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Question 1
Correct
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What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 2
Correct
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The following are Gram-negative cocci:
Your Answer: Neisseria
Explanation:Gram-negative cocci include the four types that cause a sexually transmitted disease (Neisseria gonorrhoeae), a meningitis (Neisseria meningitidis), and respiratory symptoms (Moraxella catarrhalis, Haemophilus influenzae).
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 3
Correct
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A 30-year-old female presents with a 4-day history of diarrhoea and vomiting. She has been unable to keep fluids down for 4 days and has been treated with metoclopramide. She develops a dystonic reaction. What is the most appropriate treatment for this woman?
Your Answer: Benztropine
Explanation:Acute dystonic reactions (extrapyramidal symptoms) such as spasmodic torticollis, trismus, and oculogyric crises can occur following the administration of metoclopramide or stemetil and thus, neither is recommended for the treatment of nausea in young women.
Such reactions respond well to treatment with benztropine or procyclidine.
– Benztropine: It is an anticholinergic medication with significant CNS penetration. A single dose of benztropine 1 to 2 mg IV followed by 1 to 2 mg p.o twice a day for up to 7 days to prevent a recurrence. Subsequently, both the offending agent and those from the same group should be avoided.
– Alternatively, diphenhydramine can be used intravenously (up to a dose of 50mg) or intramuscularly followed by p.o therapy every 6 hours for 1 to 2 to prevent a recurrence.- Second-line therapy with IV benzodiazepines is reserved for those patients who do not respond to anticholinergics.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 4
Correct
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The interventricular septum is supplied anteriorly by the?
Your Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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A 50-year-old woman under treatment for manic-depressive psychosis presents in an unconscious state after an episode of seizure on the street. Her husband who accompanied her into the ER reported that they argued about 6-7 hours ago. On examination, she is found to be hypertonic with a GCS of 8, BP: 90/60 mmHg and a pulse of 105 bpm. Blood investigations revealed a lithium level of 3.2 mmol/L. She was intubated and ventilated. Which of the following is the most appropriate immediate management in this case?
Your Answer: N saline should be started iv
Explanation:- Normal saline (N saline) should be started IV: Intravenous normal saline is recommended to enhance renal excretion of lithium. Adequate hydration is crucial because lithium is primarily excreted by the kidneys, and maintaining good urine output can help reduce lithium levels.
- Dialysis: This is considered the most effective treatment for severe lithium toxicity, especially when serum levels are significantly elevated (typically >2.5 mmol/L) and the patient presents with severe symptoms such as seizures, altered mental status, or renal impairment. Given the patient’s lithium level of 3.2 mmol/L and her critical condition, dialysis is necessary to rapidly reduce lithium levels.
The other options are less appropriate or ineffective in this context:
- Gastric lavage should be considered: This is not typically recommended for lithium poisoning because lithium is rapidly absorbed and lavage is unlikely to be effective several hours post-ingestion.
- Activated charcoal is likely to be effective: Activated charcoal does not effectively bind lithium and is not recommended for lithium poisoning.
- 5% dextrose should be started IV: While maintaining hydration is important, normal saline is preferred over dextrose solutions in this context to promote renal excretion of lithium.
- Dialysis is not normally required unless levels are above 5 mmol/L: This statement is incorrect. Dialysis is often required at lower levels, particularly in cases of severe toxicity or if the patient is symptomatic, as seen in this case.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 6
Correct
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Medullary chemoreceptors
Your Answer: Monitor H+ concentration of the CSF
Explanation:Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 7
Correct
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Which of the following features is least commonly seen in Gitelman’s syndrome?
Your Answer: Hypertension
Explanation:Gitelman syndrome is an autosomal recessive kidney disorder characterized by hypokalaemia metabolic alkalosis with hypocalciuria, and hypomagnesemia. In contrast to patients with Gordon’s syndrome, those suffering from Gitelman’s syndrome are generally normotensive or hypotensive.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 8
Incorrect
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What is the structure of nucleosomes?
Your Answer: Strands of double strand DNA + telomeres
Correct Answer: Strands of double strand DNA + histones
Explanation:DNA is packed and condensed by binding to histone proteins. The double stranded DNA forms a complex with histone proteins which is called a nucleosome. There are 8 histone proteins contained in one core of nucleosome.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 9
Correct
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The brainstem contains which of the following structures?
Your Answer: The midbrain, pons and medulla
Explanation:Brain stem is the base of the brain that connects the brain to the spinal cord. It consists of the mid brain, pons and medulla oblongata.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 10
Correct
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A deficiency in Cyanocobalamin leads to which clinical deficiency syndrome?
Your Answer: Pernicious anaemia
Explanation:The main syndrome of vitamin B12 deficiency is pernicious anaemia. It is characterized by a triad of symptoms:Megaloblastic anaemiaGastrointestinal symptoms &Neurological symptoms
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 11
Correct
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Which of the following treatments would you advise for a young, 21 year old student who has ankylosing spondylitis and complains of worsening back pain and morning stiffness?
Your Answer: Oral NSAIDs
Explanation:NSAIDs are considered as the first line of treatment for managing pain and stiffness associated with ankylosing spondylitis. Other useful medications include TNF-alpha inhibitors. Other drugs like paracetamol, colchicine, and steroids are not routinely used. Bilateral total hip replacement might be indicated in advanced disease contrary to complicated spinal surgery.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 12
Correct
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Which of the following statements is true regarding pulsus alternans?
