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Question 1
Incorrect
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On her most recent blood tests, a 55 year-old female with a history of hypertension was discovered to be hypokalaemic. She  is diagnosed with primary hyperaldosteronism.Which of the following is a direct action of aldosterone?
Your Answer: Reabsorption of Na + into the proximal convoluted tubule
Correct Answer: Secretion of H + into the distal convoluted tubule
Explanation:Aldosterone is a steroid hormone produced in the adrenal cortex’s zona glomerulosa. It is the most important mineralocorticoid hormone in the control of blood pressure. It does so primarily by promoting the synthesis of Na+/K+ATPases and the insertion of more Na+/K+ATPases into the basolateral membrane of the nephron’s distal tubules and collecting ducts, as well as stimulating apical sodium and potassium channel activity, resulting in increased sodium reabsorption and potassium secretion. This results in sodium conservation, potassium secretion, water retention, and a rise in blood volume and blood pressure.Aldosterone is produced in response to the following stimuli:Angiotensin II levels have risen.Potassium levels have increased.ACTH levels have risen.Aldosterone’s principal actions are as follows:Na+ reabsorption from the convoluted tubule’s distal endWater resorption from the distal convoluted tubule (followed by Na+)Cl is reabsorbed from the distal convoluted tubule.K+ secretion into the convoluted distal tubule’s H+ secretion into the convoluted distal tubule’sÂ
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 2
Incorrect
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All of the statements regarding vascular tone are correct except:
Your Answer: Most types of vascular smooth muscle do not generate action potentials, but instead depolarisation is graded, allowing graded entry of Ca2+.
Correct Answer: Most endogenous vasodilators act by decreasing levels of cAMP or cGMP.
Explanation:Most vasoconstrictors bind to G-protein coupled receptors. These mediate elevation in intracellular [Ca2+] which leads to vascular smooth muscle contraction. Important vasoconstrictors include noradrenaline, endothelin-1 and angiotensin II. Increased intracellular Ca2+ is as a result of the release of Ca2+from the sarcoplasmic reticulum and depolarisation and entry of Ca2+via L-type voltage-gated Ca2+channels. Most types of vascular smooth muscle do not generate action potentials – instead, the depolarisation is graded, which allows graded entry of Ca2+.sequestration by the sarcoplasmic reticulum Ca2+ATPase, removal from the cell by a plasma membrane Ca2+ATPase and Na+/Ca2+exchange decreases intracellular Ca2+, resulting in vasodilation. Relaxation is a result of most endogenous vasodilators when there is an increase in cyclic guanosine monophosphate (cGMP) like nitric oxide) or cyclic adenosine monophosphate (cAMP) like prostacyclin and beta-adrenergic receptor agonists. These activate protein kinases causing substrate level phosphorylation. Clinically effective vasodilators are L-type Ca2+channel blocker drugs.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 3
Correct
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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: 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.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 4
Incorrect
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A patient presents with a history of renal problems, generalised weakness and palpitations. Her serum potassium levels are measured and come back at 6.2 mmol/L. An ECG is performed, and it shows some changes that are consistent with hyperkalaemia.Which of the following ECG changes is usually the earliest sign of hyperkalaemia? Select ONE answer only.
Your Answer: Prolonged PR segment
Correct Answer: Peaked T waves
Explanation:Hyperkalaemia causes a rapid reduction in resting membrane potential leading to increased cardiac depolarisation and muscle excitability. This in turn results in ECG changes which can rapidly progress to ventricular fibrillation or asystole. Very distinctive ECG changes that progressively change as the K+level increases:K+>5.5 mmol/l – peaked T waves (usually earliest sign of hyperkalaemia), repolarisation abnormalitiesK+>6.5 mmol/l – P waves widen and flatten, PR segment lengthens, P waves eventually disappearK+>7.0 mmol/l – Prolonged QRS interval and bizarre QRS morphology, conduction blocks (bundle branch blocks, fascicular blocks), sinus bradycardia or slow AF, development of a sine wave appearance (a pre-terminal rhythm)K+>9.0 mmol/l – Cardiac arrest due to asystole, VF or PEA with a bizarre, wide complex rhythm.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 5
Incorrect
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The following all cause a right shift in the oxygen dissociation curve EXCEPT for:
Your Answer: Increase in PCO 2
Correct Answer: Foetal haemoglobin
Explanation:A decreased affinity of haemoglobin for oxygen (and hence increased ease of dissociation), shown by a right shift in the oxygen dissociation curve, is caused by a fall in pH, a rise in PCO2(the Bohr effect) and an increase in temperature. These changes occur in metabolically active tissues such as in exercise, and encourage oxygen release. The metabolic by-product 2,3-diphosphoglycerate (2,3 -DPG) also causes a right shift; 2, 3 -DPG may also be raised in chronic anaemia, chronic lung disease, or at high altitude. Foetal haemoglobin (HbF) binds 2, 3 -DPG less strongly than does adult haemoglobin (HbA), and so the HbF dissociation curve lies to the left of that for HbA, reflecting its higher oxygen affinity. This helps transfer oxygen from mother to foetus.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 6
Correct
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Osteoclasts are a type of bone cell that are critical in the maintenance, repair and remodelling of bones.Which of the following inhibits osteoclast activity? Select ONE answer only.
