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Question 1
Incorrect
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Which law describes the rate of diffusion in a solution?
Your Answer: Laplace’s law
Correct Answer: Fick’s law
Explanation:Fick’s law describes the rate of diffusion in a solution. Fick’s law states that:Jx = -D A (ΔC / Δx)Where:Jx = The amount of substance transferred per unit timeD = Diffusion coefficient of that particular substanceA = Surface area over which diffusion occursΔC = Concentration difference across the membraneΔx = Distance over which diffusion occursThe negative sign reflects movement down the concentration gradient
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 2
Incorrect
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How does an action potential in the motor end plate rapidly spread to the central portions of the muscle cells?
Your Answer: Pores in the plasma membrane
Correct Answer: Transverse tubules
Explanation:When the concentration of intracellular Ca2+rises, muscle contraction occurs. The pathway of an action potential is down tube-shaped invaginations of the sarcolemma called T-tubules (transverse tubules). These penetrate throughout the muscle fibre and lie adjacent to the terminal cisternae of the sarcoplasmic reticulum. The voltage changes in the T-tubules result in the opening of sarcoplasmic reticulum Ca2+channels and there is there is release of stored Ca2+into the sarcoplasm. Thus muscle contraction occurs via excitation-contraction coupling (ECC) mechanism.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 3
Correct
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A 32-old woman comes for a follow-up visit after being discharged on medications for her newly diagnosed epilepsy. She now complains of a tremor in her arm when she holds a tray in her hand. You examine the patient and notice she has developed postural tremors. Which of the following medications for epilepsy is most likely responsible for this tremor?
Your Answer: Sodium valproate
Explanation:A postural tumour is observed when a person maintains a position against gravity, such as holding the arms outstretched. (The patient holding her tray against gravity) Sodium valproate is the most commonly prescribed medication for epilepsy. It is commonly associated with tremors as valproate-induced tremors occur in around 6-45% of patients. The tremors are commonly postural, but a resting tremor may also occur.Approximately 25% of patients taking sodium valproate are found to develop a tremor within 3-12 months of initiating therapy.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 4
Incorrect
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Atrial natriuretic peptide (ANP) acts to cause all of the following effects EXCEPT for:
Your Answer: Inhibits Na + reabsorption in the distal nephron
Correct Answer: Vasoconstricts the afferent arteriole
Explanation:ANP acts to: Inhibit Na+ reabsorption in the distal nephron (through inhibition of ENaC in principal cells)Suppress the production of reninSuppress the production of aldosteroneSuppress the production of ADHCause renal vasodilation, increasing the glomerular filtration rate
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This question is part of the following fields:
- Physiology
- Renal
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Question 5
Incorrect
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Which of the following local anaesthetics has the longest duration of action:
Your Answer:
Correct Answer: Bupivacaine
Explanation:Bupivacaine has a longer duration of action than the other local anaesthetics, up to 8 hours when used for nerve blocks. It has a slow onset, taking up to 30 minutes for full effect. It is often used in lumbar epidural blockade and is particularly suitable for continuous epidural analgesia in labour, or for postoperative pain relief. It is the principal drug used for spinal anaesthesia.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
Incorrect
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Regarding meningococcal meningitis, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Infection occurs most commonly below the age of 5 years.
Explanation:About half of meningococcal disease occurs in children aged less than five years, and babies are at the highest risk because their immune systems have not yet fully developed. There is a second, smaller increase in risk for older adolescents, mainly for social and behavioural reasons. Infection is most common in winter months. Antibiotics should be given as soon as the diagnosis is suspected (ideally cultures should be performed first but this should not delay treatment), and ceftriaxone/cefuroxime is the first line antibiotic. Only healthcare workers who have been directly exposed to large particle droplets/secretions from the respiratory tract of the index case should receive prophylaxis.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 7
Incorrect
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Mannitol is primarily indicated for which of the following:
Your Answer:
Correct Answer: Cerebral oedema
Explanation:Mannitol is an osmotic diuretic that can be used to treat cerebral oedema and raised intraocular pressure. Mannitol is a low molecular weight compound and is, therefore, freely filtered at the glomerulus and is not reabsorbed. It, therefore, increases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect. It also does not cross the blood-brain-barrier (BBB).
