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Question 1
Incorrect
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer: Rate of diffusion is primarily dependent on the alveolar-capillary concentration gradient of O 2 and CO 2 .
Correct Answer: The rate of diffusion in lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs across a membrane and is therefore governed by Fick’s law. Although CO2is larger than O2, it is is much more soluble and diffuses 20 times more rapidly. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Incorrect
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A 68-year-old patient shows Low calcium levels and is on dialysis for chronic kidney disease.
What percentage of total serum calcium is in the form of free or ionised Ca 2+?Your Answer: 99%
Correct Answer: 50%
Explanation:Approximately half of total serum calcium is in the free or ionised Ca2+ state, 40% is attached to plasma proteins (mostly albumin), and the remaining 10% is in complexes with organic ions like citrate and phosphate. The ionized form is the only one that works.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 3
Incorrect
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Regarding benzodiazepines, which of the following statements is INCORRECT:
Your Answer: Lorazepam produces more prolonged sedation than temazepam and it has marked amnesic effects.
Correct Answer: Diazepam is a short-acting benzodiazepine.
Explanation:Diazepam is used to produce mild sedation with amnesia. It is a long-acting drug with active metabolites and a second period of drowsiness can occur several hours after its administration. Midazolam is a water-soluble benzodiazepine that is often used in preference to intravenous diazepam; recovery is faster than from diazepam, but may be significantly longer in the elderly, in patients with a low cardiac output, or after repeated dosing. Midazolam is associated with profound sedation when high doses are given intravenously or when it is used with certain other drugs.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 4
Incorrect
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Epigastric pain and haematemesis present in a 67-year-old man. In the emergency room, he is stabilised and referred to the on-call medical team. He has been scheduled for an endoscopy in the morning due to a suspected peptic ulcer. Before transferring him to the ward, you consider giving him a proton pump inhibitor (PPI).
Which of the following doses and routes are the best?Your Answer: Omeprazole 80 mg intravenously
Correct Answer: A PPI should not be prescribed
Explanation:PPIs should not be used prior to endoscopic therapy when an early endoscopic examination is performed within 24 hours of admission, according to current recommendations.
High-dose PPI therapy reduces the risk of rebleeding and surgery after endoscopic treatment of severe peptic ulcer bleeding. Both oral and intravenous PPIs produce similar results, and there is no discernible benefit to using the intravenous formulation in patients who can tolerate oral medication. -
This question is part of the following fields:
- Gastrointestinal Pharmacology
- Pharmacology
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Question 5
Incorrect
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For which of the following class of drugs can neostigmine be used as a reversal agent?
Your Answer: Barbiturates
Correct Answer: Non-depolarising muscle relaxants
Explanation:Neostigmine is used specifically for reversal of nondepolarizing (competitive) blockade and is anticholinesterase. It acts within one minute of intravenous injection, and the effects last for 20 to 30 minutes. After this time period, a second dose may then be necessary.
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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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Discontinuous capillaries are typically found where in the body:
Your Answer: Blood-brain barrier
Correct Answer: Reticuloendothelial system
Explanation:Discontinuous capillaries, found in the reticuloendothelial system (bone marrow, liver and spleen), have large gaps between endothelial cells and are permeable to red blood cells.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 7
Incorrect
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A 70-year-old man has severe diarrhoea one week after taking co-amoxiclav for a chest infection. The diarrhoea is yellow in colour and smell is offensive.
What is the SINGLE MOST likely causative organism?
Your Answer: Norovirus
Correct Answer: Clostridium difficile
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.
About 80% of Clostridium difficile infections are seen in people over the age of 65 and its main clinical features are:
Abdominal cramps, severe bloody and/or watery diarrhoea, offensive smelling diarrhoea, and fever. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 8
Incorrect
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Identify the type of graph described below:
A graph that consists of a vertical bar graph in which values are plotted in decreasing order of relative frequency from left to right. The independent variables on the chart are shown on the horizontal axis and the dependent variables are portrayed as the heights of bars.Your Answer: Histogram
Correct Answer: Pareto diagram
Explanation:A pareto diagram, or pareto chart, consists of a vertical bar graph in which values are plotted in decreasing order of relative frequency from left to right. The independent variables on the chart are shown on the horizontal axis and the dependent variables are portrayed as the heights of bars.
A point-to-point graph, which shows the cumulative relative frequency, may be superimposed on the bar.
Because the values of the statistical variables are placed in order of relative frequency, the graph clearly reveals which factors have the greatest impact and where attention is likely to yield the greatest benefit. It is extremely useful for analysing what problems need attention first, because the taller bars on the chart clearly illustrate which variable have the greatest cumulative effect on a given system.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 9
Incorrect
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Glomerular filtration rate can be calculated using any substance that:
Your Answer: is freely filtered and secreted by the nephron
Correct Answer: is freely filtered and neither reabsorbed nor secreted by the nephron
Explanation:Clearance of a substance can provide an accurate estimate of the glomerular filtration rate (GFR) provided that the substance is:freely filterednot reabsorbed in the nephronnot secreted in the nephronnot synthesised or metabolised by the kidney
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This question is part of the following fields:
- Physiology
- Renal
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Question 10
Incorrect
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Antispasmodic drugs are primarily indicated in which of the following conditions:
Your Answer: Bowel obstruction
Correct Answer: Irritable bowel syndrome
Explanation:Antispasmodics, such as antimuscarinics, may be used in the management of irritable bowel syndrome. Other antispasmodics used include direct-acting smooth muscle relaxants such as mebeverine, alverine, and peppermint oil. Antispasmodics are contraindicated in bowel obstruction and severe inflammatory bowel disease. Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects. Antimuscarinics are contraindicated in urinary retention.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 11
Incorrect
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A 40-year-old man complains of pain and redness in his lower thigh due to an insect bite. He was diagnosed with cellulitis. Select the first-line antibiotic for cellulitis.
Your Answer: Ciprofloxacin
Correct Answer: Flucloxacillin
Explanation:Cellulitis is most commonly caused by bacteria from the group Aß-hemolytic streptococcus.
Cellulitis can be caused by animal bites. For uncomplicated cellulitis, flucloxacillin is the first-line antibiotic. Because it is beta-lactamase stable, it is efficient against Staphylococcus aureus.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 12
Incorrect
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Naloxone is a reversal agent for which of the following groups of drugs:
Your Answer: Benzodiazepines
Correct Answer: Opioids
Explanation:Naloxone is a specific antagonist of mu(μ)-opioid receptors, the specific antidote for opioid overdose and will reverse respiratory depression and coma if given at sufficient dosage. The initial dose is usually 0.8 mg (2 mL) intravenously (the dose range suggested by BNF is 0.4-2 mg). It can also be given by intramuscular injection if the intravenous route is not feasible.
As naloxone has a shorter duration of action than most opioids, close monitoring and repeated injections are necessary according to the respiratory rate and depth of coma. The dose is generally repeated every 2-3 minutes to a maximum of 10 mg. When repeated doses are needed, naloxone may be given by a continuous infusion adjusted according to the vital signs. Initially, the infusion rate can be set at 60% of the initial resuscitative IV dose per hour.
In opioid addicts, naloxone administration may precipitate a withdrawal syndrome with abdominal cramps, nausea and diarrhoea, but these usually settle within 2 hours. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 13
Correct
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The myocardium is responsible for creating the force with which the atrial and ventricular muscles contract. It is made up of myocytes, which are heart muscle cells.
Which of the following statements about cardiac muscle anatomy is correct?Your Answer: Cardiac myocytes have intercalated discs
Explanation:Typically, granuloma has Langerhan’s cells (large multinucleated cells ) surrounded by epithelioid cell aggregates, T lymphocytes and fibroblasts.
