inherited conditions affecting the adrenal glands
The causes of secondary hyperaldosteronism include:
Drugs – diuretics
Obstructive renal artery disease – renal artery stenosis and atheroma
Renal vasoconstriction – occurs in accelerated hypertension
Oedematous disorders – heart failure, cirrhosis and nephrotic syndrome
Patients are often asymptomatic. When clinical features are present, the classically described presentation of hyperaldosteronism is with:
Hypertension
Hypokalaemia
Metabolic alkalosis
Sodium levels can be normal or slightly raised
Other, less common, clinical features include:
Lethargy
Headaches
Muscle weakness (from persistent hypokalaemia)
Polyuria and polydipsia
Intermittent paraesthesia
Tetany and paralysis (rare)
Often the earliest sign of hyperaldosteronism is from aberrant urea and electrolytes showing hypokalaemia and mild hypernatraemia. If the patient is taking diuretics, and the diagnosis is suspected, these should be repeated after the patient has taken off diuretics.
If the diagnosis is suspected, plasma renin and aldosterone levels should be checked. Low renin and high aldosterone levels (with a raised aldosterone: renin ratio) is suggestive of primary aldosteronism.
If the renin: aldosterone ratio is high, then the effect of posture on renin, aldosterone and cortisol can be investigated to provide further information about the underlying cause of primary hyperaldosteronism. Levels should be measured lying at 9 am and standing at noon:
If aldosterone and cortisol levels fall on standing, this is suggestive of an ACTH dependent cause, e.g. adrenal adenoma (Conn’s syndrome)
If aldosterone levels rise and cortisol levels fall on standing, this is suggestive of an angiotensin-II dependent cause, e.g. BAH
Other investigations that can help to distinguish between an adrenal adenoma and adrenal hyperplasia include:
CT scan
MRI scan
Selective adrenal venous sampling -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
-
-
Question 42
Correct
-
All of the muscles of the tongue (other than the palatoglossus) are innervated by which of the following nerves:
Your Answer: Hypoglossal nerve
Explanation:All of the muscles of the tongue are innervated by the hypoglossal nerve, except for the palatoglossus, which is innervated by the vagus nerve.
-
This question is part of the following fields:
- Anatomy
- Head And Neck
-
-
Question 43
Incorrect
-
In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic disrupts cell membrane function.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer: Isoniazid
Correct Answer: Nystatin
Explanation:Nystatin binds ergosterol (unique to the fungi cell membrane) and forms membrane pores that allow K+ leakage, acidification, and subsequent death of the fungus.
Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors.
Flucloxacillin inhibits the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell wall of Gram-positive bacteria.
Trimethoprim inhibits bacterial dihydrofolate reductase.
Isoniazid decreases the synthesis of mycolic acids in mycobacteria.
-
This question is part of the following fields:
- Infections
- Pharmacology
-
-
Question 44
Correct
-
Which statement concerning aerosol transmission is true?
Your Answer: They can be spread via ventilation systems in hospitals
Explanation:Aerosols are airborne particles less than 5 µm in size containing infective organisms.
They usually cause infection of both the upper and/or lower respiratory tract.
The organisms can remain suspended in the air for long periods and also survive outside the body.
They can be transmitted through the ventilation systems and can spread over great distances.
Some examples of organisms transmitted by the aerosol route include: Varicella zoster virus, Mycobacterium tuberculosis and measles virus
-
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
-
-
Question 45
Correct
-
A 55 year old man presents to ED complaining of leg weakness. Your colleague has examined the patient and suspects femoral nerve palsy. Which of the following clinical features would you LEAST expect to see on examination of this patient:
Your Answer: Weakness of hip extension
Explanation:Damage to the femoral nerve results in weakness of hip flexion and knee extension and loss of sensation over the anterior thigh and the anteromedial knee, medial leg and medial foot.
-
This question is part of the following fields:
- Anatomy
- Lower Limb
-
-
Question 46
Correct
-
The term cardiac output refers to the amount of blood pumped by the heart in one minute. The rate in women is around 5 L/min, whereas in men is somewhat higher, around 5.5 L/min.
Which of the equations below best describes cardiac output?
Your Answer: Stroke volume x heart rate
Explanation:Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR):
CO = HR x SVAs a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.
-
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
-
-
Question 47
Incorrect
-
A 32-year-old woman diagnosed with hyperthyroidism has her T 4 levels grossly elevated and she is started on carbimazole.
A release of which of the following from the hypothalamus is inhibited by increase in T4 levels?Your Answer: Thyroid-stimulating hormone
Correct Answer: Thyrotropin-releasing hormone
Explanation:A negative feedback mechanism involving the hypothalamic-pituitary-thyroid axis controls the release of T3 and T4 into the bloodstream.
When metabolic rate is low or serum T3 and/or T4 levels are decrease, this triggers the secretion of thyrotropin-releasing hormone (TRH) from the hypothalamus.
TRH goes to the anterior pituitary gland and stimulates secretion of thyroid-stimulating hormone (TSH).
An increased serum level of T3 and T4 inhibits the release of TRH.
-
This question is part of the following fields:
- Endocrine Physiology
- Physiology
-
-
Question 48
Incorrect
-
The following are all important buffers of H+EXCEPT for:
Your Answer: Haemoglobin
Correct Answer: Calcium
Explanation:Buffers are weak acids or bases that can donate or accept H+ions respectively and therefore resist changes in pH. Buffering does not alter the body’s overall H+load, ultimately the body must get rid of H+by renal excretion if the buffering capacity of the body is not to be exceeded and a dangerous pH reached. Bicarbonate and carbonic acid (formed by the combination of CO2 with water, potentiated by carbonic anhydrase) are the most important buffer pair in the body, although haemoglobin provides about 20% of buffering in the blood, and phosphate and proteins provide intracellular buffering. Buffers in urine, largely phosphate, allow the excretion of large quantities of H+.
-
This question is part of the following fields:
- Physiology
- Renal
-
-
Question 49
Incorrect
-
Regarding Gaussian sample distribution, which of the following statements is false?
Your Answer: The median is the middle point of the observations
Correct Answer: It can be skewed left or right
Explanation:Gaussian distribution, also known as normal distribution, is the most important probability distribution in statistics because it fits many natural phenomena. The normal distribution is a probability function that describes how the values of a variable are distributed. Below are its characteristics:
(1) Bell-shaped and symmetrical about the mean
(2) The mean, median, mode are all equal
(3) The total area under the curve and above the x-axis is equal to 1
(4) It has long tapering tails extending infinitely but never touching the x-axis
(5) It is determined by its parameters: its mean and standard deviation
(6) The standard deviation becomes a more meaningful quality than merely being a measure of dispersionThe mean is the most common measure of central tendency. It is the sum of all observed values divided by the number of observation, and is also known as the ‘average’.
The median is the value that falls in the middle position when the observations are ranked in order from the smallest to the largest. If the number of observations is odd, the median is the middle number. If it is even, the median is the average of the two middle numbers.
The mode is the value that occurs with the greatest frequency in a set of observations, and is commonly used in public health statistics, such as the top 10 causes of mortality.
-
This question is part of the following fields:
- Evidence Based Medicine
-
-
Question 50
Correct
-
The pelvic bone is formed by which of the following:
Your Answer: Ilium, ischium and pubis
Explanation:Each pelvic bone is formed by three elements: the ilium (superiorly), the pubis (anteroinferiorly) and the ischium (posteroinferiorly).
-
This question is part of the following fields:
- Abdomen
- Anatomy
-
SESSION STATS - PERFORMANCE PER SPECIALTY
