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Question 1
Correct
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Question 2
Correct
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A 59-year-old man presents to the emergency room with chest pain. He was recently released from the hospital after receiving abciximab during coronary angioplasty.
Which of the following is abciximab (ReoPro) mechanism of action?Your Answer: Antagonism of the glycoprotein IIb/IIIa receptor
Explanation:Abciximab (ReoPro) is a glycoprotein IIb/IIIa receptor antagonist that is a chimeric monoclonal antibody. It is primarily used during and after coronary artery procedures such as angioplasty to inhibit platelet aggregation.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 3
Correct
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An analytical cohort study aimed to determine a relationship between intake of dietary calcium and incidence of hip fractures among post-menopausal women. The following are the data obtained from the study:
No. of post-menopausal women who took Calcium: 500
No. of post-menopausal women who took Calcium and suffered a hip fracture: 10
No. of post-menopausal women who took placebo: 500
No. of post-menopausal women who took placebo and suffered a hip fracture: 25
Compute for the risk ratio of a hip fracture.Your Answer: 0.4
Explanation:Relative risk (RR) is a ratio of the probability of an event occurring in the exposed group versus the probability of the event occurring in the non-exposed group.
RR can be computed as the absolute risk of events in the treatment group (ART), divided by the absolute risk of events in the control group (ARC).
RR = ART/ARC
RR = (10/500) / (25/500)
RR = 0.4Recall that:
If RR < 1, then the intervention reduces the risk of the outcome.
If RR = 1, then the treatment has no effect on the outcome.
If RR > 1, then the intervention increases the risk of the outcome. -
This question is part of the following fields:
- Evidence Based Medicine
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Question 4
Incorrect
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An elderly man presents with bilateral lower facial swelling around the mandible and upper neck. A CT scan of his neck was performed and the results were conclusive with Ludwig's angina.
Which of the following spaces is most likely affected based on the case presented?Your Answer: Submental space
Correct Answer: Submandibular space
Explanation:Ludwig’s angina is life-threatening cellulitis of the soft tissue involving the floor of the mouth and neck. It involves three compartments of the floor of the mouth: the sublingual, submental, and submandibular.
Ludwig’s angina usually originates as a dental infection of the second or third mandibular molars. The infection begins in the subgingival pocket and spreads to the musculature of the floor of the mouth. It progresses below the mylohyoid line, indicating that it has moved to the sublingual space. As the roots of the second and third mandibular molars lie below this line, infection of these teeth will predispose to Ludwig’s angina. The infection spreads lingually rather than buccally because the lingual aspect of the tooth socket is thinner. It initially spreads to the sublingual space and progresses to the submandibular space.
The disease is usually polymicrobial, involving oral flora, both aerobes, and anaerobes. The most common organisms are Staphylococcus, Streptococcus, Peptostreptococcus, Fusobacterium, Bacteroides, and Actinomyces.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 5
Correct
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A 28-year-old patient who has been in a car accident needs to be intubated using a rapid sequence induction. As an induction agent, you intend to use etomidate.
Etomidate works by interacting with which type of receptor?Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Etomidate is a carboxylated imidazole derivative with a short half-life that is primarily used to induce anaesthesia.
It is thought to modulate fast inhibitory synaptic transmission in the central nervous system by acting on GABA type A receptors.
The dose for anaesthesia induction is 0.3 mg/kg. Etomidate takes 10-65 seconds to take effect after an intravenous injection, and it lasts 6-8 minutes. With repeated administration, the effects are non-cumulative.The relative cardiovascular stability of etomidate is noteworthy. During induction, it causes less hypotension than thiopental sodium and propofol. It’s also linked to a quick recovery without the hangover.
Etomidate is a strong steroidogenesis inhibitor. The drug inhibits the enzymes responsible for adrenal 11 beta-hydroxylase and cholesterol cleavage, resulting in a decrease in cortisol and aldosterone synthesis for up to 24 hours after administration. It should not be used to maintain anaesthesia because of the adrenocortical suppression.