Antigen presenting monocytic cells found in the skin are known as Langerhan’s cells.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 14
Incorrect
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Foetal haemoglobin (HbF) comprises about how much of the total haemoglobin in adults:
Your Answer: 0 - 0.001%
Correct Answer: 0.5 - 0.8%
Explanation:Foetal haemoglobin (HbF) makes up about 0.5 – 0.8 % of total adult haemoglobin and consists of two α and two gamma (γ) globin chains.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 15
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: Fluoxetine
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 16
Incorrect
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A 70-year-old patient develops bacteraemia following peripheral cannulation.
Which of these bacteria is the most likely cause of the infection?Your Answer: Streptococcus pyogenes
Correct Answer: Staphylococcus epidermidis
Explanation:The commonest implicated organisms in hospital-acquired bacteraemia following cannulation are Staphylococcus aureus and Staphylococcus epidermidis.
The risk is directly proportional to the length of time in-situ. Peripheral cannula should be replaced after 48 hours. -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 17
Incorrect
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Regarding apoptosis, which of the following statements is INCORRECT:
Your Answer: Apoptosis is mediated by activation of a caspase cascade.
Correct Answer: Apoptosis leads to cell swelling and eventual cell lysis.
Explanation:Apoptosis is a controlled form of cell death in which no cellular contents are released from the dying cell, and thus no inflammatory reaction is seen. Apoptosis may occur physiologically or pathologically. Apoptosis may be induced in two main ways: by the engagement of surface death receptors e.g. TNF-alpha (extrinsic pathway) or through cellular injury (intrinsic pathway). The end result is the activation of proteases enzymes called caspases which dismantle the cell cytoplasm and nucleus. Apoptotic cells shrink down and fragment into apoptotic bodies, each of which retains an intact cell membrane; apoptotic bodies are then targeted or rapid removal by adjacent cells. Disordered apoptosis is thought to be central to a number of important disease processes, particularly carcinogenesis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 18
Incorrect
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The weight distribution in a group of patients included in a study was normal. The patients averaged 80 kg in weight. 5 kg was determined to be the standard deviation. Which of the following statements most accurately describes this group of patients:
Your Answer: 99% of the patients will weigh between 70 and 90 kg.
Correct Answer: 68% of the patients will weigh between 75 and 85 kg.
Explanation:We can estimate the range of values that would be anticipated to include particular proportions of observations if we know the mean and standard deviation of a collection of normally distributed data: 68.2 percent of the sample results fall within a one SD range above and below the mean (+/- 1 SD), implying that 68 percent of the patients will weigh between 75 and 85 kg. Because +/- 2 SD encompasses 95.4 percent of the data, around 95 percent of the patients will weigh between 70 and 90 kg. +/- 3 SD encompasses 99.7% of the values, implying that nearly all of the patients will weigh between 65 and 95 kg.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 19
Incorrect
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A 56-year-old female visits her cardiologist complaining of a condition that has started since he started her on amiodarone for atrial arrhythmia. The cardiologist recognised that she is experiencing a side effect of amiodarone.
Which one of the following conditions will this woman NOT have?Your Answer: Hypothyroidism
Correct Answer: Xanthopsia
Explanation:Amiodarone is a class III potassium channel blocker used to treat multiple types of arrhythmias.
Side effects include:
1. pulmonary fibrosis
2. blue discolouration of the skin
3. phototoxicity
4. corneal deposits
5. hepatic necrosis
6. thyroid dysfunction
7. sleep disturbances
8. peripheral neuropathy.Xanthopsia is a condition where the patient complains of seeing yellow lines and is seen in digoxin overdose.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 20
Incorrect
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A 70-year-old patient is diagnosed with Cushing's disease. She has a history of weight gain, hypertension, and easy bruising.
In this patient, which of the following is the MOST LIKELY UNDERLYING CAUSE?Your Answer: Ectopic corticotropin syndrome
Correct Answer: Pituitary adenoma
Explanation:Cushing’s syndrome is a collection of symptoms and signs caused by prolonged exposure to elevated levels of either endogenous or exogenous glucocorticoids.
The most common cause of Cushing’s syndrome is the iatrogenic administration of corticosteroids. The second most common cause of Cushing’s syndrome is Cushing’s disease.
Cushing’s disease should be distinguished from Cushing’s syndrome and refers to one specific cause of the syndrome, an adenoma of the pituitary gland that secretes large amounts of ACTH and, in turn, elevates cortisol levels. This patient has a diagnosis of Cushing’s disease, and this is, therefore, the underlying cause in this case.
The endogenous causes of Cushing’s syndrome include:
Pituitary adenoma (Cushing’s disease)
Ectopic corticotropin syndrome, e.g. small cell carcinoma of the lung
Adrenal hyperplasia
Adrenal adenoma
Adrenal carcinoma -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 21
Incorrect
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Question 22
Correct
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A 2nd-year medical student is solving an exam paper with questions about the immune system. She comes across a question regarding innate immunity. Innate immunity is the immunity naturally present within the body from birth.
Which ONE of the following is not a part of this type of immunity?Your Answer: Antibody production
Explanation:Innate immunity, also called non-specific immunity, refers to the components of the immune system naturally present in the body at birth.
The components of innate immunity include:
1) Natural Killer Cells
2) Neutrophils
3) Macrophages
4) Mast Cells
5) Dendritic Cells
6) Basophils.Acquired or adaptive immunity is acquired in response to infection or vaccination. Although the response takes longer to develop, it is also a more long-lasting form of immunity.
The components of this system include:
1) T lymphocytes
2) B lymphocytes
3) Antibodies -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 23
Correct
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On reviewing the ECG of a patient with a history of intermittent palpitations, you observe prolonged QT interval.
Which of these can cause prolongation of the QT interval on the ECG?
Your Answer: Erythromycin
Explanation:Syncope and sudden death due to ventricular tachycardia, particularly Torsades-des-pointes is seen in prolongation of the QT interval.
The causes of a prolonged QT interval include:
Erythromycin
Amiodarone
Quinidine
Methadone
Procainamide
Sotalol
Terfenadine
Tricyclic antidepressants
Jervell-Lange-Nielsen syndrome (autosomal dominant)
Romano Ward syndrome (autosomal recessive)
Hypothyroidism
Hypocalcaemia
Hypokalaemia
Hypomagnesaemia
Hypothermia
Rheumatic carditis
Mitral valve prolapse
Ischaemic heart disease -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 24
Incorrect
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A 54-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.
Which of the following is the patient's preferred drug treatment?Your Answer: 10% of the systolic pressure over the first hour
Correct Answer: 25% of the mean arterial pressure over the first hour
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.
Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.
Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.
The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.
An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 25
Incorrect
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Which of the following does NOT increase free ionised calcium levels:
Your Answer: Activated vitamin D
Correct Answer: Calcitonin
Explanation:Calcium homeostasis is primarily controlled by three hormones: parathyroid hormone, activated vitamin D and calcitonin.
Parathyroid hormone acts on the kidneys to increase calcium reabsorption in the distal tubule by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane (and to decrease phosphate reabsorption in the proximal tubule).
Activated vitamin D acts to increase calcium reabsorption in the distal tubule via activation of a basolateral Ca2+ATPase pump (and to increase phosphate reabsorption).
Calcitonin acts to inhibit renal reabsorption of calcium (and phosphate).
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This question is part of the following fields:
- Physiology
- Renal
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Question 26
Incorrect
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The tetanus vaccination contains inactivated tetanus toxoid, which induces the body to produce protective antibodies. How do these antibodies protect the body from tetanus?
Your Answer: Bind C. tetani flagella preventing cell motility and access to neurons
Correct Answer: Neutralise the protein exotoxin of C. tetani
Explanation:C. Tetanospasmin, an exotoxin produced by tetani, is responsible for the neurotoxic consequences of tetanus.
The tetanus vaccination contains inactivated tetanus toxoid, which induces the body to produce protective antibodies that neutralize the tetanus toxin.