Your Answer: Calcitonin
Explanation:Osteoclasts are a type of bone cell that breaks down bone tissue. This is a critical function in the maintenance, repair and remodelling of bones. The osteoclast disassembles and digests the composite of hydrated protein and minerals at a molecular level by secreting acid and collagenase. This process is known as bone resorption and also helps to regulate the plasma calcium concentration.Osteoclastic activity is controlled by a number of hormones:1,25-dihydroxycholecalciferol increases osteoclastic activityParathyroid hormone increases osteoclastic activityCalcitonin inhibits osteoclastic activityBisphosphonates are a class of drug that slow down and prevent bone damage. They are osteoclast inhibitors.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 7
Correct
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Antidiuretic hormone (ADH) levels are found to be increased in a young lady with unexplained hyponatraemia.In a healthy patient under normal circumstances, in which of the following conditions would ADH not be released?Â
Your Answer: Increased alcohol intake
Explanation:Antidiuretic hormone (ADH) is produced in the hypothalamus’s supraoptic nucleus and then released into the blood via axonal projections from the hypothalamus to the posterior pituitary.It is carried down axonal extensions from the hypothalamus (the neurohypophysial capillaries) to the posterior pituitary, where it is kept until it is released, after being synthesized in the hypothalamus.The secretion of ADH from the posterior pituitary is regulated by numerous mechanisms:Increased plasma osmolality: Osmoreceptors in the hypothalamus detect an increase in osmolality and trigger ADH release.Hypovolaemia causes a drop in atrial pressure, which stretch receptors in the atrial walls and big veins detect (cardiopulmonary baroreceptors). ADH release is generally inhibited by atrial receptor firing, but when the atrial receptors are stretched, the firing reduces and ADH release is promoted.Hypotension causes baroreceptor firing to diminish, resulting in increased sympathetic activity and ADH release.An increase in angiotensin II stimulates angiotensin II receptors in the hypothalamus, causing ADH production to increase.Nicotine, Sleep, Fright, and Exercise are some of the other elements that might cause ADH to be released.Alcohol (which partly explains the diuretic impact of alcohol) and elevated levels of ANP/BNP limit ADH release.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 8
Incorrect
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The proximal convoluted tubule (PCT) is the first part of the renal tubule and lies in the renal cortex. The bulk of reabsorption of solute occurs is the PCT and 100% of glucose is reabsorbed here.Which of the following is the mechanism of glucose reabsorption in the PCT?
Your Answer: Facilitated diffusion
Correct Answer: Secondary active transport
Explanation:Glucose reabsorption occurs exclusively in the proximal convoluted tubule by secondary active transport through the Na.Glu co-transporters, driven by the electrochemical gradient for sodium. The co-transporters transport two sodium ions and one glucose molecule across the apical membrane, and the glucose subsequently crosses the basolateral membrane by facilitated diffusion.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 9
Correct
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A 49-year-old woman has a history of hypertension and persistent hypokalaemia and is diagnosed with hyperaldosteronism.Which of these is the commonest cause of hyperaldosteronism?
Your Answer: Adrenal adenoma
Explanation:When there are excessive circulating levels of aldosterone, hyperaldosteronism occurs. There are two main types of hyperaldosteronism:Primary hyperaldosteronism (,95% of cases)Secondary hyperaldosteronism (,5% of cases)Primary causes of hyperaldosteronism include:Adrenal adenoma (Conn’s syndrome) Adrenal hyperplasiaAdrenal cancerFamilial aldosteronismSecondary causes of hyperaldosteronism include:DrugsObstructive renal artery disease Renal vasoconstrictionOedematous disorders syndrome Adrenal adenoma is the commonest cause of hyperaldosteronism (seen in ,80% of all cases).
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 10
Incorrect
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A 60-year-old patient with a history of hypertension and chronic kidney disease (CKD) walks into the clinic to discuss her most recent blood results indicating an accelerated progression of CKD.Which of the following is the correct definition for accelerated progression of CKD?