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Incorrect
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A patient who is taking ramipril for high blood pressure complains of a dry persistent cough. What is the mechanism of cough in ACE inhibitor therapy:
Your Answer:
Correct Answer: Decreased bradykinin breakdown
Explanation:Blocking ACE also diminishes the breakdown of the potent vasodilator bradykinin which is the cause of the persistent dry cough. Angiotensin-II receptor blockers do not have this effect, therefore they are useful alternative for patients who have to discontinue an ACE inhibitor because of persistent cough.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 9
Incorrect
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An very unwell patient is receiving treatment in your hospital's HDU and is found to have an Escherichia coli O157 infection.Which one of these statements about Escherichia coli O157 is true?
Your Answer:
Correct Answer: Haemolytic uraemic syndrome develops in approximately 6% of patients
Explanation:Escherichia coli O157 is a serotype of Escherichia coli.The Escherichia coliO157 strain is ‘enterohaemorrhagic’ and causes severe forms of acute haemorrhagic diarrhoea. It can also cause non-haemorrhagic diarrhoea. Incubation period of Escherichia coli O157 is usually 3-4 days and bloody diarrhoea usually begins on the 3rd or 4th day of the infection.Infections with Escherichia coliO157 are more common during the warmer months than in winter.Haemolytic uraemic syndrome develops in approximately 6% of patients. It is commonly seen in children and in the elderly. Escherichia coli O157 can also cause:Haemorrhagic colitisHaemolytic uraemic syndromeThrombotic thrombocytopenic purpura but not immune thrombocytopenic purpura.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 10
Incorrect
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You are seeing a child with known mitochondrial disease who has presented breathlessness and cough. Which of the following best describes the function of mitochondria:
Your Answer:
Correct Answer: Energy production
Explanation:Mitochondria are membrane-bound organelles that are responsible for the production of the cell’s supply of chemical energy. This is achieved by using molecular oxygen to utilise sugar and small fatty acid molecules to generate adenosine triphosphate (ATP). This process is known as oxidative phosphorylation and requires an enzyme called ATP synthase. ATP acts as an energy-carrying molecule and releases the energy in situations when it is required to fuel cellular processes. Mitochondria are also involved in other cellular processes, including Ca2+homeostasis and signalling. Mitochondria contain a small amount of maternal DNA.Mitochondria have two phospholipid bilayers, an outer membrane and an inner membrane. The inner membrane is intricately folded inwards to form numerous layers called cristae. The cristae contain specialised membrane proteins that enable the mitochondria to synthesise ATP. Between the two membranes lies the intermembrane space, which stores large proteins that are required for cellular respiration. Within the inner membrane is the perimitochondrial space, which contains a jelly-like matrix. This matrix contains a large quantity of ATP synthase.Mitochondrial disease, or mitochondrial disorder, refers to a group of disorders that affect the mitochondria. When the number or function of mitochondria in the cell are disrupted, less energy is produced and organ dysfunction results.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 11
Incorrect
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In the emergency room, a 28-year-old woman complains of wobbly and slurred speech, is unable to do the heel-shin test, and has nystagmus. The following signs are most likely related to damage to which of the following areas:
Your Answer:
Correct Answer: Cerebellum
Explanation:Cerebellar injury causes delayed and disorganized motions. When walking, people with cerebellar abnormalities sway and stagger. Damage to the cerebellum can cause asynergia, the inability to judge distance and when to stop, dysmetria, the inability to perform rapid alternating movements or adiadochokinesia, movement tremors, staggering, wide-based walking or ataxic gait, a proclivity to fall, weak muscles or hypotonia, slurred speech or ataxic dysarthria, and abnormal eye movements or nystagmus.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 12
Incorrect
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A well recognised adverse effect of metoclopramide is which of the following?
Your Answer:
Correct Answer: Acute dystonic reaction
Explanation:Side effects of metoclopramide are commonly associated with extrapyramidal effects and hyperprolactinemia. Therefore its use must be limited to short-term use. Metoclopramide can induce acute dystonic reactions which involve facial and skeletal muscle spasms and oculogyric crises. These dystonic effects are more common in the young girls and young women, and in the very old. These symptoms usually occur shortly after starting treatment with this drug and subside within 24 hours of stopping it. Abortion of dystonic attacks can be carried out by injection of an antiparkinsonian drug like procyclidine.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 13
Incorrect
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A young pregnant woman is in the late stages of her pregnancy. She is administered a drug that results in her newborn being born with respiratory depression. The baby also suffers from neonatal withdrawal syndrome.Out of the following, which drug is most likely responsible for the baby's condition?