Your Answer: It is found in association with a third heart sound
Explanation:Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis. A pathological third heart sound is usually associated.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Correct
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Which of the following best describes the cardiac muscle?
Your Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Correct
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Which of the following conditions has no effect on cardiac output?
Your Answer: Sleep
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Incorrect
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Neurogenesis occurs throughout life in the following two areas:
Your Answer: Olfactory nerve and amygdala
Correct Answer: Hippocampus and striatum
Explanation:In humans, neurogenesis or new neurons are continually born during adulthood in two regions of the brain: The subgranular zone (SGZ), part of the dentate gyrus of the hippocampus and the striatum. In other species of mammals, adult-born neurons also appear in the olfactory bulb. In humans, however, few if any olfactory bulb neurons are generated after birth.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 16
Correct
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Carotid bodies...
Your Answer: Are located near the bifurcation of the carotid arteries bilaterally
Explanation:The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork (bifurcation) of the carotid artery (which runs along both sides of the throat).The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature. Carotid bodies trigger an action potential through the afferent fibers of the glossopharyngeal nerve,
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 17
Incorrect
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Transportation of proteins from the cell body to axonal terminals is known as:
Your Answer: Synaptic flow
Correct Answer: Axoplasmic flow
Explanation:Transportation of proteins from the cell body to axonal terminals is known as axoplasmic, axonal flow or Axonal transport.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 18
Correct
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Question 19
Correct
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What is the protective hexametric sequence at the ends of chromosomes called?
Your Answer: Telomere
Explanation:Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 20
Correct
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A 48-year-old male with a history of bipolar disorder presents with acute confusion. In-transit to hospital he had a generalized seizure which terminated spontaneously after around 30 seconds. On arrival to the emergency department, his GCS is 14/15 and he is noted to have a coarse tremor. Suspecting a diagnosis of lithium toxicity, intravenous access is obtained, a blood sample was drawn for investigations and a saline infusion is started. The blood investigations revealed:Lithium level: 4.2 mmol/lNa+: 136 mmol/lK+: 4.6 mmol/lUrea: 8.1 mmol/lCreatinine: 99 µmol/lBicarbonate: 18 mmol/lWhat is the most appropriate management for the patient?
Your Answer: Arrange haemodialysis
Explanation:The presentation of the patient is typical of chronic lithium toxicity (due to the presence of mainly neurological manifestations). Additional to the blood investigations mentioned, urine analysis, electrolyte levels, and renal function should also be performed. A low urine Anion gap and a low urine specific gravity are highly suggestive of lithium toxicity.ECG obtained in this patient is likely to show: nonspecific, diffuse ST segment depression with T wave inversion.Acute lithium toxicity presents with more GI manifestations while, the clinical features of chronic lithium toxicity are mainly neurological and can include:Coarse tremors (fine tremors are seen in therapeutic levels), hyperreflexia, acute confusion, seizures, and coma.The management of lithium toxicity is as follows:Immediate GI decontamination with gastric lavage (in case of acute intoxication)Saline Administrations: the goal of saline administration is to restore GFR, normalize urine output and enhance lithium clearance.Haemodialysis remains the mainstay treatment for lithium toxicity as lithium is readily dialyzed because of water solubility, low volume of distribution, and lack of protein binding.The Extracorporeal Treatments in Poisoning Workgroup (EXTRIP Workgroup) recommendations for dialysis (extracorporeal treatment) in lithium toxicity include:• Impaired kidney function and lithium levels > 4.0 mEq/L• Decreased consciousness, seizures, or life-threatening dysrhythmias, regardless of lithium levels• Levels are > 5.0 mEq/L, significant confusion is noted, or the expected time to reduce levels to < 1.0 mEq/L is more than 36 hoursAs post-dialysis rebound elevations in lithium levels have been documented, continuous veno-venous hemofiltration (CVVH) has been advocated.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 21
Correct
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The following are Gram positive rods:
Your Answer: Clostridia
Explanation:Examples of Gram positive bacilli:Bacillus genusClostridium genusCorynebacterium genusListeria genusPropionibacterium genusExamples of Gram negative bacilli:Bacteroides genusCitrobacter genusEnterobacter genusEscherichia genusPseudomonas genusProteus genusSalmonella genusSerratia genusShigella genusYersinia genus
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 22
Correct
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Which of the following has the shortest duration:
Your Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Correct
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Which of the following would provide relief from nausea and vomiting?
Your Answer: Cannabinoids
Explanation:Ondansetron, chlorpromazine and haloperidol are effective antiemetic agents. Corticosteroids, cannabinoids, and benzodiazepines, alone or in combination with 5-HT3 and D2 antagonists, are also useful in the treatment of vomiting produced by chemotherapy.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 24
Correct
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Which mechanism of action does Penicillin use?
Your Answer: Inhibit cell wall synthesis
Explanation:Bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide. β-Lactam antibiotics inhibit the formation of peptidoglycan cross-links in the bacterial cell wall; this is achieved through binding of the four-membered β-lactam ring of penicillin to the enzyme DD-transpeptidase. As a consequence, DD-transpeptidase cannot catalyse formation of these cross-links, and an imbalance between cell wall production and degradation develops, causing the cell to rapidly die.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 25
Correct
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Which of the following is not a cause of drug-induced hepatitis?