Your Answer: A sustained decrease in GFR of 15% or more within 12 months
Correct Answer: A sustained decrease in GFR of 15 ml/minute/1.73 m 2 per year
Explanation:Chronic kidney disease (CKD) is a disorder in which kidney function gradually deteriorates over time. It’s fairly prevalent, and it typically remains unnoticed for years, with only advanced stages of the disease being recognized. There is evidence that medication can slow or stop the progression of CKD, as well as lessen or prevent consequences and the risk of cardiovascular disease (CVD).CKD is defined as kidney damage (albuminuria) and/or impaired renal function (GFR 60 ml/minute per 1.73 m2) for three months or longer, regardless of clinical diagnosis.A prolonged decline in GFR of 25% or more with a change in GFR category within 12 months, or a sustained drop in GFR of 15 ml/minute/1.73 m² per year, is considered accelerated CKD progression.End-stage renal disease (ESRD) is defined as severe irreversible kidney impairment with a GFR of less than 15 ml/minute per 1.73 m² and a GFR of less than 15 ml/minute per 1.73 m².
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 11
Correct
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A 50-year-old man presents with headaches, lethargy, hypertension, and electrolyte disturbance. A diagnosis of primary hyperaldosteronism is made.Which biochemical pictures would best support this diagnosis?
Your Answer: Hypokalaemic metabolic alkalosis
Explanation:When there are excessive levels of aldosterone outside of the renin-angiotensin axis, primary hyperaldosteronism occurs. High renin levels will lead to secondary hyperaldosteronism. The classical presentation of hyperaldosteronism when symptoms are present include:HypokalaemiaMetabolic alkalosisHypertensionNormal or slightly raised sodium levels
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 12
Correct
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A 59-year-old man presents with a goitre, increased sweating, weight loss, and palpitations. A diagnosis of hyperthyroidism is suspected.What is the most appropriate first-line investigation?
Your Answer: TSH level
Explanation:A thyroid function test is used in the diagnosis of hyperthyroidism.Serum TSH should be the first-line investigation for patients with suspected hyperthyroidism as it has the highest sensitivity and specificity for hyperthyroidism. A normal TSH level almost always excludes the diagnosis, though there are rare exceptions to this.Antithyroglobulin antibodies are commonly present in Graves’ disease, but the test has a sensitivity of 98% and specificity of 99, and is not widely available.Radioactive iodine uptake scan using iodine-123 – shows low uptake in thyroiditis but high in Graves’ disease and toxic multinodular goitre. It is however, not first-line investigation in this caseThyroid ultrasound scan – is a cost-effective and safe alternative to the radioactive iodine uptake scan.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 13
Correct
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A patient with Conn’s syndrome will experience which of the following clinical features?
Your Answer: Hypernatraemia
Explanation:Conditions to consider in the differential diagnosis of primary aldosteronism or Conn’s syndrome include hypertension, metabolic alkalosis, hypokalaemia, hypernatremia, and low renin levels.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 14
Correct
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An infection causes an Addisonian crisis in a male patient with a known history of Addison's disease.Which of the following is NOT a well-known symptom of an Addisonian crisis?
Your Answer: Hyperglycaemia
Explanation:Although Addisonian crisis is a rare illness, it can be fatal if it is misdiagnosed. Hypoglycaemia and shock are the most common symptoms of an Addisonian crisis (tachycardia, peripheral vasoconstriction, hypotension, altered conscious level, and coma).Other clinical characteristics that may be present are:FeverPsychosisLeg and abdominal painDehydration and vomitingConvulsionsÂ
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 15
Correct
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Gastric emptying is inhibited by all of the following EXCEPT for:
Your Answer: Parasympathetic stimulation
Explanation:Gastric emptying is decreased by: Enterogastric inhibitory reflexes stimulated by – Distension of the duodenum, The presence of fats in the duodenum (by stimulating release of cholecystokinin), A fall in the pH of chyme in the duodenum, An increase in the osmolality of chyme in the duodenum, Irritation of the mucosal lining of the duodenum, Hormones: Cholecystokinin, Secretin
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 16
Correct
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A 33 year old female patient presents to emergency room with some symptoms that she thinks might be due to a drug that she has recently started. She was started on hyoscine butyl bromide for symptomatic relief of irritable bowel syndrome. The least likely expected side effect of this drug in this patient is:
Your Answer: Diarrhoea
Explanation:One of the commonest antispasmodic medications that is used is hyoscine butylbromide. It is an antimuscarinic and typical side effects of this class of drugs include:- dilation of pupils with loss of accommodation (cycloplegia) -photophobia resulting in blurred vision (Blind as a bat) -dry mouth, eyes and skin (Dry as a bone), -elevated temperature (Hot as a hare)-skin flushing (Red as a beet)-confusion or agitation particularly in the elderly (Mad as a hatter)-reduced bronchial secretions-transient bradycardia followed by tachycardia, palpitation and arrhythmias-urinary retention and/or constipation
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 17
Correct
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Which of the following is NOT a mineralocorticoid effect of corticosteroids:
Your Answer: Hyperglycaemia
Explanation:Mineralocorticoid side effects include:hypertensionsodium retentionwater retention and oedemapotassium losscalcium lossGlucocorticoid side effects include:weight gainhyperglycaemia and diabetesosteoporosis and osteoporotic fracturesmuscle wasting (proximal myopathy)peptic ulceration and perforationpsychiatric reactions
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 18
Incorrect
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The ventilation over perfusion ratio is highest at the apex of the lung. What is the approximate V/Q ratio at this area?