Your Answer:
Correct Answer: Diazepam
Explanation:Benzodiazepines are used as a first-line treatment in breaking seizures and in status epilepticus as they are rapid-acting. Use of benzodiazepines in the late third-trimester or exposure during labour is associated with great risks to the foetus/neonate. Babies can exhibit either floppy infant syndrome, or marked neonatal withdrawal symptoms. Symptoms vary from mild sedation, hypotonia, and reluctance to suck, to apnoeic spells, cyanosis, and impaired metabolic responses to cold stress. These symptoms have been reported to persist for periods from hours to months after birth. They also cross into breast milk and should be used with caution in breastfeeding mothers
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 14
Incorrect
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You are about to perform an emergency pericardiocentesis on a 26-year-old male who was involved in a car accident and is suspected of having cardiac tamponade due to signs of hypotension, muffled heart sounds, and distended neck veins. Where should you insert the needle to relieve tamponade?
Your Answer:
Correct Answer: Inferior and to the left of the xiphochondral junction
Explanation:Pericardiocentesis is a procedure that removes excess fluid from the pericardium. As a result, it’s used in cases of cardiac tamponade, which occurs when there’s too much fluid in the space around the heart. During the procedure, a needle and a small catheter are inserted 1 to 2 cm inferior and to the left of the xiphochondral junction into the pericardial cavity.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 15
Incorrect
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Which of the following nerves is most important for eversion of the foot:
Your Answer:
Correct Answer: Superficial fibular nerve
Explanation:Eversion of the foot is primarily produced by the fibularis longus and fibularis brevis, both innervated by the superficial fibular nerve. The fibularis tertius, innervated by the deep fibular nerve, also assists in this action.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 16
Incorrect
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What is the main mechanism of action of flecainide:
Your Answer:
Correct Answer: Blocks Na+ channels
Explanation:Flecainide inhibits the transmembrane influx of extracellular Na+ ions via fast channels on cardiac tissues resulting in a decrease in rate of depolarisation of the action potential, prolonging the PR and QRS intervals. At high concentrations, it exerts inhibitory effects on slow Ca2+ channels, accompanied by moderate negative inotropic effect.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 17
Incorrect
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A 45-year-old woman presents with persistent palpitations for the past two days. She has a good haemodynamic balance. An ECG is performed, which reveals that she has atrial flutter. The patient is examined by a cardiology registrar, who recommends using a 'rate control' strategy while she waits for cardioversion.Which of the drugs listed below is the best fit for this strategy?
Your Answer:
Correct Answer: Bisoprolol
Explanation:In atrial flutter, ventricular rate control is usually used as a stopgap measure until sinus rhythm can be restored. A beta-blocker (such as bisoprolol), diltiazem, or verapamil can be used to lower the heart rate.Electrical cardioversion, pharmacological cardioversion, or catheter ablation can all be used to restore sinus rhythm. Cardioversion should not be attempted until the patient has been fully anticoagulated for at least three weeks if the duration of atrial flutter is unknown or has lasted for more than 48 hours. Emergency electrical cardioversion is the treatment of choice when there is an acute presentation with haemodynamic compromise. For the treatment of recurrent atrial flutter, catheter ablation is preferred.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 18
Incorrect
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A 71-year-old man treated with antibiotics for a chest infection returns with a profuse, offensive smelling diarrhoea. A diagnosis of Clostridium difficile diarrhoea is made after investigations.The action most effective at minimizing spread to other patients is?
Your Answer:
Correct Answer: Hand washing
Explanation:Clostridium difficile, a Gram-positive, anaerobic, spore forming bacteria is present in the gut of approximately 3% of healthy adults (2012 UK HPA estimates). Following use of broad spectrum antibiotics, which alter normal gut flora, Clostridium difficile associated diarrhoea (CDAD) occurs.Alcohol hand gel is not effective against Clostridium Difficile spores. Hand washing with soap and water is very essential for healthcare workers who come in contact with it.Wearing an apron and gloves, and isolation to a side room are important contact precautions. They are, however, ineffective if hand washing is neglected.Although oral vancomycin is the first-line treatment for C. difficile associated diarrhoea, it will not limit patient to patient spread.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 19
Incorrect
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Regarding bicarbonate handling by the proximal tubule, which of the following statements is CORRECT:
Your Answer:
Correct Answer: For each H + secreted into the lumen, one Na + and one HCO 3 - is reabsorbed into the plasma.