Other side effects associated with etomidate use include:
Vomiting and nausea
The injection causes pain (in up to 50 percent )
Phlebitis and thrombosis of the veins
Heart block and arrhythmias
Hyperventilation
Apnoea and respiratory depression
It has the potential to cause both hypo- and hypertension.
Critically ill patients have a higher mortality rate. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
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 exchange
the greater the partial pressure gradient across the membrane
the thinner the membrane
the more soluble the gas in the membrane
the lower the molecular weight of the gas -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 7
Correct
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You are reviewing a patient complaining of loss of vision. Previous images shows a lesion at the optic chiasm. What type of visual field defect are you most likely to see in a lesion at the optic chiasm:
Your Answer: Bitemporal hemianopia
Explanation:A lesion at the optic chiasm will result in a bitemporal hemianopia.
A lesion of the optic nerve will result in ipsilateral monocular visual loss.
A lesion of the optic tract will result in a contralateral homonymous hemianopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 8
Incorrect
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Lidocaine's antiarrhythmic mode of action is as follows:
Your Answer: Blocks open Na+ channels
Correct 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.
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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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Angiotensin II is part of the RAAS system. One of its effects is the constriction of efferent arterioles. Which of the following best describes the effect of angiotensin II- mediated constriction of efferent arterioles?
Your Answer: Decreased renal plasma flow, decreased filtration fraction, decreased GFR
Correct Answer: Decreased renal plasma flow, increased filtration fraction, increased GFR
Explanation:The Renin-Angiotensin-Aldosterone System (RAAS) is a hormone system composed of renin, angiotensin, and aldosterone. Those hormones are essential for the regulation of blood pressure and fluid balance.
Cases of hypotension, sympathetic stimulation, or hyponatremia can activate the Renin-angiotensin-aldosterone system (RAAS). The following process will then increase the blood volume and blood pressure as a response.
When renin is released it will convert the circulating angiotensinogen to angiotensin I. The ACE or angiotensin-converting enzyme will then catalyst its conversion to angiotensin II, which is a potent vasoconstrictor. Angiotensin II can constrict the vascular smooth muscles and the efferent arteriole of the glomerulus.
The efferent arteriole is a blood vessel that delivers blood away from the capillaries of the kidney. The angiotensin II-mediated constriction of efferent arterioles increases GFR, reduces renal blood flow and peritubular capillary hydrostatic pressure, and increases peritubular colloid osmotic pressure, as a response to its action of increasing the filtration fraction.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 10
Incorrect
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Which of the following is NOT an advantage of a case-control study used to identify past exposure to a risk factor in patients with a disease:
Your Answer: Relative quick, cheap and easy to perform
Correct Answer: Can directly measure absolute and relative risk of a disease
Explanation:Advantages:relatively quickrelatively cheap and easy to performparticularly suitable for studying associations between an exposure and an outcome when the outcome is uncommon or if the outcome occurs decades after exposurea wide range of risk factors can be investigated in each studyDisadvantages:subject to recall biasunlike in a whole population study, absolute risk cannot be quantifiedtemporal relationship between exposure and outcome can be difficult to establishunsuitable for rare risk factorsprone to confounding
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 11
Correct
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A patient has suffered a nerve injury that has caused weakness of the pectoralis minor muscle.
Pectoralis minor receives its innervation from which of the following nerves? Select ONE answer only.Your Answer: Medial pectoral nerve
Explanation:Pectoralis minor is a thin, triangular muscle that is situated in the upper chest. It is thinner and smaller than pectoralis major. It is innervated by the medial pectoral nerve.
The origin of pectoralis minor is the 3rdto the 5thribs, near the costal cartilages. It inserts into the medial border and superior surface of the coracoid process of the scapula.