It induces active immunization against Clostridium tetani exotoxin via toxoid-induced Ab generation.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 27
Incorrect
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What is the main mechanism of action of dobutamine as an inotropic sympathomimetic:
Your Answer: Beta2-receptor agonist
Correct Answer: Beta1-receptor agonist
Explanation:Dobutamine directly stimulates the beta1-adrenergic receptors in the heart and increases contractility and cardiac output with little effect on the rate. In addition action on beta2-receptors causes vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 28
Incorrect
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Which of the following antibiotics may be used for malaria prophylaxis:
Your Answer: Phenoxymethylpenicillin
Correct Answer: Doxycycline
Explanation:Doxycycline may be used for malaria prophylaxis and as an adjunct to quinine in the treatment of Plasmodium falciparum malaria.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 29
Incorrect
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A tumour compresses the jugular foramen of a 50-year-old patient. Compression of several nerves in the jugular foramen will result in which of the following complications?
Your Answer: Loss of tongue movements
Correct Answer: Loss of gag reflex
Explanation:The glossopharyngeal nerve, which is responsible for the afferent pathway of the gag reflex, the vagus nerve, which is responsible for the efferent pathway of the gag reflex, and the spinal accessory nerve all exit the skull through the jugular foramen. These nerves are most frequently affected if the jugular foramen is compressed. As a result, the patient’s gag reflex is impaired.
The vestibulocochlear nerve is primarily responsible for hearing. The trigeminal nerve provides sensation in the face. The facial nerve innervates the muscles of face expression (including those responsible for closing the eye). Tongue motions are controlled mostly by the hypoglossal nerve.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 30
Incorrect
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As a response to low blood pressure, the baroreceptor reflex will facilitate vasoconstriction by activating which receptor?
Your Answer: Beta1
Correct Answer: Alpha1
Explanation:The rate of baroreceptor firing slows down when blood pressure falls too low. This causes an increase in sympathetic stimulation of the heart, resulting in an increase in cardiac output. It also causes vasoconstriction by activating alpha 1 receptors in smooth muscle, which causes sympathetic stimulation of peripheral vessels.
Alpha2 receptors can be found in both the brain and the peripheral nervous system. They control sympathetic outflow in the brain stem.
Beta1 receptors, which are found on the cell membrane of cardiac muscle cells, stimulate heart rate and myocardial contractility. The smooth muscle cell membrane contains beta2 receptors, which promote smooth muscle relaxation in the lungs causing bronchodilation, GI tract, and peripheral blood vessels.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 31
Correct
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The triage nurse asks if you will prescribe a dose of codeine phosphate for a patient who is in a lot of pain. You discover that you are unable to prescribe it due to a contra-indication after evaluating the patient.
The use of codeine phosphate is contraindicated in which of the following situations?Your Answer: Age under 12 years
Explanation:Codeine phosphate is a mild opiate that can be used to treat mild to moderate pain when other pain relievers like paracetamol or ibuprofen have failed. It can also be used to treat diarrhoea and coughs that are dry or painful.
The use of all opioids is contraindicated for the following reasons:
Respiratory depression (acute)
Patients who are comatose
Head injury (opioid analgesics impair pupillary responses, which are crucial for neurological evaluation)
Intracranial pressure has risen (opioid analgesics interfere with pupillary responses vital for neurological assessment)
There’s a chance you’ll get paralytic ileus.The use of codeine phosphate is contraindicated in the following situations:
Because of the significant risk of respiratory side effects in children under the age of 12, it is not recommended for children under the age of 12.Patients of any age who have been identified as ultra-rapid codeine metabolizers (CYP2D6 ultra-rapid metabolizers)
Because codeine can pass through breast milk to the baby and because mothers’ ability to metabolise codeine varies greatly, it is especially dangerous in breastfeeding mothers.
If other painkillers, such as paracetamol or ibuprofen, fail to relieve acute moderate pain in children over the age of 12, codeine should be used. In children with obstructive sleep apnoea who received codeine after tonsillectomy or adenoidectomy, a significant risk of serious and life-threatening adverse reactions has been identified.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 32
Incorrect
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For the treatment of his atrial fibrillation, a 67-year-old man is about to begin taking warfarin. He also takes a number of other medications.
Which of the following medications will prevent warfarin from working?Your Answer: Ciprofloxacin
Correct Answer: Phenytoin
Explanation:Many medications, including warfarin, require cytochrome P450 enzymes for their metabolism. When co-prescribing cytochrome p450 enzyme inducers and inhibitors with warfarin, it’s critical to be cautious.
Inhibitors of the cytochrome p450 enzyme inhibit the effects of warfarin, resulting in a lower INR. To remember the most commonly encountered cytochrome p450 enzyme inducers, use the mnemonic PC BRASS:
P– Phenytoin
C– Carbamazepine
B– Barbiturates
R– Rifampicin
A– Alcohol (chronic ingestion)
S– Sulphonylureas
S– Smoking -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 33
Incorrect
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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 membrane surface area increases.
Correct 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 34
Correct
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You examine a child who has been admitted to the paediatric emergency department with a flu-like illness. His parents tell you that he was born with an inborn defect of steroid metabolism and that he was treated for it with hormone replacement therapy.
Which of the following is classified as a steroid hormone?
Your Answer: Aldosterone
Explanation:Hormones can be classified into three categories depending on their chemical composition: amines, peptides (and proteins), and steroids. Amines are made up of single amino acids (for example, tyrosine), peptide hormones are made up of peptides (or proteins), and steroid hormones are made up of cholesterol.
The table below lists some prominent instances of each of these three hormone classes:1. Peptide hormone:
Adrenocorticotropic hormone (ACTH)
Prolactin
Vasopressin
Oxytocin
Glucagon
Insulin
Somatostatin
Cholecystokinin2. Amine hormone:
Adrenaline (epinephrine)
Noradrenaline (norepinephrine)
Dopamine3. Steroid hormone:
Mineralocorticoids (e.g. aldosterone)
Glucocorticoids (e.g. cortisol)
Progestogens
Androgens
Oestrogens -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 35
Incorrect
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A 32-year-old man is dehydrated as he presents with severe vomiting and diarrhoea. He urgently requires resuscitation with intravenous fluid administration. He is also administered metoclopramide.
Which of the following is the true mechanism of action of metoclopramide?Your Answer: 5-HT3 receptor agonism
Correct Answer: Dopamine receptor antagonism
Explanation:Metoclopramide is used to treat nausea and vomiting. It works by blocking the central and peripheral D2 (dopamine 2) receptors in the medullary chemoreceptor trigger zone in the vomiting centre (area postrema). It decreases the sensitivity of the visceral sensory nerves that transmit from the GI system to the vomiting centre. Blockade of inhibitory dopamine receptors in the GI tract may allow stimulatory actions of ACh at muscarinic synapses to predominate.
At high doses, metoclopramide also blocks type-2 serotonin receptors though the effect is much weaker.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 36
Incorrect
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A 65-year-old man presents with cough and shortness of breath. His sputum is rusty in colour and is suffering from a fever. Upon examination, it was noted that he has crackles in the right upper lobe. A chest X-ray showed the presence of a right upper lobe cavitation.
Among the following microorganisms, which is considered to be mostly associated with a cavitating upper lobe pneumonia?Your Answer: Pneumocystis jiroveci
Correct Answer: Klebsiella pneumoniae
Explanation:Klebsiella pneumoniae is among the most common Gram-negative bacteria encountered by physicians worldwide and accounts for 0.5-5.0% of all cases of pneumonia. This organism can cause extensive pulmonary necrosis and frequent cavitation.
It is one of the causes that could be suspected when there is cavitatory pneumonia with or without a bulging fissure sign. Often, there can be extensive lobar opacification with air bronchograms.
A helpful feature which may help to distinguish from pneumococcal pneumonia is that Klebsiella pneumoniae develops cavitation in 30-50% of cases (in comparison, cavitation is rare in pneumococcal pneumonia). This occurs early and progresses quickly.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 37
Incorrect
-
During quiet respiration, position of the right oblique fissure can be marked by a line drawn on the thoracic wall that:
Your Answer: Begins at the spinous process of T3, crosses the fourth intercostal space laterally and follows the contour of rib 6 anteriorly.