Your Answer: Ethambutol
Explanation:Although rare, ocular toxicity in the form of optic neuritis (most commonly retrobulbar neuritis) has been well documented as a side effect of ethambutol. It is renally excreted and not associated with hepatitis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 26
Correct
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Of the daily production of CSF, the vast majority is produced in the:
Your Answer: Choroid plexus
Explanation:About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 27
Correct
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Hydroxyl radicals are broken down by which of the following substance?
Your Answer: Antioxidants
Explanation:Unlike superoxide, which can be detoxified by superoxide dismutase, the hydroxyl radical cannot be eliminated by an enzymatic reaction but it is believed can be counteracted by antioxidants.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 28
Correct
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Anti-gastroesophageal reflux mechanisms include the following except:
Your Answer: Peristaltic movements of the oesophagus
Explanation:The lower oesophageal sphincter contracts preventing reflux of acid into the oesophagus. The sling muscles of the stomach, the crura of the diaphragm and the phreno-oesophageal ligament all play an important role in constricting the lower portion of the oesophagus and preventing reflux. Peristaltic movements do not stop the acid reflux.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Incorrect
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Renin is secreted by which of the following cells?
Your Answer: Principal cells
Correct Answer: Juxtaglomerular cells
Explanation:The juxtaglomerular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles, and some in the efferent arterioles, that deliver blood to the glomerulus.
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This question is part of the following fields:
- Medicine
- Renal
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Question 30
Correct
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Regarding glomus cells, which of the following is true?
Your Answer: Contain catecholamines
Explanation:The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide. Furthermore, it is also sensitive to changes in pH and temperature.The carotid body is made up of two types of cells, called glomus cells: Glomus type I/chief cells release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory centre.Glomus type II/sustentacular cells resemble glia, express the glial marker S100 and act as supporting cells.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 31
Incorrect
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Concerning surface anatomy, where is the mitral valve found?
Your Answer: Situated in the 4th intercostal space in the mid clavicular line
Correct Answer: Situated in the 4th intercostal space to the left of the sternum
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 32
Correct
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What is a characteristic findings on ECG in hyperkalaemia?
Your Answer: Tall, tented T waves
Explanation:Hyperkalaemia leads to:
– Prolonged PR interval
– Small P waves
– Tall, tented T waves
– Widened QRS complexes and eventually asystole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Correct
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Myocardial oxygen consumption is increased by:
Your Answer: An increase in after load
Explanation:Cardiac oxygen consumption is directly related to the amount of tension that develops in the ventricles. It is increased by an increased size of heart, increased afterload, increased contractility and increased heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 34
Correct
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Closure of the tricuspid valve is marked by which of the following features of the jugular venous waveform?
Your Answer: c wave
Explanation:The jugular venous pressure (JVP) classically has three upward deflections and two downward deflections. The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling. The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 35
Correct
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In Argyll Robertson pupils…
Your Answer: All of the options given
Explanation:Argyll Robertson pupils are bilaterally small pupils that accommodate or reduce in size near an object but do not react to light. They do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis but may be seen in diabetic neuropathy as well.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 36
Correct
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Which of the following is a granulocyte?
Your Answer: Eosinophil
Explanation:Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. There are three principal types of granulocytes, distinguished by their appearance under Wright’s stain:
- Basophil granulocytes
- Eosinophil granulocytes
- Neutrophil granulocytes
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This question is part of the following fields:
- Haematology
- Medicine
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Question 37
Correct
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Question 38
Correct
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When is the blood pressure at its lowest during pregnancy?
Your Answer: Second trimester
Explanation:It is lowest during the second trimester.
Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 39
Correct
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From which of the following can niacin be synthesized in humans
Your Answer: Tryptophan
Explanation:Niacin, is also known as vitamin B3. The liver can synthesize niacin from the essential amino acid tryptophan, requiring 60 mg of tryptophan to make one mg of niacin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 40
Correct
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A 25-year-old male presented to accident and emergency 4 days ago, following an intentional paracetamol overdose. He had taken 20x 500mg tablets, all at once. He denies any alcohol intake. Blood investigations 4 hours after ingestion showed:Paracetamol: 14 mg/lINR: 1Liver enzymes: No abnormality detectedBilirubin: Mild elevationHe was seen by the mental health team and discharged. The blood investigations were repeated:Bilirubin: Within normal limitsUrea: 21 mmol/lCreatinine: 300 µmol/lWhat is the likely cause of these results?
Your Answer: Delayed paracetamol nephrotoxicity
Explanation:The most likely cause for these results is delayed paracetamol nephrotoxicity.The blood investigations of this patient are highly suggestive of acute kidney injury. Paracetamol overdose is well known to cause hepatotoxicity, but not for its delayed nephrotoxicity, especially in significant overdose. Appropriate monitoring of a patient’s blood tests is important.Management:NAC (N-Acetyl cysteine) has a clear role in preventing acetaminophen-induced liver necrosis. Although NAC has not been proven to be harmful to the kidney, its role in patients without hepatoxicity and only isolated renal dysfunction is uncertain.Other options:-There are no features in the history that are suggestive of dehydration and pre-renal AKI presenting in this manner in a 25-year-old would be very unusual.- Minimal change nephropathy typically presents with a nephrotic picture of kidney injury.- Berger’s more commonly presents with isolated haematuria.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 41
Correct
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Which of the following cancers is responsible in producing osteoblastic bone metastases instead of osteolytic?