Explanation:About 80% of bicarbonate is reabsorbed in the proximal tubule. HCO3-is not transported directly, tubular HCO3-associates with H+secreted by epithelial Na+/H+antiporters to form carbonic acid (H2CO3) which readily dissociates to form carbon dioxide and water in the presence of carbonic anhydrase. CO2and water diffuse into the tubular cells, where they recombine to form carbonic acid which dissociates to H+and HCO3-. This HCO3-is transported into the interstitium largely by Na+/HCO3-symporters on the basolateral membrane (and H+is secreted back into the lumen). For each H+secreted into the lumen, one Na+and one HCO3-are reabsorbed into the plasma. H+is recycled so there is little net secretion of H+at this stage.
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This question is part of the following fields:
- Physiology
- Renal
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Question 20
Incorrect
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Which of the following side effects has limited the use of etomidate as an intravenous induction agent:
Your Answer:
Correct Answer: Adrenocortical suppression
Explanation:Etomidate causes the least cardiovascular depression of the intravenous induction agents, with only a small reduction in the cardiac output and blood pressure. In the past, etomidate was widely used to induce anaesthesia in the shocked, elderly or cardiovascularly unstable patient. However, more recently it has become less popular as a single induction dose blocks the normal stress-induced increase in adrenal cortisol production for 4 – 8 hours, and up to 24 hours in elderly and debilitated patients. Although no increase in mortality has been identified following a single dose during induction of anaesthesia, the use of etomidate has declined due to a perceived potential morbidity.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 21
Incorrect
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Regarding the resting membrane potential, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The resting cell membrane is more permeable to K + ions than to Na + ions.
Explanation:A membrane potential is a property of all cell membranes, but the ability to generate an action potential is only a property of excitable tissues. The resting membrane is more permeable to K+and Cl-than to other ions (and relatively impermeable to Na+); therefore the resting membrane potential is primarily determined by the K+equilibrium potential. At rest the inside of the cell is negative relative to the outside. In most neurones the resting potential has a value of approximately -70 mV.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 22
Incorrect
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Which of the following causes increased aldosterone secretion:
Your Answer:
Correct Answer: Decreased blood volume
Explanation:Decreased blood volume stimulates the secretion of renin (because of decreased renal perfusion pressure) and initiates the renin-angiotensin-aldosterone cascade. Angiotensin-converting enzyme (ACE) inhibitors block the cascade by decreasing the production of angiotensin. Hyperosmolarity stimulates antidiuretic hormone (ADH) [not aldosterone] secretion. Hyperkalaemia, not hypokalaemia, directly stimulates aldosterone secretion by the adrenal cortex. ANPÂ inhibits renin secretion, thereby inhibiting the production of angiotensin and aldosterone.
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This question is part of the following fields:
- Physiology
- Renal
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Question 23
Incorrect
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Which of the following is NOT a typical effect caused by adrenaline:
Your Answer:
Correct Answer: Bronchoconstriction
Explanation:Actions of adrenaline:Cardiovascular system- Increased rate and force of cardiac contraction- Vasoconstriction of vessels in skin, mucous membranes and splanchnic bed- Vasodilation of skeletal muscle vessels- Increased cardiac output and blood pressureRespiratory system- Bronchodilation- Increased ventilation rateGastrointestinal system- Smooth muscle relaxation- Contraction of sphincters- Metabolism- Decreased insulin release- Increased glucagon release- Increased thermogenesis- Increased glycolysis- Increased lipolysisEye- Pupillary dilation
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 24
Incorrect
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A type II error occurs when:
Your Answer:
Correct Answer: The null hypothesis is accepted when it is false.
Explanation:A type II error occurs when the null hypothesis is wrongly accepted when it is actually false and we conclude that there is no evidence of a difference in effect when one really exists (a false negative result).
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 25
Incorrect
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Antidiuretic hormone (ADH) is synthesised by which of the following:
Your Answer:
Correct Answer: Hypothalamus
Explanation:Antidiuretic hormone is synthesised in the hypothalamus and transported to the posterior pituitary within nerve fibres where it is stored in secretory granules. ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH) characterised by hyponatremia with concomitant hypo-osmolality and high urine osmolality.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Incorrect
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A 21 year old student presents to the emergency room with severe acute asthma. Salbutamol and ipratropium bromide nebuliser are prescribed. The most appropriate dose of salbutamol that should be prescribed initially for this patient is which of the following?