Your Answer: 1.2
Correct Answer: 3.3
Explanation:The ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the matching ventilation and perfusion. The ideal V/Q ratio is 1.Any mismatch between ventilation and perfusion will be evident in the V/Q ratio. If perfusion is normal but ventilation is reduced, the V/Q ratio will be less than 1, whereas if ventilation is normal, but perfusion is reduced, the V/Q ratio will be greater than 1. If the alveoli were ventilated but not perfused at all, then the V/Q ratio would be infinity. The V/Q ratio is also affected by location. The various areas of the lungs have a different V/Q ratio since ventilation and perfusion increase from the apex to the base of the lungs. The apex of the lungs has a V/Q ratio of approximately 3.3.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 19
Correct
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Adenosine has a half-life of approximately:
Your Answer: 8 - 10 seconds
Explanation:Adenosine stimulates A1-adenosine receptors and opens acetylcholine sensitive K+ channels, increasing K+ efflux. This hyperpolarises the cell membrane in the atrioventricular node and, by inhibiting the calcium channels, slows conduction in the AVN. As it has a very short duration of action (half-life only about 8 – 10 seconds), most side effects are short lived.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 20
Correct
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Regarding hypertensive crises, which of the following statements is CORRECT:
Your Answer: In a hypertensive emergency, blood pressure should be reduced by 20 - 25% within 2 hours.
Explanation:A hypertensive emergency is defined as severe hypertension (blood pressure ≥ 180/110 mmHg) with acute damage to the target organs. Prompt treatment with intravenous antihypertensive therapy is generally required; over the first few minutes or within 2 hours, blood pressure should be reduced by 20 – 25%. Severe hypertension without acute target organ damage is defined as hypertensive urgency.; blood pressure should be reduced gradually over 24 – 48 hours with oral antihypertensive therapy. If blood pressure is reduced too quickly in the management of hypertensive crises, there is a risk of reduced organ perfusion leading to cerebral infarction, blindness, deterioration in renal function, and myocardial ischaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 21
Incorrect
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Which of the following is NOT a typical side effect of digoxin:
Your Answer: Diarrhoea
Correct Answer: Hypokalaemia
Explanation:Digoxin does not cause hypokalaemia, but hypokalaemia does potentiate digoxin toxicity. The adverse effects of digoxin are frequently due to its narrow therapeutic window and include: Cardiac adverse effects – Sinoatrial and atrioventricular block, Premature ventricular contractions, PR prolongation and ST-segment depressionNausea, vomiting and diarrhoeaBlurred or yellow visionCNS effects – weakness, dizziness, confusion, apathy, malaise, headache, depression, psychosisThrombocytopenia and agranulocytosis (rare)Gynaecomastia in men in prolonged administration
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 22
Incorrect
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Insulin binds to the insulin receptor (IR) on cell surfaces to exert its action. The IR is a very specific transmembrane receptor belonging to the tyrosine kinase receptor class.One of these also activates the IR:
Your Answer: Somatostatin
Correct Answer: IGF-I
Explanation:Insulin receptor (IR), in addition to being activated by insulin, is also activated by IGF-I and IGF-II.The IR is a dimer with two identical subunits spanning the cell membrane and are connected by a single disulphide bond. The two sub-units include: The alpha chain situated on the exterior of the cell membrane and the beta chain spanning the cell membrane in a single segment. When insulin is detected, the alpha chains move together folding around the insulin making the beta chains move together, converting them into an active tyrosine kinase. This initiates a phosphorylation cascade increasing the expression of GLUT4 and allowing uptake of glucose by cells.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 23
Incorrect
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Which of the following is NOT a common side effect of amiodarone:
Your Answer: Peripheral neuropathy
Correct Answer: Blue/green teeth discolouration
Explanation:Common side effects of amiodarone include: Bradycardia, Nausea and vomiting, Thyroid disorders – hypothyroidism and hyperthyroidism, Persistent slate grey skin discoloration, Photosensitivity, Pulmonary toxicity (including pneumonitis and fibrosis), Hepatotoxicity, Corneal microdeposits (sometimes with night glare), Peripheral neuropathy and Sleep disorders.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 24
Incorrect
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In ventricular myocytes, the plateau phase of the action potential comes about through which of the following:
Your Answer: Closing of voltage-gated Na + channels
Correct Answer: Opening of voltage-gated Ca 2+ channels