Your Answer: Prostate adenocarcinoma
Explanation:Osteoblastic (or sclerotic) bone metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 42
Correct
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Which of the following is the most common causative organism in infective endocarditis?
Your Answer: Streptococcus viridans
Explanation:Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 43
Correct
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The Plateau phase in myocyte action potentials does all of the following except:
Your Answer: It allows early reactivation of the myocytes
Explanation:The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 44
Correct
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Question 45
Correct
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Regarding CSF:
Your Answer: Disruption of arachnoid villi function results in a communicating hydrocephalus
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of the entire volume of cerebrospinal fluid is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has different electrolyte levels. Blockage of the foramina causes an obstructive or non-communicating hydrocephalus. Communicating hydrocephalus or non-obstructive hydrocephalus is caused by impaired CSF reabsorption in the absence of any CSF flow obstruction.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 46
Correct
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Choose the most correct answer, what reduces affinity for oxygen in haemoglobin?
Your Answer: All the options are true
Explanation:The strength with which oxygen binds to haemoglobin is affected by several factors. These factors shift or reshape the oxyhaemoglobin dissociation curve. A rightward shift indicates that the haemoglobin under study has a decreased affinity for oxygen. The causes of shift to right can be remembered using the mnemonic, CADET, face Right! for CO2 and CO, Acid (H+), 2,3-DPG, Exercise and Temperature.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 47
Correct
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Activation of baroreceptor reflex involves:
Your Answer: Short term regulation of systemic blood pressure
Explanation:Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 48
Incorrect
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What is the most abundant cell type in the central nervous system called?
Your Answer: Microglia
Correct Answer: Astrocyte
Explanation:Astrocytes are the supporting cells of the central nervous system. There are two types; the fibrous type is found in the white matter and the protoplasmic type in the grey matter. They are the most abundant cell type in the CNS.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 49
Correct
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Which enzyme is responsible for the removal of acetylcholine from the synapse?
Your Answer: Acetylcholinesterase
Explanation:Acetylcholinesterase is the enzyme that is responsible for breaking down acetylcholine into choline and acetate. Both of these molecules are transported back to the presynaptic neuron to be synthesized again. This enzyme is attached to the collagen fibers of the basement membrane in the synaptic cleft.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 50
Correct
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In liver failure there is likely to be?
Your Answer: Bleeding disorders
Explanation:Liver failure can lead to several significant changes in the body’s physiology, but let’s review each option in the context of liver failure:
- Raised blood urea: This is not typical of liver failure. In liver failure, blood urea nitrogen (BUN) levels are often low because the liver is not effectively converting ammonia to urea.
- Increase in the albumin/globulin ratio in the blood: This is incorrect. In liver failure, albumin production decreases, leading to a lower albumin/globulin ratio.
- Bleeding disorders: This is possible, but it often fluctuates. Liver failure can lead to both bleeding tendencies due to decreased production of clotting factors and a hypercoagulable state due to the reduced synthesis of anticoagulant proteins like Protein C and S.
- Stable blood glucose level: This is incorrect. Liver failure often causes hypoglycemia because the liver’s ability to produce glucose via gluconeogenesis and glycogenolysis is impaired.
- Increased absorption of fat: This is incorrect. Liver failure can lead to decreased bile production, which is necessary for fat emulsification and absorption, resulting in decreased fat absorption.
Given these points, the most likely option related to liver failure would actually be issues related to bleeding complications.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 51
Correct
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On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your Answer: Α2 receptor
Explanation:Adregenic receptors are A1, A2, B1, B2, B3. Out of these, the function of the A2 receptor is inhibition of transmitter release including nor adrenalin and acetylcholine of the autonomic nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 52
Correct
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Regarding the surface anatomy of the orifices of the heart, where is the aortic valve located?
Your Answer: Opposite the left 3rd intercostal space to the left of the sternum
Explanation:The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 53
Correct
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The heart rate can be accelerated by:
Your Answer: Exercise and thyroid hormones
Explanation:The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 54
Correct
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During which phase are the 2 chromatids pulled apart at the centromere?
Your Answer: Anaphase
Explanation:During the prometaphase the microtubule organizing centre completely develops. The spindle fibers attach to the chromosome and the centriole. It is in the Anaphase however that the spindle fibers contract pulling the sister chromatids apart. Later in the anaphase a cleave furrow beings to forms.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 55
Correct
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A 51-year-old real estate agent takes hydrocortisone 20mg in the mornings and 5mg at night for Addison’s disease. The endocrinology consultant would like her to take prednisolone instead. What dose of prednisolone should be started?
Your Answer: 7 mg
Explanation:1mg Prednisolone = 4mg hydrocortisone, so the actual equivalent daily dose is 7mg.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 56
Correct
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A 50-year-old male was brought to the ER after the accidental consumption of 300 ml of diethylene glycol. Blood investigations were suggestive of metabolic acidosis and renal failure. What is the appropriate management in this patient?
Your Answer: Haemodialysis and oral ethanol
Explanation:Among the given options the most appropriate management in this patient would be ethanol and haemodialysis.Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 57
Correct
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A 40-year-old man is admitted to the Emergency Department in a confused state. He tells you that he consumed two bottles of antifreeze. On examination, his pulse is 120 bpm and blood pressure is 140/90 mmHg. An arterial blood gas analysis shows uncompensated metabolic acidosis. He is transferred to the high dependency unit and ethanol is given via a nasogastric tube. How does ethanol help this patient?