Your Answer:
Correct Answer: 5 mg every 15 - 30 minutes
Explanation:The first line treatment for acute asthma is high-dose inhaled short-acting beta2-agonists like salbutamol or terbutaline. Oxygen use should be reserved for hypoxemic patients in order to maintain oxygen saturations of 94 – 98%. In patients with moderate to severe asthma, a pressurised metered dose inhaler with spacer device is preferred (4 puffs initially, followed by 2 puffs every 2 minutes according to response, up to 10 puffs, whole process repeated every 10 – 20 minutes if necessary). For patients with life-threatening features or poorly responsive severe asthma, the oxygen-driven nebuliser route is recommended (salbutamol 5 mg at 15 – 30 minute intervals). In patients with severe acute asthma that is poorly responsive to initial bolus dose, continuous nebulisation should be considered (salbutamol at 5 – 10 mg/hour). For those in whom inhaled therapy cannot be used reliably, the intravenous route is usually reserved.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 27
Incorrect
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Which of the following is the most abundant immunoglobulin in plasma:
Your Answer:
Correct Answer: IgG
Explanation:IgA is the major Ig in secretions, particularly from the gastrointestinal tract (but also in saliva, tears, sweat and breast milk).IgE is important for mast cell degranulation in allergic and antiparasitic response. In the allergic response, the plasma cell produces IgE-antibodies, which, like antibodies of other immunoglobulin isotypes, are capable of binding a specific allergen via its Fab portion.IgG is the most abundant in plasma (comprising 80% of normal serum immunoglobulin) and the main circulatory Ig for the secondary immune response.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 28
Incorrect
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A dermatological examination of a patient presenting with a lump shows a visible collection of fluid measuring 0.3 cm in diameter.Which one of these best describes the lump you have found on examination?
Your Answer:
Correct Answer: Vesicle
Explanation:A vesicle is a visible collection of fluid measuring less than 0.5 cm in diameter.A furuncle, or boil, is a pyogenic infection of the hair follicle commonly caused by infection with Staphylococcus aureus. A carbuncle is a collection of individual boils clustered together. A bulla is a visible collection of clear fluid measuring greater than 0.5 cm in diameter. A pustule is a small visible skin elevation containing an accumulation of pus.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 29
Incorrect
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The only statement that is correct regarding diffusion is which of the following?
Your Answer:
Correct Answer: The permeability of a membrane is related to the membrane thickness and composition.
Explanation:Passive diffusion is a process that describes the movement down a concentration gradient. This process accounts for movement across small distances like within the cytosol or across membranes. Factors that affect the diffusion of a substance across a membrane are the permeability (p) of the membrane, a difference in concentration across the membrane and the membrane area over which diffusion occurs. The membrane thickness and composition, and the diffusion coefficient of the substance also affects the permeability. Fick’s law describes the rate of diffusion of a substance within a solution, which can be modified to describe the rate of diffusion across a membrane.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 30
Incorrect
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A 30-year-old male farmer presents to the Emergency Department due to a wound on his right forearm sustained two days ago while working on the farm. He cleaned the wound under a tap, but there was still some dirt and debris on examination. Past medical history reveals that he never received a tetanus vaccine. After cleaning the wound and prescribing antibiotics, which ONE of the following actions should be taken to manage his tetanus risk?
Your Answer:
Correct Answer: Tetanus vaccination and 500 IU tetanus immunoglobulin
Explanation:If a patient presents with one of the following types of wounds, they are at risk of contracting tetanus and should be vaccinated immediately:1) Contaminated puncture-type wounds from gardening and farming (as they may contain tetanus spores)2) Wounds containing foreign bodies3) Open (compound) fractures4) Wounds or burns with sepsis5) Animal bites and scratches (animal saliva does not contain tetanus spores unless the animal was routing in soil or lives in an agriculture setting)Extremely high-risk tetanus-prone wounds are any of the above wounds with one of the following:1) Any wound contaminated by materials containing tetanus spores, e.g., soil, manure2) Burns or wounds with extensive devitalised tissue3) Wounds or burns with surgical intervention delayed for more than six hours even if the initial injury was not heavily contaminatedThe CDC recommends that adults who have never been vaccinated for tetanus receive a quick shot of the tetanus vaccine along with a booster dose ten years later. A tetanus-prone wound in an unvaccinated individual should also receive a high dose of tetanus immunoglobulin. The injected antibodies will prevent tetanus infection as the patient does not have any pre-existing antibodies against the disease.In this case, the patient has a high risk, contaminated wound. He should receive a high dose of tetanus immunoglobulin along with the tetanus vaccine. (The preventative dose of tetanus immunoglobulin is 250 IU in most cases unless over 24 hours have passed since the injury or the wound is heavily contaminated, then 500 IU should be given.) His physician also needs to be contacted to arrange the remainder of the course as indicated in this case.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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SESSION STATS - PERFORMANCE PER SPECIALTY