Explanation:After the intial upstroke of the action potential, Na+channels and currents rapidly inactivate, but in cardiac myocytes, the initial depolarisation activates voltage-gated Ca2+channels (slow L-type channels, threshold approximately – 45 mV) through which Ca2+floods into the cell. The resulting influx of Ca2+prevents the cell from repolarising and causes a plateau phase, that is maintained for about 250 ms until the L-type channels inactivate. The cardiac AP is thus much longer than that in nerve or skeletal muscle.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 25
Incorrect
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A 70 year old man who has a previous history of small cell lung cancer was found to have severe hyponatraemia on a recent blood test and he is sent to the emergency room. In the nephron, where is the likely cause of this abnormality?
Your Answer: Proximal Tubule
Correct Answer: Distal nephron
Explanation:In the cancer patient, hyponatremia is usually caused by the syndrome of inappropriate antidiuretic hormone (SIADH). This develops more frequently with small cell lung cancer (SCLC) than with other malignancies. The pathogenesis of this is as a result of the process whereby ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, resulting in elevation of cAMP levels. Increased cAMP levels cause fusion of intracellular vesicles with the apical membrane. There are water channels called aquaporins in their membranes of these vesicles, and these increase the water permeability, thus facilitating increased water reabsorption and urine concentration. Thus, by increasing water retention, ADH causes blood to be diluted, which then decreases the concentration of solutes like sodium.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Correct
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All of the following statements are incorrect about insulin except:
Your Answer: Proinsulin is cleaved into insulin and C peptide.
Explanation:Proinsulin is synthesised as a single-chain peptide. A connecting peptide (C peptide) within storage granules is removed by proteases to yield insulin. Insulin:1. is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds. 2. is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas. 3. release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin. However, most output is driven by the rise in plasma glucose concentration that occurs after a meal. 4. effects are mediated by the receptor tyrosine kinase.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 27
Incorrect
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A 70-year-old patient diagnosed with Cushing's syndrome, has a history of weight gain, hypertension, and easy bruising.Which of the following statements about Cushing's syndrome is NOTÂ true?Â
Your Answer: Diagnosis can be confirmed by a 24-hour urinary free cortisol collection
Correct Answer: Menorrhagia is a common feature
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids.Iatrogenic corticosteroid injection is the most prevalent cause of Cushing’s syndrome.Cortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater throughout the 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed.Insulin resistance causes hyperglycaemia, which is a frequent symptom. Insulin resistance can produce acanthosis nigricans in the axilla and around the neck, as well as other skin abnormalities.In contrast to menorrhagia, elevated testosterone levels are more likely to produce amenorrhoea or oligomenorrhoea. Infertility in women of reproductive age can also be caused by high androgen levels.A dexamethasone suppression test or a 24-hour urine free cortisol collection can both be used to establish the existence of Cushing’s syndrome.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 28
Correct
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Which of the following causes the first heart sound?
Your Answer: Closing of the atrioventricular valves
Explanation:The heart sounds are as a result of the various parts of the cardiac cycle.Heart Sound – Phase of Cardiac Cycle – Mechanical Event:1st heart sound – Systole starts – there is closure of the atrioventricular (mitral & tricuspid) valves2nd heart sound – Systole ends – there is closure of the semilunar (aortic and pulmonary) valves3rd heart sound – Early diastole – this is caused by rapid flow of blood from the atria into the ventricles during the ventricular filling phase4th heart sound – Late diastole – this is caused by filling of an abnormally stiff ventricle in atrial systole
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 29
Incorrect
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Which of the following is a clinical effect of hyperkalaemia:
Your Answer: Hyperreflexia
Correct Answer: Muscle weakness
Explanation:Clinical features of hyperkalaemia may include: paraesthesia, muscle weakness or paralysis, cardiac conduction abnormalities and dysrhythmias. Clinical features of hypokalaemia may include: muscle weakness, muscle cramps, rhabdomyolysis and myoglobinuria, ascending paralysis resulting in respiratory failure, constipation, gut ileus with distension, anorexia, nausea and vomiting, impaired ADH action with polyuria and polydipsia, ECG changes and cardiac arrhythmias.