Your Answer: Competes with ethylene glycol for alcohol dehydrogenase
Explanation:Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 58
Correct
-
After exercise, O2 debt repay may take up to:
Your Answer: 90 min
Explanation:Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 59
Correct
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What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?
Your Answer: Shifts the diastolic pressure curve upward and leftward
Explanation:Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 60
Correct
-
A 25-year-old student consumed a bottle of vodka at a party, the next day he finds that he feels excessively thirsty and is passing more urine than usual. Which of the following mechanisms best explains the polyuria due to excessive alcohol consumption?
Your Answer: Ethanol inhibits ADH secretion
Explanation:Ethanol reduces the calcium-dependent secretion of anti-diuretic hormone (ADH) by blocking channels in the neurohypophyseal nerve terminal.Thus, ethanol’s inhibitory effect helps to explain the increased diuresis experienced during intoxicated states as well as increased free water loss; without appropriate ADH secretion, more water is excreted by the kidneys.Nausea associated with hangovers is mainly due to vagal stimulation to the vomiting centre. Following a particularly severe episode of alcohol excess, people may experience tremors due to increased glutamate production by neurons to compensate for the previous inhibition by ethanol.Management of alcoholism:Nutritional support: – Alcoholic patients should receive oral thiamine if their ‘diet may be deficient’.Pharmacological management:- Benzodiazepines for acute withdrawal- Disulfiram promotes abstinence – alcohol intake causes a severe reaction due to inhibition of acetaldehyde dehydrogenase. Patients should be aware that even small amounts of alcohol (e.g. In perfumes, foods, mouthwashes) can produce severe symptoms. Contraindications include ischaemic heart disease and psychosis.- Acamprosate reduces craving, known to be a weak antagonist of NMDA receptors, improves abstinence in placebo-controlled trials.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 61
Correct
-
The central veins in the liver:
Your Answer: Coalesce to form the hepatic vein
Explanation:The central veins coalesce to form the hepatic vein which in turn drains into the inferior vena cava. The portal vein mainly carries blood from different parts of the GIT and is not drained to the inferior vena cava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 62
Correct
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A 35-year-old male was brought to you in a confused state. Although not your patient, you can make out that the man has a history of schizophrenia, and has recently had his medications altered. Clinically, you find evidence of a lower respiratory tract infection, and blood investigations indicate a neutropenic picture.What is the most likely drug causing the neutropenia?
Your Answer: Clozapine
Explanation:Clozapine can cause neutropenia or agranulocytosis.Clozapine is an atypical antipsychotic used in the treatment of schizophrenia, and in patients who are intolerant to, or unresponsive to other antipsychotics. It is a weak D2-receptor and D1-receptor blocking activity, with noradrenolytic, anticholinergic, and antihistaminic properties.Many antipsychotic drugs can occasionally cause bone marrow depression, but agranulocytosis is particularly associated with clozapine.Other side effects include:Hypotension, tachycardiaFever, sedation, seizures (with high doses)Appetite increaseConstipationHeartburnWeight gainExtrapyramidal symptomsAgranulocytosisNeuroleptic malignant syndrome
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 63
Correct
-
In the malaria life cycle , parasites which remain dormant in the liver are known as :
Your Answer: Hypnozoites
Explanation:The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 64
Correct
-
Which of the following statements correctly describes a function of the parasympathetic innervation of the GI tract.
Your Answer: Parasympathetic cholinergic activity increases the activity of intestinal smooth muscle
Explanation:The parasympathetic nerves stimulate peristalsis and relax the sphincters; they also stimulate secretion. Acetylcholine is the neurotransmitter of the parasympathetic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 65
Correct
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Regarding gustatory sensation:
Your Answer: The sensory taste buds on the anterior two-thirds of the tongue travel to the chorda tympani branch of the facial nerve
Explanation:There are three morphologically distinct types of taste buds including; circumvallate, fungiform and foliate. Circumvallate are rounded structures arranged in a v on the back of the tongue. The posterior third travels to glossopharyngeal nerve.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 66
Correct
-
The first enzyme carbohydrates encounter in the digestive tract is?
Your Answer: Amylase
Explanation:Carbohydrate digesting enzymes are known as amylase. Salivary amylase or ptyalin is the first enzyme to begin carbohydrate digestion in he oral cavity. Amylose is a component of carbohydrates and is not an enzyme. Isomaltase, maltase and sucrase are enzymes found in the small intestines that digest disaccharides like maltose and sucrose to monosaccharides.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 67
Correct
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Which of the following is a method for measurement of cardiac output?
Your Answer: Indicator dilution method
Explanation:There are two methods of calculating the cardiac output in humans other than doppler with echocardiography: The direct Fick’s method and the indicator dilution method. In the indicator dilution technique, a known amount of a substance such as a dye or, more commonly, a radioactive isotope is injected into an arm vein and the concentration of the indicator in serial samples of arterial blood is determined. The output of the heart is equal to the amount of indicator injected divided by its average concentration in arterial blood after a single circulation through the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 68
Incorrect
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A 67 year old man reports weight loss. Labs show a raised alkaline phosphatase at 290 U/L (normal range 35-120). Plain radiographs reveal sclerotic lesions of the bone. Which of the following is the most likely cause of these findings?