Correct Answer: Begins at the spinous process of T4, crosses the fifth intercostal space laterally and follows the contour of rib 6 anteriorly.
Explanation:During quiet respiration, the approximate position of the right oblique fissure can be marked by a line on the thoracic wall that begins at the spinous process of vertebra T4, crosses the fifth intercostal space laterally and then follows the contour of rib 6 anteriorly.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 38
Incorrect
-
One of the benefits of wound healing through first intention is:
Your Answer: Reduced risk of foreign body in wound
Correct Answer: Minimisation of scar tissue formation
Explanation:Primary wound healing, or healing by first intention, occurs within hours of repairing a full-thickness surgical incision. This surgical insult results in the mortality of a minimal number of cellular constituents. Healing by first intention can occur when the wound edges are opposed, the wound is clean and uninfected and there is minimal loss of cells and tissue i.e. surgical incision wound. The wound margins are joined by fibrin deposition, which is subsequently replaced by collagen and covered by epidermal growth.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 39
Incorrect
-
A dermatological examination of a patient who has presented with a lump shows a collection of boils clustered together.
Which one of these best describes the lump you have found on examination?Your Answer: Furuncle
Correct Answer: Carbuncle
Explanation: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 vesicle is a visible collection of clear fluid measuring less 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 40
Incorrect
-
A 35-year-old man is feeling unwell following his return from a business trip. He is diagnosed with a vector transmitted disease.
Which of these organisms is commonly spread by vector-borne transmission?Your Answer: Bordatella pertussis
Correct Answer: Borrelia burgdorferi
Explanation:Borrelia burgdorferiis, primarily spread by ticks and lice, is a zoonotic, vector-borne organism that causes Lyme disease.
Neisseria meningitidis and Bordetella pertussis are droplet borne infections (airborne particle > 5 µm)
Vibrio cholerae and Ascaris lumbricoides are spread by the faeco-oral route
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 41
Incorrect
-
Which of the following is NOT a common side effect of diazepam:
Your Answer: Ataxia
Correct Answer: Bradycardia
Explanation:Adverse effects include:
Drowsiness and lightheadedness
Confusion and ataxia (especially in the elderly), amnesia, muscle weakness
Headache, vertigo, tremor, dysarthria, hypotension, decreased libido, erectile dysfunction, gynaecomastia, urinary retention
Paradoxical effects such as talkativeness, excitement, irritability, aggression, anti-social behaviour, and suicidal ideation
Withdrawal symptoms, for example anxiety, depression, anorexia, impaired concentration, insomnia, abdominal cramps, palpitations, tremor, tinnitus and perceptual disturbances
Tolerance and dependence (people who use benzodiazepines longer term can develop tolerance and eventual dependence) -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 42
Correct
-
A 53-year-old man arrives at the emergency department complaining of visual impairment in his right eye. On examination, you notice that neither his right nor left pupil constricts when you shine a light in his right eye. When you flash a light in his left eye, the pupils of both his left and right eyes constrict. Which of the following nerves is the most likely to be affected:
Your Answer: Optic nerve
Explanation:In full optic nerve palsy, the afferent pupillary light reflex is lost. Because the afferent optic nerve does not sense light flashed in the afflicted eye, the ipsilateral direct and contralateral consensual reflexes are gone. However, the contralateral direct and ipsilateral consensual reflexes are intact because the efferent oculomotor nerve is normal.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 43
Correct
-
A 23-year-old has a known diagnosis of HIV. Blood is sent to the laboratory for tests.
AIDS be diagnosed at a CD4 counts below?Your Answer: 200 cells/mm 3
Explanation:A normal CD4 count ranges from 500-1000 cells/mm3.
At CD4 count of less than 350 cells/mm3 treatment with anti-retroviral therapy should be considered.
At a CD4 count of >200 cells/mm3 AIDS is diagnosed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 44
Correct
-
ACE inhibitors are indicated for all of the following EXCEPT for:
Your Answer: Angina
Explanation:ACE inhibitors have many uses and are generally well tolerated. They are indicated for:
- Heart failure
- Hypertension
- Diabetic nephropathy
- Secondary prevention of cardiovascular events
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 45
Incorrect
-
Regarding Clostridium species, which of the following statements is INCORRECT:
Your Answer: They are Gram-positive.
Correct Answer: They are facultative anaerobes.
Explanation:Clostridium spp. are obligatory anaerobic spore-forming Gram-positive bacilli. Toxin production is the main pathogenicity mechanism.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 46
Incorrect
-
Which of the following local anaesthetics has the longest duration of action:
Your Answer: Lidocaine
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 47
Incorrect
-
Which of the following muscles laterally rotates the hip?
Your Answer: Gluteus medius
Correct Answer: Gluteus maximus
Explanation:External (lateral) rotation at the hip joint is produced by the gluteus maximus together with a group of 6 small muscles (lateral rotators): piriformis, obturator internus, superior and inferior gemelli, quadratus femoris and obturator externus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 48
Correct
-
Metabolic hyperaemia harmonizes local blood flow with local O2 demand. If there is an increase in metabolic rate, the production of vasoactive metabolites increases. These metabolites act locally on the surrounding arterioles, causes vasodilation and an increase blood supply.
Which of these metabolites is the most potent vasodilator in skeletal muscle?Your Answer: K +
Explanation:Hyperaemia is the process where the body adjusts blood flow to meet the metabolic needs of different tissues in health and disease. Vasoactive mediators that take part in this process include K+, adenosine, CO2, H+, phosphates and H2O2. Although the mechanism is not clear, all these mediators likely contribute to some extent at different points.
Specific organs are more sensitive to specific metabolites:
K+ and adenosine are the most potent vasodilators in skeletal musclesCO2 and K+ are the most potent vasodilators in cerebral circulation.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 49
Incorrect
-
The transport of oxygen from maternal to fetal circulation is made possible by fetal haemoglobin. Which of the statements about fetal haemoglobin (HbF) is also correct?
Your Answer: It is composed of two alpha and two beta subunits
Correct Answer: The oxygen dissociation curve for foetal haemoglobin is shifted to the left of that of adult haemoglobin
Explanation:Fetal haemoglobin is the most common type of haemoglobin found in the foetus during pregnancy. It transports oxygen from the maternal circulation to the fetal circulation. It can easily bind to oxygen from the maternal circulation because it has a high affinity for oxygen. From 10 to 12 weeks of pregnancy to the first six months after birth, the erythroid precursor cells produce fetal haemoglobin. In comparison to adult haemoglobin, fetal haemoglobin has two alpha and two gamma subunits, whereas adult haemoglobin has two alpha and two beta subunits in its major form.
And, unlike adult haemoglobin, the oxygen dissociation curve of fetal haemoglobin is left-shifted. Myoglobin is an oxygen storage molecule with a very high affinity for oxygen. Only when the partial pressure of oxygen is exceeded does it release oxygen.
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This question is part of the following fields:
- Physiology
- Respiratory Physiology
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Question 50
Incorrect
-
A 50-year-old man managed by the renal team for stage 4 chronic kidney disease which appears to be deteriorating presents with a history of shortness of breath and ankle oedema. His most recent blood tests shows low calcium levels.
Which of these increases the renal reabsorption of calcium?Your Answer: Renin
Correct Answer: Parathyroid hormone
Explanation:Parathyroid hormone (PTH), a polypeptide containing 84 amino acids, is the principal hormone that controls free calcium in the body.
Its main actions are:
Increases osteoclastic activity
Increases plasma calcium concentration
Decreases renal phosphate reabsorption
Decreases plasma phosphate concentration
Increases renal tubular reabsorption of calcium
Increases calcium and phosphate absorption in the small intestine
Increases renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 51
Incorrect
-
Regarding skeletal muscle, which of the following best describes the Z-line:
Your Answer: A line dividing myofibrils into myofilaments
Correct Answer: A line dividing muscle fibres into sarcomeres
Explanation:Each muscle fibre is divided at regular intervals along its length into sarcomeres separated by Z-lines. The sarcomere is the functional unit of the muscle.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 52
Incorrect
-
An ambulance transports a 23-year-old woman who has taken a witnessed overdose of her mother's diazepam tablets. She has no significant medical history and does not take any medications on a regular basis.