The main action of pectoralis minor is to draw the scapula inferiorly and anteriorly against the thoracic wall. This serves to stabilise the scapula. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 12
Correct
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A p value < 0.05 obtained from a study with a significance level (α) of 0.05, means all of the following, EXCEPT:
Your Answer: the result is clinically significant.
Explanation:A p value < 0.05:is statistically significantmeans that the probability of obtaining a given result by chance is less than 1 in 20means the null hypothesis is rejectedmeans there is evidence of an association between a variable and an outcomeNote that this does not tell us whether the result is clinically significant.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 13
Incorrect
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Which of the following organisms can penetrate intact skin:
Your Answer: Streptococcus pyogenes
Correct Answer: Leptospira spp.
Explanation:Leptospirosis is a bacterial disease caused byLeptospira spp. It is the most common zoonotic infection worldwide.
It is usually contracted by exposure to water contaminated with the urine of infected animals (such as rodents, cattle, and dogs). The most important reservoirs are rodents, and rats are the most common source worldwide.
The bacteria enter the body through the skin or mucous membranes. This is more likely if the skin is broken by leptospirosis is somewhat unusual in that it can enter the body through intact skin. -
This question is part of the following fields:
- Microbiology
- Principles
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Question 14
Incorrect
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A 50-year-old man presents with signs and symptoms of an anaphylactic reaction. His GP had recently given him a new medication.
Which one of these is the most likely medication responsible for the drug-induced anaphylactic reaction?
Your Answer: Ramipril
Correct Answer: Penicillin
Explanation:The most common cause of drug-induced anaphylaxis is penicillin.
The second commonest cause are NSAIDs. Other drugs associated with anaphylaxis are ACE inhibitors and aspirin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 15
Correct
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A patient has an elevated potassium level of 6.7 mmol/L. All of the following conditions may cause elevated potassium levels, except for which one?
Your Answer: Bartter’s syndrome
Explanation:Bartter’s syndrome is an autosomal recessive renal tubular disorder characterized by hypokalaemia, hypochloraemia, metabolic alkalosis, and hyperreninemia with normal blood pressure. The underlying kidney abnormality results in excessive urinary losses of sodium, chloride, and potassium.
Bartter’s syndrome does not cause an elevated potassium level, but instead causes a decrease in its concentration (hypokalaemia). The other choices are causes of hyperkalaemia or elevated potassium levels.
Renal failure, Addison’s disease (adrenal insufficiency), congenital adrenal hyperplasia, renal tubular acidosis (type 4), rhabdomyolysis, burns and trauma, tumour syndrome, and acidosis are non-drug causes of hyperkalaemia. On the other hand, drugs that can cause hyperkalaemia include ACE inhibitors, angiotensin receptor blockers, NSAIDs, beta-blockers, digoxin, and suxamethonium.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 16
Incorrect
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Regarding protein digestion, which of the following statements is CORRECT:
Your Answer: Amino acids cross the basal membrane of the enterocyte into the capillaries by simple diffusion.
Correct Answer: Oligopeptides are broken down into small peptides and amino acids by pancreatic carboxypeptidases and aminopeptidases located on the brush border.
Explanation:Digestion of dietary protein begins in the stomach where pepsin hydrolyses protein to polypeptides, and continues in the duodenum where pancreatic proteases (trypsin and chymotrypsin) continue the process of hydrolysis forming oligopeptides. These are further broken down into small peptides and amino acids by pancreatic carboxypeptidases and aminopeptidases located on luminal membrane epithelial cells. Free amino acids are absorbed across the apical membrane by secondary active transport coupled with Na+transport into the cell. Amino acids cross the basal membrane into the capillaries by facilitated diffusion.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 17
Incorrect
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A 62-year-old female complains of pain in her right upper quadrant. An abdominal ultrasound is conducted, and a big gallstone is discovered. The radiologist who performs the scan speaks with you about the physiology of the gallbladder and biliary tract.