Your Answer: Osteomalacia
Correct Answer: Prostate cancer
Explanation:Osteoblastic (or sclerotic) bony metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma. The other cancers listed in the options are osteolytic.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 69
Correct
-
An example of cholinergic autonomic neurons are:
Your Answer: Sympathetic postganglionic neurons that innervate sweat glands.
Explanation:All preganglionic neurons in both the sympathetic and parasympathetic nervous system secrete acetylcholine. The postganglionic neurotransmitter of the parasympathetic nervous system in all neurons is acetylcholine. Postganglionic fibers of the sympathetic nervous system mainly secrete Noradrenalin and Adrenalin but at sweat glands and erector pili muscles the postganglionic neurotransmitter is acetylcholine.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 70
Correct
-
Mutation in RB can lead to the formation of which cancer?
Your Answer: Retinoblastoma
Explanation:Patients with a history of autosomal dominant familial retinoblastoma have at least one mutated copy of the RB gene. This predisposes the patient to develop retinoblastoma in one or both the eyes. Patients with a family history should be screened properly so that it can be detected and treated as early as possible.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 71
Correct
-
Which of the following stimulate the release of aldosterone from the adrenal cortex?
Your Answer: Angiotensin 2
Explanation:Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the renal tubules to increase the reabsorption of sodium and water into the blood, while at the same time causing the excretion of potassium (to maintain electrolyte balance).
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This question is part of the following fields:
- Medicine
- Renal
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Question 72
Incorrect
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Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?
Your Answer: Phase 4 : slow repolarization process
Correct Answer: Phase 1 : rapid repolarization
Explanation:Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 73
Correct
-
A 35-year-old female has been recently diagnosed with hypertension. She's sexually active and is not using any birth control other than barrier method. Which among the following antihypertensives is contraindicated in this patient?
Your Answer: Lisinopril
Explanation:Among the following hypertensives, lisinopril (an ACE inhibitor) is contraindicated in patients who are planning for pregnancy.Per the NICE guidelines, when treating the woman in question, she should be treated as if she were pregnant given the absence of effective contraception. ACE inhibitors such as lisinopril are known teratogens and most be avoided.Drugs contraindicated in pregnancy:AntibioticsTetracyclinesAminoglycosidesSulphonamides and trimethoprimQuinolonesOther drugs:ACE inhibitors, angiotensin II receptor antagonistsStatinsWarfarinSulfonylureasRetinoids (including topical)Cytotoxic agentsThe majority of antiepileptics including valproate, carbamazepine, and phenytoin are known to be potentially harmful.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 74
Correct
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Question 75
Correct
-
In the event of an overdose, haemodialysis is ineffective as a treatment modality for which of the following drugs?
Your Answer: Tricyclics
Explanation:Tricyclic compounds can’t be cleared by haemodialysis.Drugs that can be cleared with haemodialysis include: (BLAST)- Barbiturate- Lithium- Alcohol (inc methanol, ethylene glycol)- Salicylates- Theophyllines (charcoal hemoperfusion is preferable)Drugs which cannot be cleared with haemodialysis include:- Tricyclics- Benzodiazepines- Dextropropoxyphene (Co-proxamol)- Digoxin- Beta-blockers
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 76
Correct
-
The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer: Ia
Explanation:Muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is gamma motor neurone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 77
Correct
-
Tumour necrosis factor is a cytokine. What is its major function?
Your Answer: Promotion of inflammation
Explanation:Tumour necrosis factor (TNF) is a cytokine that has a wide variety of functions. It can cause cytolysis of certain tumour cell lines; it is involved in the induction of cachexia; it is a potent pyrogen, causing fever by direct action or by stimulation of interleukin-1 secretion; it can stimulate cell proliferation and induce cell differentiation under certain conditions.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 78
Correct
-
Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are true except:
Your Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In RFLP, polymorphism occurs in 98% of the non coding genome, resulting in no phenotypical change in the organism. A gene is not turned on by a mutation, rather the mutation at the restriction site will alter the DNA and the DNA will now form fragments of different lengths. PCR is a better technique than RFLP.
A knockout, as related to genomics, refers to the use of genetic engineering to inactivate or remove one or more specific genes from an organism. Scientists create knockout organisms to study the impact of removing a gene from an organism, which often allows them to then learn something about that gene’s function.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 79
Correct
-
What effect does osmotic diuresis have on net Na+ excretion?
Your Answer: Markedly increased Na+ excretion
Explanation:Osmotic diuresis is the increase of urination rate caused by the presence of certain substances in the small tubes of the kidneys. The excretion occurs when substances such as glucose enter the kidney tubules and cannot be reabsorbed (due to a pathological state or the normal nature of the substance). The substances cause an increase in the osmotic pressure within the tubule, causing retention of water within the lumen, and thus reduces the reabsorption of water, increasing urine output (i.e. diuresis). Sodium, chloride, potassium are markedly excreted in osmotic diuresis.
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This question is part of the following fields:
- Medicine
- Renal
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Question 80
Correct
-
Coronary flow is reduced during
Your Answer: Tachycardia
Explanation:Maximum amount of blood flow in the coronary arteries occur during diastole. When the heart rate increases which is also called tachycardia the duration of diastole decreases. Hence the amount of blood flow to the cardiac muscle also decreases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 81
Correct
-
The coronary arteries supply which part of the heart’s subendocardial region exclusively in diastole?