In this case, what is the SINGLE MOST APPROPRIATE FIRST DRUG TREATMENT?Your Answer: Flumazenil IV 20 μg
Correct Answer: Flumazenil IV 200 μg
Explanation:Flumazenil is a benzodiazepine antagonist that can be helpful in some overdose situations. It works quickly (in less than a minute), but the effects are fleeting, lasting less than an hour. The dose is 200 micrograms every 1-2 minutes with a maximum dose of 3 milligrams per hour.
Flumazenil should be avoided by patients who are addicted to benzodiazepines or who take tricyclic antidepressants because it can cause withdrawal symptoms. It can cause seizures or cardiac arrest in these situations.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 53
Correct
-
Which of the following hormones regulates Na+reabsorption in the proximal tubule:
Your Answer: Angiotensin II
Explanation:Angiotensin II increases Na+reabsorption from the proximal tubule (by activating Na+/H+antiporters).
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This question is part of the following fields:
- Physiology
- Renal
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Question 54
Incorrect
-
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 55
Incorrect
-
A 36-year-old woman is 22-weeks pregnant and is investigated for a possible thyroid disorder. When her total thyroid hormone levels does not correlate with her thyrometabolic status, her thyroid-binding globulin levels are checked.
What percentage of circulating thyroid hormones is bound to thyroid-binding globulin?Your Answer: 99%
Correct Answer: 70%
Explanation:Only a very small fraction of the thyroid hormones circulating in the blood are free. The majority is bound to transport proteins. Only the free thyroid hormones are biologically active, and measurement of total thyroid hormone levels can be misleading.
The relative percentages of bound and unbound thyroid hormones are:
Bound to thyroid-binding globulin -70%
Bound to albumin -15-20%
Bound to transthyretin -10-15%
Free T3 -0.3%
Free T4 -0.03% -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 56
Incorrect
-
A 28-year-old asthmatic patient is seen in the Emergency Department following an acute exacerbation. His symptoms start to improve when your consultant gives him a high dose of IV aminophylline.
Which of the following is correct mechanism of action of aminophylline ?Your Answer: Beta 2 -receptor antagonism
Correct Answer: Inhibition of phosphodiesterase
Explanation:Aminophylline has the following properties:
Phosphodiesterase inhibitor that increases intracellular cAMP and relaxes smooth muscle in the bronchial airways and pulmonary blood vessels.
Mast cell stabilization is achieved by using a non-selective adenosine receptor antagonist. -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 57
Correct
-
Lidocaine's antiarrhythmic mode of action is as follows:
Your Answer: Blocks inactivated Na+ channels
Explanation:Lidocaine is a class 1B antidysrhythmic; combines with fast Na channels and thereby inhibits recovery after repolarization, resulting in decreasing myocardial excitability and conduction velocity. However, in ischaemic areas, where anoxia causes depolarisation and arrhythmogenic activity, many Na+ channels are inactivated and therefore susceptible to lidocaine.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 58
Incorrect
-
Regarding the trachea, which of the following statements is INCORRECT:
Your Answer: The trachea begins at vertebral level C6.
Correct Answer: A cricothyrotomy involves making an opening in the neck inferior to the cricoid cartilage.
Explanation:A cricothyrotomy involves making an opening in the median cricothyroid ligament (the medial part of the cricothyroid membrane), between the cricoid cartilage below and the thyroid cartilage above.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 59
Incorrect
-
Which of the following nerves provides sensory innervation to the anteromedial and anterosuperior aspects of the external ear?
Your Answer: Great auricular nerve
Correct Answer: Auriculotemporal nerve
Explanation:Sensory innervation to the external ear is supplied by both cranial and spinal nerves. Branches of the trigeminal, facial, and vagus nerves (CN V, VII, X) are the cranial nerve components, while the lesser occipital (C2, C3) and greater auricular (C2, C3) nerves are the spinal nerve components involved. The lateral surface of the tympanic membrane, the external auditory canal, and the external acoustic meatus are all innervated by nervus intermedius (a branch of CN VII), the auriculotemporal nerve (CN V3), and the auricular branch of the vagus nerve. The concha receives split innervation from nervus intermedius, the auricular branch of the vagus nerve, and the greater auricular (spinal) nerve. Beyond the concha, the anteromedial and anterosuperior parts of the pinna are innervated by the auriculotemporal nerve, and a portion of the lateral helix by the lesser occipital nerve. The greater auricular nerve provides innervation to the area of the pinna inferolateral to the lobule.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 60
Incorrect
-
Depression of the eyeball is primarily produced by which of the following muscles:
Your Answer: Inferior rectus and inferior oblique
Correct Answer: Inferior rectus and superior oblique
Explanation:Depression of the eyeball is produced by the inferior rectus and the superior oblique muscles.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 61
Incorrect
-
Which of the following is most likely affected in De Quervain's tenosynovitis?
Your Answer: Extensor carpi radialis brevis
Correct Answer: Extensor pollicis brevis
Explanation:De Quervain tenosynovitis is named after the Swiss surgeon, Fritz de Quervain, who first described it in 1895. It is a condition which involves tendon entrapment affecting the first dorsal compartment of the wrist. With this condition thickening of the tendon sheaths around the abductor pollicis longus and extensor pollicis brevis develops where the tendons pass in through the fibro-osseous tunnel located along the radial styloid at the distal wrist. Pain is exacerbated by thumb movement and radial and ulnar deviation of the wrist.
The estimated prevalence of de Quervain tenosynovitis is about 0.5% in men and 1.3% in women with peak prevalence among those in their forties and fifties. It may be seen more commonly in individuals with a history of medial or lateral epicondylitis. Bilateral involvement is often reported in new mothers or child care providers in whom spontaneous resolution typically occurs once lifting of the child is less frequent.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 62
Correct
-
The Frank-Starling curve is shifted downhill in heart failure due to which of the following?
Your Answer: Decrease in contractility
Explanation:The Frank–Starling mechanism states that the left ventricle can increase its force of contraction and hence stroke volume in response to increases in venous return and thus preload.
Changes in afterload or inotropy cause the Frank–Starling curve to rise or fall. In heart failure, the Frank–Starling curve is shifted downward (flattened), requiring higher venous return and filling pressure to enhance contractility and stroke volume.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 63
Correct
-
Which of the following is required for vitamin B12 absorption:
Your Answer: Intrinsic factor
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 64
Incorrect
-
A 57-year-old male presents to the orthopaedic clinic complaining of pain and swelling in the left knee joint. On examination, the left knee is swollen, tender and erythematous. The patient is booked for joint aspiration, and a diagnosis of pseudogout is made following the aspiration.
Which types of crystals would be seen in the joint aspirate to lead to this diagnosis?Your Answer: Negatively birefringent brick-shaped crystals
Correct Answer: Positively birefringent brick-shaped crystals
Explanation:Gout and pseudogout are both characterised by crystal deposition in the affected joints. The deposition of urate crystals causes gout, while calcium pyrophosphate crystals cause pseudogout. The crystals can be distinguished microscopically because urate crystals are negatively birefringent needle-shaped crystals, whilst calcium pyrophosphate crystals are positively birefringent brick-shaped crystals.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 65
Incorrect
-
Which of the following causes increased aldosterone secretion:
Your Answer: Hypokalaemia
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 66
Correct
-
A 58-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.
Which of the following is the patient's preferred drug treatment?Your Answer: Nicardipine
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.
Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.
Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.
The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.
An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 67
Incorrect
-
Which of the following is most likely to cause a homonymous hemianopia:
Your Answer: Optic neuritis
Correct Answer: Posterior cerebral artery stroke
Explanation:A posterior cerebral stroke will most likely result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 68
Incorrect
-
A 25-year-old female arrives at the emergency room with a severe case of asthma. When she doesn't seem to be improving after initial treatment, you decide to start an aminophylline infusion.