During a 24-hour period, how much bile does the gallbladder produce?
Your Answer: 200-400 ml
Correct Answer: 400-800 ml
Explanation:The gallbladder stores and concentrates bile, which is produced by the liver. In a 24-hour period, around 400 to 800 mL of bile is generated. The breakdown of fats into fatty acids, the removal of waste materials, and cholesterol homeostasis are all crucial functions of bile.
Bile is created on a constant basis, however it is only necessary after a meal has been consumed. The elimination of water and ions concentrates bile in the gallbladder, which is subsequently stored for later use. Food induces the release of the hormone cholecystokinin from the duodenum, the contraction of the gallbladder, and the relaxation of the sphincter of Oddi. The bile then enters the duodenum.
Bile acids have a hydrophobic and hydrophilic area, making them amphipathic. Bile acids’ amphipathic nature allows them to perform the following crucial functions:
Emulsification of lipid aggregates increases the surface area of fat and makes it easier for lipases to digest it.
Lipid solubilization and transport: solubilizes lipids by creating micelles, which are lipid clumps that float in water.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 18
Correct
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A 45-year-old obese patient goes to the emergency department with a fever and significant right upper quadrant pain. The pain radiates to her right shoulder tip. Murphy's sign is positive and acute cholecystitis is diagnosed. The pain referred to the shoulder tip is caused by one of the following nerves:
Your Answer: Phrenic nerve
Explanation:Gallbladder inflammation can cause pain in the right upper quadrant and right shoulder, which is caused by irritation of the diaphragmatic peritoneum. Pain from areas supplied by the phrenic nerve is often referred to other somatic regions served by spinal nerves C3-C5.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 19
Correct
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Blood flows from the left atrium into the left ventricle via:
Your Answer: The mitral valve
Explanation:Blood flows from the right atrium into the right ventricle via the tricuspid atrioventricular valve and from the left atrium into the left ventricle via the mitral atrioventricular valve. Blood is ejected from the right ventricle through the pulmonary semilunar valve into the pulmonary artery and from the left ventricle via the aortic semilunar valve into the aorta.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 20
Incorrect
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Pressure across the wall of a flexible tube (the transmural pressure) increases wall tension and extends it.
Which law best describes transmural pressure?
Your Answer: Starling’s law
Correct Answer: Laplace’s law
Explanation:The transmural pressure (pressure across the wall of a flexible tube) can be described by Laplace’s law which states that:
Transmural pressure = (Tw) / r
Where:
T = Wall tension
w = Wall thickness
r = The radius
A small bubble with the same wall tension as a larger bubble will contain higher pressure and will collapse into the larger bubble if the two meet and join.Fick’s law describes the rate of diffusion in a solution
Poiseuille’s law is used to calculate volume of flow rate in laminar flow
Darcy’s law describes the flow of a fluid through a porous medium.
Starling’s law describes cardiac haemodynamics as it relates to myocyte contractility and stretch.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 21
Correct
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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.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 22
Correct
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Which of the following best describes the main sites of constriction of the ureters:
Your Answer: At the ureteropelvic junction, at the pelvic brim and where the ureters enter the bladder
Explanation:At three points along their course, the ureters are constricted denoting the most likely areas for renal calculi to lodge:the first point is at the ureteropelvic junction (where the renal pelvis becomes continuous with the ureter)the second point is where the ureter crosses the common iliac vessels at the pelvic brimthe third point is at the vesicoureteric junction (where the ureter enters the wall of the bladder)
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 23
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 24
Correct
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Depolarisation of a neuron begins with which of the following:
Your Answer: Opening of ligand-gated Na + channels
Explanation:Action potentials are initiated in nerves by activation of ligand-gated Na+channels by neurotransmitters. Opening of these Na+channels results in a small influx of sodium and depolarisation of the negative resting membrane potential (-70 mV). If the stimulus is sufficiently strong, the resting membrane depolarises enough to reach threshold potential (generally around -55 mV), at which point an action potential can occur. Voltage-gated Na+channels open, causing further depolarisation and activating more voltage-gated Na+channels and there is a sudden and massive sodium influx, driving the cell membrane potential to about +40 mV.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 25
Correct
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In the ventricular myocyte action potential, depolarisation occurs through the opening of:
Your Answer: Voltage-gated Na + channels
Explanation:An action potential (AP) is initiated when the myocyte is depolarised to a threshold potential of about -65 mV, as a result of transmission from an adjacent myocyte via gap junctions. Fast voltage-gated Na+channels are activated and a Na+influx depolarises the membrane rapidly to about +30 mV. This initial depolarisation is similar to that in nerve and skeletal muscle, and assists the transmission to the next myocyte.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 26
Correct
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Regarding acute lymphoblastic leukaemia (ALL), which of the following statements is CORRECT:
Your Answer: 75% of cases occur before the age of 6 years.