Your Answer: Left ventricle
Explanation:It is only during diastole that the blood flows to the subendocardial portion of the left ventricle, as the heart muscle relaxes and the coronary arteries regain their patency.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 82
Correct
-
Which is the primary lymphoid organ?
Your Answer: Thymus
Explanation:Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 83
Correct
-
The pyloric sphincter is largely made up of thickening of
Your Answer: The circular muscle layer
Explanation:The pyloric sphincter, or valve, is a strong ring of smooth muscle (circular muscle layer) at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum. It receives sympathetic innervation from the celiac ganglion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 84
Correct
-
Myelin sheath in the CNS is produced by?
Your Answer: Oligodendrocytes
Explanation:CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function — to promote efficient transmission of a nerve impulse along the axon.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 85
Correct
-
A 78-year-old male with long-standing Alzheimer's disease is being reviewed in your clinic. Which among the following is true regarding memantine, a drug which has been approved for the management of dementia?
Your Answer: It is an NMDA-receptor antagonist
Explanation:Memantine is an antagonist of the NMDA (N-Methyl-D-Aspartate)-receptor subtype of glutamate receptor. It is used to slow the neurotoxicity thought to be involved in Alzheimer’s disease and other neurodegenerative diseases.
Drug interactions:
- When given concomitantly with other NMDA-receptor antagonists (e.g., ketamine, amantadine) there is increased risk of psychosis.
- Dopamine agonists, L-dopa, and anticholinergics enhance effects of memantine.
- Antispasmodics (e.g., baclofen) enhance effects, as memantine has some antispasmodic effects.
- Drugs excreted by cationic transporters in the kidney (e.g. quinine, cimetidine, ranitidine) reduce excretion.
- Common adverse effects include dizziness, headache, confusion, diarrhoea, and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 86
Correct
-
Microtubule disassembly:
Your Answer: Occurs at the positive and negative end
Explanation:Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region. Although both assembly and disassembly occur at both ends they occur preferentially at the (+) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 87
Correct
-
Cold receptors are likely to be active at the following temperatures except?
Your Answer: 39 °C
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is primarily responsible for the detection of temperatures ranging from 8-28 C. It is an ion channel which upon activation causes the influx of Na+ and Ca+ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 88
Incorrect
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Question 89
Correct
-
The following play a role in regulation of intestinal iron absorption except:
Your Answer: Urinary iron excretion rate
Explanation:The human body’s rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, dietary intake, the extent to which the bone marrow is producing new red blood cells, the concentration of haemoglobin in the blood, and the oxygen content of the blood. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 90
Correct
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Question 91
Incorrect
-
The position of the kidneys besides the vertebral column retroperitoneally spans levels:
Your Answer: T11 – L2
Correct Answer: T12 – L3
Explanation:The asymmetry within the abdominal cavity, caused by the position of the liver, typically results in the right kidney being slightly lower and smaller than the left, and being placed slightly more to the middle than the left kidney. The left kidney is approximately at the vertebral level T12 to L3, and the right is slightly lower.
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This question is part of the following fields:
- Medicine
- Renal
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Question 92
Correct
-
The chemosensitive area in the medulla responds to:
Your Answer: High hydrogen and high carbon dioxide
Explanation:The chemosensitive area in the medulla responds mainly to high pH levels and carbon dioxide levels. Baroreceptors in the carotid and aortic body respond mainly to oxygen and carbon dioxide partial pressure in blood.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 93
Correct
-
A 72 year old retired fisherman presents with weakness of shoulders and hips over the last four months. Finger flexion is also weak but the extension is normal. There has been some difficulty swallowing liquids. Past medical history is not significant except for sexually transmitted disease that he caught some 40 years ago in South Pacific and got treated with antibiotics. He smokes and drinks one or two tots of rum at the weekend. Creatine kinase level is 125. Which of the following investigations is most significant in establishing a diagnosis?
Your Answer: Muscle biopsy with electron microscopy
Explanation:Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and wrists. Some people also have weakness of the facial muscles (especially muscles controlling eye closure), or difficulty swallowing (dysphagia). Muscle cramping and pain are uncommon, but have been reported in some people. The underlying cause of IBM is poorly understood and likely involves the interaction of genetic, immune-related, and environmental factors. Some people may have a genetic predisposition to developing IBM, but the condition itself typically is not inherited. Elevated creatine kinase (CK) levels in the blood (at most ,10 times normal) are typical in IBM. Muscle biopsy may display several common findings including; inflammatory cells invading muscle cells, vacuolar degeneration, inclusions or plaques of abnormal proteins.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 94
Correct
-
Which of the following does not contribute to increased stroke volume during exercise?
Your Answer: Increased length of filling time during diastole
Explanation:Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 95
Correct
-
What is the most appropriate management of a DVT during pregnancy?
Your Answer: Heparin
Explanation:Low molecular weight heparin (LMWH) is safe in pregnancy and is therefore the first line management. Warfarin is teratogenic and must be avoided whilst the other options have no role to play.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 96
Correct
-
Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms
Your Answer: Increased phosphorylation of phosholamban
Explanation:Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 97
Correct
-
Which of the following forms the language areas of the cerebral cortex?
Your Answer: All of the above
Explanation:Broca’s area, Wernicke’s area, the submarginal sulcus and the angular gyrus all form the language areas of the cerebral cortex.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 98
Correct
-
Pacemaker cells in the SA node and the AV node are connected by?