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This question is part of the following fields:
- Physiology
- Renal
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Question 30
Correct
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What is the partial pressure of oxygen if it makes up 20.9 percent of the ambient air composition and the atmospheric pressure of ambient air is 760 mmHg?
Your Answer: 159 mmHg
Explanation:Ambient air is atmospheric air in its natural state. Ambient air is typically 78.6% nitrogen and 20.9% oxygen. The extra 1% is made up of carbon, helium, methane, argon and hydrogen. The partial pressure of any gas can be calculated using this formula: P = atmospheric pressure (760 mmHg) x percent content in the mixture. Atmospheric pressure is the sum of all of the partial pressures of the atmospheric gases added together: The formula for atmospheric pressure is: Patm = PN2 + PO2 + PH2O + PCO2. The atmospheric pressure is known to be 760 mmHg. The partial pressures of the various gases can be estimated to have partial pressures of approximately 597.4 mmHg for nitrogen, 158.8 mm Hg for oxygen, and 7.6 mmHg for argon.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 31
Incorrect
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In the small intestine, there is a deep gap between each villus that leads to the crypt of LieberkĂĽhn, a tubular intestinal gland.What is the primary function of these glands?
Your Answer: Secretion of cholecystokinin
Correct Answer: Production of an alkaline intestinal juice
Explanation:In the small intestine, there is a deep gap between each villus that leads to the crypt of LieberkĂĽhn, a tubular intestinal gland. These glands create an alkaline intestinal juice that is a mixture of water and mucus with a pH of 7.4-7.8. Intestinal juice is released in a volume of 1-2 litres per day in response to distention of the small intestine or the irritating effects of chyme on the intestinal mucosa.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 32
Correct
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The renal corpuscle, consisting of the Bowman's capsule and the glomerulus is found where in the kidney:
Your Answer: The cortex
Explanation:All nephrons have their renal corpuscles in the renal cortex. Cortical nephrons have their renal corpuscles in the outer part of the cortex and relatively short loops of Henle. Juxtamedullary nephrons have their corpuscles in the inner third of the cortex, close to the corticomedullary junction, with long loops of Henle extending into the renal medulla.
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This question is part of the following fields:
- Physiology
- Renal
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Question 33
Correct
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Question 34
Correct
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The Auerbach's plexus is a set of ganglia that controls peristalsis and is located in the gut wall.Auerbach's plexus is located in which layer of the gut wall?Â
Your Answer: Muscular layer
Explanation:The Auerbach’s plexus, also known as the myenteric plexus, is a collection of ganglia that controls peristalsis and is located in the gut wall.In the muscular layer of the wall, it is located between the circular and longitudinal muscle layers. It is a linear network of linked neurons that runs the length of the gastrointestinal system. The myenteric plexus generates an increase in gut wall tone and the strength of rhythmical contractions when stimulated.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 35
Correct
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Which of the following is NOT a typical electrolyte disturbance caused by furosemide:
Your Answer: Hypercalcaemia
Explanation:Adverse effects of loop diuretics include:Mild gastrointestinal disturbances, pancreatitis and hepatic encephalopathyHyperglycaemiaAcute urinary retentionWater and electrolyte imbalanceHyponatraemia, hypocalcaemia, hypokalaemia, hypomagnesaemia, hypochloraemiaHypotension, hypovolaemia, dehydration, and venous thromboembolismMetabolic alkalosisHyperuricaemiaBlood disorders (bone marrow suppression, thrombocytopenia, and leucopenia)Visual disturbance, tinnitus and deafnessHypersensitivity reactions
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 36
Correct
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Which of the following drugs is first line treatment for a stable regular broad-complex tachycardia:
Your Answer: Amiodarone
Explanation:A regular broad-complex tachycardia is likely to be ventricular tachycardia or a regular supraventricular rhythm with bundle branch block. A ventricular tachycardia (or broad-complex tachycardia of uncertain origin) should be treated with amiodarone 300 mg IV over 10 – 60 min, followed by an infusion of 900 mg over the next 24 hours. If previously confirmed as SVT with bundle branch block, the patient should be treated as for narrow-complex tachycardia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 37
Incorrect
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You're evaluating a male patient who's having a lung function test done. In calculating the patient’s functional residual capacity, what parameters should you add to derive the functional residual capacity volume?