Explanation:Acute lymphoblastic leukaemia (ALL) is caused by an accumulation of lymphoblasts in the bone marrow and is the most common malignancy of childhood. The incidence of ALL is highest at 3 – 7 years, with 75% of cases occurring before the age of 6. 85% of cases are of B-cell lineage. Haematological investigations reveal a normochromic normocytic anaemia with thrombocytopenia in most cases. There is great variation in the chance of individual patients achieving a long-term cure based on a number of biological variables. Approximately 25% of children relapse after first-line therapy and need further treatment but overall 90% of children can expect to be cured. The cure rate in adults drops significantly to less than 5% over the age of 70 years.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 27
Incorrect
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Loop diuretics primarily act on which Na+ transporter?
Your Answer: Na + /K + ATPase pump
Correct Answer: Na + /K + /2Cl - symporter
Explanation:The most potent diuretics are loop diuretics e.g. furosemide. They work by inhibiting the Na+/K+/2Cl-symporter in the thick ascending limb of the loop of Henle, which inhibits sodium, potassium, and chloride reabsorption. As a result, there is diuresis with loss of these electrolytes. There is a reduction in transcellular voltage difference, paracellular calcium and magnesium reabsorption.
The medullary interstitium becomes more concentrated by salt reabsorption in the ascending limb. Loop diuretics block this process and reduce the ability of the kidney to concentrate urine. In the collecting duct, there is increased sodium delivery to the principal cells, which increases potassium secretion in return for sodium reabsorption. -
This question is part of the following fields:
- Physiology
- Renal
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Question 28
Incorrect
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The following are all examples of type I hypersensitivity EXCEPT for:
Your Answer: Asthma
Correct Answer: Contact dermatitis
Explanation:Examples of type I reactions include:
Allergic rhinitis
Allergic conjunctivitis
Allergic asthma
Systemic anaphylaxis
Angioedema
Urticaria
Penicillin allergy -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 29
Incorrect
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Eosinophils comprise what percentage of circulating white cells:
Your Answer: 0.2
Correct Answer: 1 - 3%
Explanation:Eosinophils comprise 1 – 3% of circulating white cells. Eosinophils are similar to neutrophils, except that the cytoplasmic granules are coarser and more deeply red staining, and there are rarely more than three nuclear lobes. They are less motile, but longer lived. They enter inflammatory exudates and have a special role in allergic responses, defence against parasites and removal of fibrin formed during inflammation. Thus they play a role in local immunity and tissue repair.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 30
Correct
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Which of the following is NOT a side effect of phenytoin:
Your Answer: Ototoxicity
Explanation:Adverse effects of phenytoin include:
Nausea and vomiting
Drowsiness, lethargy, and loss of concentration
Headache, dizziness, tremor, nystagmus and ataxia
Gum enlargement or overgrowth
Coarsening of facial features, acne and hirsutism
Skin rashes
Blood disorders -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