From the options below, which is Aminophylline's main mechanism of action?Your Answer: Beta receptor agonism
Correct Answer: Phosphodiesterase inhibition
Explanation:Theophylline and Ethylenediamine are combined in a 2:1 ratio to form Aminophylline. Its solubility is improved by the addition of Ethylenediamine. It has a lower potency and a shorter duration of action than Theophylline.
It is used to treat the following conditions:
Heart failure
It is used to treat the following conditions:
COPD
BradycardiasAminophylline has the following properties:
Phosphodiesterase inhibitor that increases intracellular cAMP and relaxes smooth muscle in the bronchial airways and pulmonary blood vessels.
Mast cell stabilization is achieved by using a non-selective adenosine receptor antagonist.
It has slight positive inotropic and chronotropic effects, increasing cardiac output and decreasing systemic vascular resistance, lowering arterial blood pressure. It has been used historically in the treatment of refractory heart failure and is indicated by the current ALS guidelines as a substitute treatment for bradycardia.The daily oral dose for adults is 900 mg, divided into 2-3 doses. For severe asthma or COPD, a loading dosage of 5 mg/kg over 10-20 minutes is given, followed by a continuous infusion of 0.5 mg/kg/hour. The therapeutic range is small (10-20 microgram/ml), hence assessments of aminophylline plasma concentrations are useful during long-term treatment.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 69
Incorrect
-
Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer: Both ventilation and perfusion decrease towards the base of the lung.
Correct Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 70
Incorrect
-
A patient presents with severe vomiting. They take a maintenance dose of 12.5 mg of prednisolone daily for their COPD. They are unable to swallow or keep down tablets at present, and you plan on converting them to IV hydrocortisone.
What dose of hydrocortisone is equivalent to this dose of prednisolone? Select ONE answer only.Your Answer: 25 mg
Correct Answer: 50 mg
Explanation:Prednisolone is four times more potent than hydrocortisone, and therefore, a dose of 12.5 mg would be equivalent to 50 mg of hydrocortisone.
The following table summarises the relative potency of the main corticosteroids compared with hydrocortisone:
Corticosteroid
Potency relative to hydrocortisone
Prednisolone
4 times more potent
Triamcinolone
5 times more potent
Methylprednisolone
5 times more potent
Dexamethasone
25 times more potent -
This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 71
Incorrect
-
A patient presents with an acute severe asthma attack. Following a poor response to his initial salbutamol nebuliser, you administer a further nebuliser that this time also contains ipratropium bromide.
After what time period would you expect the maximum effect of the ipratropium bromide to occur? Select ONE answer only.Your Answer: 10-15 minutes
Correct Answer: 30 -60 minutes
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.
The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.
The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.
The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma) -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 72
Correct
-
A 39-year-old man with a long history of depression presents after intentionally overdoing his heart medication. Verapamil immediate-release 240 mg is the tablet he takes for this condition, he says. He took the pills about 30 minutes ago, but his wife discovered him right away and rushed him to the emergency room.
At the moment, he is completely symptom-free. When it comes to this type of overdose, how long does it usually take for symptoms to appear?Your Answer: 1-2 hours
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.
>10 tablets of verapamil (160 mg or 240 mg immediate or sustained-release capsules) or diltiazem can cause serious toxicity (180 mg, 240 mg or 360 mg immediate or sustained-release capsules)
In children, 1-2 tablets of verapamil or diltiazem (immediate or sustained-release)
Symptoms usually appear within 1-2 hours of ingestion with standard preparations. However, with slow-release preparations, significant toxicity may take 12-16 hours to manifest, with peak effects occurring after 24 hours.
The following are the main clinical features of calcium-channel blocker overdose:
Nausea and vomiting
Hypotension
Bradycardia and first-degree heart block
Myocardial ischaemia and stroke
Renal failure
Pulmonary oedema
HyperglycaemiaThe following are some of the most important bedside investigations to conduct:
Blood glucose
ECG
Arterial blood gas
Other investigations that can be helpful include
Urea & electrolytes
Chest X-ray (pulmonary oedema)
Echocardiography -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 73
Correct
-
Which of the following corticosteroids has the most potent mineralocorticoid effect:
Your Answer: Fludrocortisone
Explanation:Fludrocortisone has the most potent mineralocorticosteroid activity, making it ideal for mineralocorticoid replacement in adrenal insufficiency.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 74
Correct
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A 30 year old man presents to ED after a road traffic accident. Free intraperitoneal fluid is found on FAST (Focussed assessment for sonography in trauma) done in the supine position.
Which of these is most likely to be affected?
Your Answer: Hepatorenal recess
Explanation:Fluid accumulates most often in the hepatorenal pouch (of Morrison) in a supine patient. The hepatorenal pouch is located behind the liver and anterior to the right kidney and is the lowest space in the peritoneal cavity in the supine position.
Although the vesicouterine and rectouterine spaces are also potential spaces for fluid accumulation, fluid accumulation in them occur in the erect position.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 75
Incorrect
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1-alpha-hydroxylase is a cytochrome p450 enzyme that is involved in the production of vitamin D's hormonally active metabolite.
Which of the following promotes the activity of 1-alpha-hydroxylase?Your Answer: Growth hormone
Correct Answer: Parathyroid hormone
Explanation:1-alpha-hydroxylase converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol in the kidney.
The key regulatory point in the formation of 1,25-dihydroxycholecalciferol is 1-alpha-hydroxylase, which is promoted by parathyroid hormone or hypophosphatemia.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 76
Incorrect
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A patient is referred to the Medicine Department for complaints of unilateral hearing loss, tinnitus and facial numbness. Upon further investigation, an acoustic neuroma is given as the final diagnosis.
Which of the following nerves is least likely to be affected in acoustic neuroma?Your Answer: Vestibulocochlear nerve
Correct Answer: Trochlear nerve
Explanation:Acoustic neuroma is also called vestibular schwannoma (VS), acoustic neuroma, vestibular neuroma or acoustic neurofibroma. These are tumours that evolve from the Schwann cell sheath and can be either intracranial or extra-axial. They usually occur adjacent to the cochlear and vestibular nerves and most often arise from the inferior division of the latter. Anatomically, acoustic neuroma tends to occupy the cerebellopontine angle. About 5-10% of cerebellopontine angle (CPA) tumours are meningiomas and may occur elsewhere in the brain. Bilateral acoustic neuromas tend to be exclusively found in individuals with type 2 neurofibromatosis.
The following nerves may be affected due to nerve compression:
Facial nerve: usually minimal with late presentation except for very large tumours. Depending on the degree of engagement of the nerve, the symptoms may include twitching, increased lacrimation and facial weakness.
Trigeminal Nerve: paraesthesia in the trigeminal distribution, tingling of the tongue, impairment of the corneal reflex, and less commonly pain which may mimic typical trigeminal neuralgia.
Glossopharyngeal and Vagus nerves: palatal paresis, hoarseness of voice and dysphagia
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 77
Incorrect
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The pathophysiology of Addison's disease is as follows:
Your Answer: Chronic excess cortisol secretion
Correct Answer: Adrenocortical insufficiency
Explanation:Primary adrenal insufficiency, also known as Addison’s disease, occurs when the adrenal glands cannot produce an adequate amount of hormones despite a normal or increased corticotropin (ACTH) level.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 78
Incorrect
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Amoxicillin is used first line for all of the following infections EXCEPT for:
Your Answer: Infective exacerbation of chronic bronchitis
Correct Answer: Cellulitis
Explanation:Amoxicillin is used first line for low to moderate severity community acquired pneumonia, exacerbations of chronic bronchitis, for acute otitis media, for acute sinusitis, for oral infections/dental abscess, for Listeria meningitis (in combination with another antibiotic), for infective endocarditis (in combination with another antibiotic) and for H. Pylori eradication (in combination with metronidazole/clarithromycin and a PPI). Flucloxacillin is used first line for acute cellulitis.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 79
Incorrect
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Which of the following is most true of the sinoatrial node:
Your Answer: It is located between the right atrium and ventricle near the atrial septum.