Your Answer: Expiratory reserve volume + tidal volume
Correct Answer: Expiratory reserve volume + residual volume
Explanation:The volume of air that remains in the lungs after a single breath is known as functional residual capacity (FRC). It is calculated by combining the expiratory reserve volume and residual volume.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 38
Correct
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When treating diabetic ketoacidosis (DKA), which of the following should be given if the systolic blood pressure is initially less than 90 mmHg:
Your Answer: 500 mL sodium chloride 0.9% intravenous infusion over 10 - 15 minutes
Explanation:If SBP is less than 90 mmHg , 500 mL sodium chloride 0.9 percent should be administered intravenously over 10–15 minutes, and repeated if SBP remains less than 90 mmHg. When SBP is greater than 90 mmHg, sodium chloride infusion must be maintained at a rate that replaces the deficit.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 39
Correct
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Which of the following statements is INCORRECT. Fick's law tells us that the rate of diffusion of a gas across a membrane increases as:
Your Answer: the partial pressure gradient decreases.
Explanation:Fick’s law tells us that the rate of diffusion of a gas increases: the larger the surface area involved in gas exchangethe greater the partial pressure gradient across the membranethe thinner the membranethe more soluble the gas in the membranethe lower the molecular weight of the gas
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 40
Correct
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Glucagon may be used as an antidote for overdose with which of the following:
Your Answer: Beta blockers
Explanation:Glucagon is a peptide hormone that is produced and secreted by alpha cells of the islets of Langerhans, which are located in the endocrine portion of the pancreas. The main physiological role of glucagon is to stimulate hepatic glucose output, thereby leading to increases in glycaemia. It provides the major counter-regulatory mechanism to insulin in maintaining glucose homeostasis.Hypoglycaemia is the principal stimulus for the secretion of glucagon but may also be used as an antidote in beta-blocker overdose and in anaphylaxis in patients on beta-blockers that fail to respond to adrenaline. Glucagon then causes:GlycogenolysisGluconeogenesisLipolysis in adipose tissueThe secretion of glucagon is also stimulated by:AdrenalineCholecystokininArginineAlanineAcetylcholineThe secretion of glucagon is inhibited by:InsulinSomatostatinIncreased free fatty acidsIncreased urea productionGlycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released by this process is used to form ATP and NADH. Glycolysis is inhibited by glucagon, and glycolysis and gluconeogenesis are reciprocally regulated so that when one cell pathway is activated, the other is inactive and vice versa.Glucagon has a minor effect of enhancing lipolysis in adipose tissue. Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into glycerol and free fatty acids. It makes fatty acids available for oxidation.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 41
Correct
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The renin-angiotensin-aldosterone system (RAAS) controls blood pressure and fluid balance.Which of the following sites produces the most angiotensinogen?Â
Your Answer: The liver
Explanation:Angiotensinogen is an alpha-2-globulin generated predominantly by the liver and released into the blood. Renin, which cleaves the peptide link between the leucine and valine residues on angiotensinogen, converts it to angiotensin I.Angiotensinogen levels in the blood are raised by:Corticosteroid levels have risen.Thyroid hormone levels have risen.Oestrogen levels have risen.Angiotensin II levels have risen.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 42
Incorrect
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Which of the following is NOT one of insulin's actions:
Your Answer: Increased glycogenesis
Correct Answer: Increased gluconeogenesis
Explanation:Insulin has a number of effects on glucose metabolism, including:Inhibition of glycogenolysis and gluconeogenesisIncreased glucose transport into fat and muscleIncreased glycolysis in fat and muscleStimulation of glycogen synthesisBy inhibiting gluconeogenesis, insulin maintains the availability of amino acids as substrates for protein synthesis. Thus, insulin supports protein synthesis through direct and indirect mechanisms.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 43
Correct
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Regarding the partial pressure of gases, which of the following statements is INCORRECT:
Your Answer: At high altitude, the oxygen fraction is reduced.
Explanation:At altitude, the oxygen fraction is unaltered but the barometric pressure and thus partial pressure of oxygen is reduced.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 44
Correct
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Captopril should not be used if you have any of the following conditions:
Your Answer: Renal artery stenosis
Explanation:Contraindications indications of Captopril include:- Bilateral renal artery stenosis- Hypersensitivity to ACE inhibitors- Anuria- History of ACEI-induced angioedema- Hereditary or idiopathic angioedema- Co-administration of Neprilysin inhibitors (e.g., sacubitril) with ACE inhibitors may increase angioedema risk; do not administer ACE inhibitors within 36 hours of switching to or from sacubitril/valsartan.If ACE inhibitors are used, they should be initiated only under specialist supervision and renal function should be monitored regularly. ACE inhibitors should also be used with particular caution in patients who may have undiagnosed and clinically silent renovascular disease. This includes patients with peripheral vascular disease or those with severe generalised atherosclerosis.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 45
Correct
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A 59-year-old man presents with increased sweating, weight loss, and palpitations. A series of blood tests done found a very low TSH level and a diagnosis of hyperthyroidism is made.What is the commonest cause of hyperthyroidism?
Your Answer: Graves’ disease
Explanation:Hyperthyroidism results from an excess of circulating thyroid hormones. It is commoner in women, and incidence increases with age.Hyperthyroidism can be subclassified into:Primary hyperthyroidism – the thyroid gland itself is affectedSecondary hyperthyroidism – the thyroid gland is stimulated by excessive circulating thyroid-stimulating hormone (TSH).Graves’ disease is the most common cause of hyperthyroidism (estimates are that it causes between 50 and 80% of all cases).Although toxic multinodular goitre, thyroiditis,TSH-secreting pituitary adenoma and drug-induced hyperthyroidism also causes hyperthyroidism, the commonest cause is Graves’ disease.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 46
Correct
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In the treatment of hypertensive episodes in pheochromocytoma, which of the following medication types is administered as first-line management:
Your Answer: Alpha-blockers
Explanation:The first line of management in controlling blood pressure and preventing intraoperative hypertensive crises is to use a combination of alpha and beta-adrenergic inhibition. In phaeochromocytoma, alpha-blockers are used to treat hypertensive episodes in the short term. Tachycardia can be managed by the careful addition of a beta-blocker, preferably a cardioselective beta-blocker, once alpha blockade has been established. Long term management of pheochromocytoma involves surgery.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 47
Correct
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Which of the following hormones is dysfunctional in diabetes insipidus:
Your Answer: Antidiuretic hormone
Explanation:Diabetes insipidus (DI) may result from a deficiency of ADH secretion (cranial DI) or from an inappropriate renal response to ADH (nephrogenic DI). As a result, fluid reabsorption at the kidneys is impaired, resulting in large amounts of hypotonic, dilute urine being passed with a profound unquenchable polydipsia.The biochemical hallmarks of DI are:High plasma osmolality (> 295 mOsm/kg)Low urine osmolality (< 300 mOsm/kg)Hypernatraemia (> 145 mmol/L)High urine volume
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 48
Correct
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Which of the following conditions require IV Lidocaine administration?
Your Answer: Refractory ventricular fibrillation in cardiac arrest
Explanation:IV Lidocaine is indicated in Ventricular Arrhythmias or Pulseless Ventricular Tachycardia (after defibrillation, attempted CPR, and vasopressor administration)
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 49
Correct
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A 71-year-old patient has been diagnosed with a dopamine-secreting neuroendocrine tumour.Which of the following statements about dopamine is correct?
Your Answer: It inhibits prolactin release from the anterior pituitary
Explanation:Dopamine is a neurotransmitter and amine hormone that is derived from the amino acid tyrosine. It is made in a number of places throughout the human body, both inside and outside the central nervous system. The adrenal medulla, dopamine neurons in the arcuate nucleus of the hypothalamus, the substantia nigra, and other areas of the brain produce dopamine.The tuberoinfundibular pathway refers to the dopamine neurons in the arcuate nucleus of the hypothalamus’ tubeal region. Dopamine is discharged into the hypothalamo-hypophyseal portal system from these neurons’ neurosecretory terminals at the median eminence.The major function of dopamine produced from the hypothalamus is to suppress prolactin production from the anterior pituitary, and it is released in reaction to excessive levels of prolactin secretion. Modulation of motor-control centres and activation of reward centres are two more crucial activities of the brain.Dopamine-secreting cells can also be found in other areas of the body, where they perform mostly paracrine functions (acting on nearby cells).
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 50
Incorrect
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A 67-year-old man with chronic breathlessness is sent for a lung function test.Which statement concerning lung function testing is true?
Your Answer: Spirometry is a good predictor of quality of life in COPD
Correct Answer: In restrictive lung disease, the FEV 1 /FVC ratio is usually >0.7
Explanation:In restrictive lung disease, the FEV1/FVC ratio is usually >0.7%.In obstructive lung disease, FEV1 is reduced to <80% of normal and FVC is usually reduced. The FEV1/FVC ratio is reduced to 80% in the presence of symptomsModerate airflow obstruction = FEV 1 of 50-79%Severe airflow obstruction = FEV 1 of 30-49%Very severe airflow obstruction = FEV1<30%.Spirometry is a poor predictor of quality of life in COPD. However, it can be used as part of the assessment of severity of COPD.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