Correct Answer: Frequency of depolarisation is increased by sympathetic stimulation.
Explanation:Cardiac myocyte contraction is not dependent on an external nerve supply but instead the heart generates its own rhythm, demonstrating inherent rhythmicity. The heartbeat is initiated by spontaneous depolarisation of the sinoatrial node (SAN), a region of specialised myocytes in the right atrium close to the coronary sinus, at a rate of 100-110 beats/min. This intrinsic rhythm is primarily influenced by autonomic nerves, with vagal influences being dominant over sympathetic influences at rest. This vagal tone reduces the resting heart rate down to 60-80 beats/min. To increase heart rate, the autonomic nervous system increases sympathetic outflow to the SAN, with concurrent inhibition of vagal tone. These changes mean the pacemaker potential more rapidly reaches the threshold for action potential generation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 80
Incorrect
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A suicidal patient had lacerated his wrist, which resulted in an ulnar nerve injury. Which of the following will confirm the presence of an ulnar nerve injury?
Your Answer: Loss of flexion of the index and ring fingers
Correct Answer: Claw hand appearance
Explanation:An ulnar injury may result in abnormal sensations in the little finger and ring finger, usually on the palm side, weakness, and loss of coordination of the fingers.
A claw like deformity of the hand and wrist is present. Pain, numbness, decreased sensation, tingling, or burning sensation in the areas controlled by the nerve are also possible.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 81
Incorrect
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You examine a 34-year-old lady with symptoms that are consistent with acute sinusitis. You're thinking about giving her doxycycline for treatment.
What is doxycycline's mechanism of action?Your Answer: Anti-metabolic activity
Correct Answer: Inhibition of protein synthesis
Explanation:Doxycycline and other tetracycline antibiotics attach to the 30S subunit of the bacterial ribosome, preventing aminoacyl-tRNA binding and so protein synthesis beginning.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 82
Incorrect
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Regarding dermatophytes, which of the following statement is CORRECT:
Your Answer: Spread is via inhalation of spores.
Correct Answer: Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings.
Explanation:Diagnosis is made from microscopy and culture of skin scrapings, hair samples or nail clippings depending on the site of infection. The lesions of ringworm typically have a dark outer ring with a pale centre. Tinea capitis is ringworm affecting the head and scalp. Spread is via direct skin contact. Treatment is usually topical, oral antifungals are reserved for refractory infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 83
Incorrect
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Which of the following clinical features is most suggestive of a lesion of the temporal lobe:
Your Answer: Expressive dysphasia
Correct Answer: Receptive dysphasia
Explanation:Damage to the Wernicke’s speech area in the temporal lobe can result in a receptive dysphasia. Hemispatial neglect is most likely to occur in a lesion of the parietal lobe. Homonymous hemianopia is most likely to occur in a lesion of the occipital lobe. Expressive dysphasia is most likely to occur in a lesion of the Broca speech area in the frontal lobe. Conjugate eye deviation towards the side of the lesion is most likely to occur in a lesion of the frontal lobe.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 84
Incorrect
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The least likely feature of anaemia is:
Your Answer: Flow murmurs
Correct Answer: Narrow pulse pressure
Explanation:Non-specific signs of anaemia include:
1. pallor of mucous membranes or nail beds (if Hb < 90 g/L),
2. tachycardia
3. bounding pulse
4. wide pulse pressure
5. flow murmurs
6. cardiomegaly
7. signs of congestive cardiac failure (in severe cases) -
This question is part of the following fields:
- Haematology
- Pathology
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Question 85
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 86
Incorrect
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Identify the type of graph described below:
This graph is a scatter plot of the effect estimates from individual studies against some measure of each study's size or precision.
Your Answer: Kaplan-Meier plot
Correct Answer: Funnel plot
Explanation:A funnel plot is a scatter plot of the effect estimates from individual studies against some measure of each study’s size or precision. The standard error of the effect estimate is often chosen as the measure of study size and plotted on the vertical axis with a reversed scale that places the larger, most powerful studies towards the top. The effect estimates from smaller studies should scatter more widely at the bottom, with the spread narrowing among larger studies. In the absence of bias and between study heterogeneity, the scatter will be due to sampling variation alone and the plot will resemble a symmetrical inverted funnel. A triangle centred on a fixed effect summary estimate and extending 1.96 standard errors either side will include about 95% of studies if no bias is present and the fixed effect assumption (that the true treatment effect is the same in each study) is valid.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 87
Incorrect
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Regarding diuretics, which of the following statements is CORRECT:
Your Answer: Loop diuretics act on the thin descending limb.
Correct Answer: Carbonic anhydrase inhibitors have their effect by inhibiting bicarbonate reabsorption.
Explanation:Carbonic anhydrase inhibitors e.g. acetazolamide block the reaction of carbon dioxide and water and so prevent Na+/H+exchange and bicarbonate reabsorption. The increased bicarbonate levels in the filtrate oppose water reabsorption. Proximal tubule sodium reabsorption is also reduced because it is partly dependent on bicarbonate reabsorption.
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This question is part of the following fields:
- Physiology
- Renal
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Question 88
Incorrect
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Which of the following does NOT predispose to digoxin toxicity in a patient taking digoxin:
Your Answer: Hypomagnesaemia
Correct Answer: Hyponatraemia
Explanation:Hypoxia, hypercalcaemia, hypokalaemia and hypomagnesaemia predispose to digoxin toxicity. Care should also be taken in the elderly who are particularly susceptible to digoxin toxicity. Hypokalaemia may be precipitated by use of diuretics. Although hyponatremia can result in the development of other pathological disturbances, it does not potentiate digoxin toxicity.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 89
Incorrect
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A 50-year-old woman has an anaphylactic reaction following accidental ingestion peanuts at a restaurant. She is a known hypertensive on atenolol 50 mg daily and BP is well controlled. She is also on amlodipine 5 mg daily. Two doses of IM adrenaline has been given without improvement.
Which medication may prove helpful in this patient?
Your Answer: Fresh frozen plasma
Correct Answer: IM Glucagon
Explanation:Resistant to the effects of adrenaline in anaphylaxis is seen in patients taking beta-blockers.
Glucagon can be used to overcome the effects of the beta-blockade if initial doses of adrenaline are unsuccessful in patients taking beta-blockers.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 90
Incorrect
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A 24-year-old student with red and painful right eye presents. Conjunctival erythema, mucopurulent discharge and lid crusting are seen on examination, and patient denies presence of itching of the eye. All his observations are normal, he has no fever and is otherwise well.
Which of these is the most likely causative organism?
Your Answer: Picornavirus
Correct Answer: Haemophilus influenzae
Explanation:The most frequent cause of red eye is conjunctivitis. It is caused by inflammation of the conjunctiva which can be infective or allergic and accounts for about 35% of all eye problems presenting to general practice.
Viral conjunctivitis is commonly caused by adenoviruses and it is the most common infectious conjunctivitis.
The common bacterial causes of conjunctivitis are Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus.
The clinical features of infective conjunctivitis include:
Acute onset of conjunctival erythema
Feeling ‘grittiness’, ‘foreign body’ or ‘burning’ sensation in the eye.
Watering and discharge which may cause transient blurring of visionThe discharge for viral conjunctivitis is less than that of bacterial conjunctivitis and usually watery.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 91
Incorrect
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Cardiac myocytes are connected to each other by which of the following:
Your Answer: Sarcolemma
Correct Answer: Intercalated discs
Explanation:Adjacent cardiac myocytes are connected to each other by intercalated discs. The intercalated discs provide both a structural attachment by ‘glueing’ cells together at desmosomes and an electrical contact made up of proteins called connexons, called a gap junction, which essentially creates a low-resistance pathway between cells.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 92
Correct
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Which of the following statements about lithium treatment is FALSE:
Your Answer: Concomitant treatment with NSAIDs decreases serum-lithium concentration.
Explanation:Lithium levels are raised by NSAIDs because renal clearance is reduced. Lithium is a small ion (74 Daltons) with no protein or tissue binding and is therefore amenable to haemodialysis. Lithium is freely distributed throughout total body water with a volume of distribution between 0.6 to 0.9 L/kg, although the volume may be smaller in the elderly, who have less lean body mass and less total body water. Steady-state serum levels are typically reached within five days at the usual oral dose of 1200 to 1800 mg/day. The half-life for lithium is approximately 18 hours in adults and 36 hours in the elderly.
Lithium is excreted almost entirely by the kidneys and is handled in a manner similar to sodium. Lithium is freely filtered but over 60 percent is then reabsorbed by the proximal tubules. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 93
Incorrect
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Regarding haemoglobin, which of the following statements is CORRECT:
Your Answer: Foetal haemoglobin remains the primary haemoglobin in infants up until about 1 year of age.
Correct Answer: In degradation of haemoglobin, the haem group is split from the haemoglobin and converted to biliverdin and ultimately to bilirubin.
Explanation:Haemoglobin is composed of four polypeptide globin chains each with its own iron containing haem molecule. Haem synthesis occurs largely in the mitochondria by a series of biochemical reactions commencing with the condensation of glycine and succinyl coenzyme A under the action of the key rate-limiting enzyme delta-aminolevulinic acid (ALA) synthase. The globin chains are synthesised by ribosomes in the cytosol. Haemoglobin synthesis only occurs in immature red blood cells.
There are three types of haemoglobin in normal adult blood: haemoglobin A, A2 and F:
– Normal adult haemoglobin (HbA) makes up about 96 – 98 % of total adult haemoglobin, and consists of two alpha (α) and two beta (β) globin chains.Â
– Haemoglobin A2 (HbA2), a normal variant of adult haemoglobin, makes up about 1.5 – 3.5 % of total adult haemoglobin and consists of two α and two delta (δ) globin chains.
– Foetal haemoglobin is the main Hb in the later two-thirds of foetal life and in the newborn until approximately 12 weeks of age. Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin.Â
Red cells are destroyed by macrophages in the liver and spleen after , 120 days. The haem group is split from the haemoglobin and converted to biliverdin and then bilirubin. The iron is conserved and recycled to plasma via transferrin or stored in macrophages as ferritin and haemosiderin. An increased rate of haemoglobin breakdown results in excess bilirubin and jaundice. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 94
Incorrect
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A patient presents with a rash for a dermatological examination. A flat circumscribed area of discoloured skin measuring 0.7 cm in diameter is seen on examination.
What is the best description of this rash that you have found on examination?
Your Answer: Papule
Correct Answer: Macule
Explanation:A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
A vesicle is a visible collection of clear fluid measuring less than 0.5 cm in diameter.
A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 95
Incorrect
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The syndrome of inappropriate antidiuresis due to excessive antidiuretic hormone (ADH) secretion is diagnosed in a male patient with a history of recurrent hyponatraemia.
Which of the following produces ADH?Your Answer: Anterior pituitary
Correct Answer: Hypothalamus
Explanation:Antidiuretic hormone (ADH), commonly known as vasopressin, is a peptide hormone that controls how much water the body retains.
It is produced in the magnocellular and parvocellular neurosecretory cells of the paraventricular nucleus and supraoptic nucleus in the hypothalamus from a prohormone precursor. It is subsequently carried to the posterior pituitary via axons and stored in vesicles.
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.Stretch receptors in the atrial walls and big veins detect a decrease in atrial pressure as a result of this (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.The main sites of action for ADH are:
The kidney is made up of two parts. ADH’s main job is to keep the extracellular fluid volume under control. It increases permeability to water by acting on the renal collecting ducts via V2 Receptors (via a camp-dependent mechanism). This leads to a decrease in urine production, an increase in blood volume, and an increase in arterial pressure as a result.Vascular system: Vasoconstriction is a secondary function of ADH. ADH causes vasoconstriction via binding to V1 Receptors on vascular smooth muscle (via the IP3 signal transduction pathway). An increase in arterial pressure occurs as a result of this.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 96
Incorrect
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Regarding the lumbar plexus, which of the following is a direct muscular branch?
Your Answer: Nerve to obturator internus
Correct Answer: Nerve to quadratus lumborum
Explanation:The lumbar plexus gives rise to several branches which supply various muscles and regions of the posterior abdominal wall and lower limb. These branches include the Iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral and obturator nerves.
In addition, the lumbar plexus gives off muscular branches from its roots, a branch to the lumbosacral trunk and occasionally an accessory obturator nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 97
Incorrect
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A 1-year-old male is brought to the paediatrician by his mother due to swelling of the right knee after a minor fall. On examination, the right knee is swollen, fluctuant and tender. Ultrasound-guided aspiration reveals a massive hemarthrosis. Family history shows that his older brother also has a bleeding disorder.
Which one of the following conditions does the patient most likely have?Your Answer: Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Correct Answer: Haemophilia A
Explanation:A diagnosis of Haemophilia is supported in this patient by the family history and the presence of hemarthrosis-both characteristics of Haemophilia. Haemophilia A is caused by Factor VIII deficiency, leading to impaired coagulation. This disease typically presents after six months when the child starts crawling.
Von Willebrand disease presents with nosebleeds and hematomas. Idiopathic thrombocytopenic purpura presents with bruises that resemble a rash.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency presents with haemolytic anaemia induced by specific drugs or foods.
Factor V Leiden mutation causes blood clotting rather than bleeding.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 98
Incorrect
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Which of the following increases the tendency for oedema to occur?
Your Answer: Venodilation
Correct Answer: Increased venous pressure
Explanation:When more fluid is filtered out of the capillaries than can be returned to the circulation by the lymphatics, oedema occurs. Changes that increase capillary hydrostatic pressure or decrease plasma oncotic pressure will increase filtration.
Arteriolar constriction reduces hydrostatic capillary pressure and transiently increase absorption of fluid.
Dehydration increases plasma protein concentration and therefore increases plasma oncotic pressure and absorption. Capillary hydrostatic pressure and filtration are increased when there is increased venous pressure. -
This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 99
Incorrect
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A 35-year-old lady has suffered a serious brain injury. Her uvula has deviated to the right, according to inspection. Which of the following nerves is likely to be affected?
Your Answer:
Correct Answer: Left vagus nerve
Explanation:When the vagus nerve is damaged, the soft palate is paralyzed and the uvula is shifted away from the affected side. The vagus nerve innervates the uvulae muscle, which forms the uvula’s core. If only one side is innervated, contraction of the active muscle will draw the uvula towards it.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 100
Incorrect
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Regarding the abductor pollicis longus, which of the following statements is true?
Your Answer:
Correct Answer: It extends the thumb at the carpometacarpal joint
Explanation:Abductor pollicis longus is a muscle found in the posterior compartment of the forearm. It is one of the five deep extensors in the forearm, along with the supinator, extensor pollicis brevis, extensor pollicis longus and extensor indicis.
Abductor pollicis longus is innervated by the posterior interosseous nerve (C7, C8), which is a continuation of the deep branch of the radial nerve. The radial nerve is a branch of the posterior cord of the brachial plexus.
Blood supply to the abductor pollicis longus muscle comes from the interosseous branches of the ulnar artery.
Acting alone or with abductor pollicis brevis, abductor pollicis longus pulls the thumb away from the palm. More specifically, it produces (mid-) extension and abduction of the thumb at the first metacarpophalangeal joint. This action is seen in activities such as bowling and shovelling.
Working together with the long and short extensors of the thumb, the muscle also helps to fully extend the thumb at the metacarpophalangeal joint. This action is important for loosening the hand grip, for example, when letting go of objects previously being held. Abductor pollicis longus also helps to abduct the hand (radial deviation) at the radiocarpal joint.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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SESSION STATS - PERFORMANCE PER SPECIALTY