Your Answer: Gap junctions
Explanation:Gap junctions allows for rapid propagation of the action potential from one cell to the other. The cells of the heart are connected by gap junctions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 99
Correct
-
Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 100
Incorrect
-
Vitamin B12 is transported from the enterocytes to the bone marrow by which factor?
Your Answer: Transcobalamin I (TC 1)
Correct Answer: Transcobalamin II (TC IIi)
Explanation:B12 must be attached to IF for it to be efficiently absorbed, as receptors on the enterocytes in the terminal ileum of the small bowel only recognize the B12-IF complex. Once the IF/B12 complex is recognized by specialized ileal receptors, it is transported into the portal circulation. The vitamin is then transferred to transcobalamin II (TC-II/B12), which serves as the plasma transporter.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 101
Correct
-
Which of the following is NOT a component of bile?
Your Answer: Unconjugated bilirubin
Explanation:The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts (electrolytes).
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 102
Correct
-
A 60-year-old male is under treatment with azathioprine after a renal transplant. During his review, he complains of pain and swelling over his left great toe. Investigations reveal hyperuricemia. Suspecting gout, he was started on allopurinol. Subsequently, he develops aplastic anaemia. Which of the following is the most appropriate reason for his bone marrow failure?
Your Answer: Mercaptopurine toxicity
Explanation:The cause for bone marrow suppression in this patient is most probably mercaptopurine toxicity.Azathioprine is metabolized to 6-mercaptopurine (6-MP), which itself is metabolized by xanthine oxidase. Xanthine oxidase inhibition by allopurinol leads to the accumulation of 6-MP which then precipitates bone marrow failure. This may be potentially fatal if unrecognized.Clinical presentation:Toxicity symptoms include gastrointestinal symptoms, bradycardia, hepatotoxicity, myelosuppression.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 103
Correct
-
The percentage of blood supplied to the liver by the hepatic artery is?
Your Answer: 25%
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow. Oxygen is provided from both sources; approximately half of the liver’s oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 104
Correct
-
The majority striatal neurons, called medium spiny neurons, utilizes which neurotransmitter?
Your Answer: GABA
Explanation:Medium spiny neurons are inhibitory neurons which use GABA (gamma-aminobutyric acid) which exerts inhibitory actions. These cells represent 95% of neurones within the human striatum found in basal ganglia.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 105
Correct
-
A 55-year-old male presents with complaints suggestive of erectile dysfunction. He also provides a history of ischaemic heart disease for which he is under treatment. The GP decides to start him on sildenafil citrate. Which of the following medications may contraindicate the use of sildenafil in this patient?
Your Answer: Nicorandil
Explanation:The use of nitrates and nicorandil concomitantly with sildenafil citrate is contraindicated.Sildenafil (Viagra) is a phosphodiesterase type V inhibitor used in the treatment of impotence.Contraindications- Patients taking nitrates and related drugs such as nicorandil- Hypotension- Recent stroke or myocardial infarction (NICE recommend waiting 6 months)Side-effects:Visual disturbances e.g. cyanopsia, non-arthritic anterior ischaemic NeuropathyNasal congestionFlushingGastrointestinal side-effectsHeadache
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 106
Incorrect
-
Regarding Southern Blotting and DNA probes, which answer is FALSE
Your Answer: DNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in southern blotting
Correct Answer: RNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in southern blotting
Explanation:Restriction enzymes always cut at different positions. There are different restriction endonucleases for different nucleotide sequences.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 107
Correct
-
What is the name of the area that indicates the site of active B lymphocyte proliferation?
Your Answer: Germinal centre
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 108
Correct
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Question 109
Correct
-
Normally the portal venous pressure is about:
Your Answer: 5mmhg
Explanation:Under normal physiological conditions, the pressure in the portal vein, which carries blood from the gastrointestinal tract and spleen to the liver, typically ranges around 5-10 mmHg. Pressures significantly higher than this range can indicate portal hypertension, which can be associated with liver diseases such as cirrhosis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 110
Correct
-
Which of the following statements is not true about mitochondrial chromosomes?
Your Answer: Mitochondrial chromosomes play no role in the transmission of disease from generation to generation.
Explanation:All the above mentioned statements are true except that mitochondrial DNA is passed from the mother to the child. If the child inherits the defective mitochondrial gene it will manifest some form of the disease. Commonly inherited diseases related to mitochondrial abnormality are Leber hereditary optic neuropathy and myoclonic epilepsy with ragged red fibers (MERRF).
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This question is part of the following fields:
- Genetics
- Medicine
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Question 111
Incorrect
-
Which of the following are true when it comes to tumour suppressor genes:
Your Answer: Viruses can inactivate tumour suppressor genes
Correct Answer: All of the options are true
Explanation:All of the above mentioned statements are true regarding tumour suppressor genes. Tumour suppressor genes generally follow the two-hit hypothesis, which implies that both alleles that code for a particular protein must be affected before an effect is manifested.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 112
Correct
-
During quiet breathing the diaphragm’s role accounts for what percent of respiration?
Your Answer: 75%
Explanation:The contraction of the diaphragm accounts for approximately 75% of the air movement during normal breathing.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 113
Correct
-
Number of cases that are infected at a specific point in time
Your Answer: Prevalence
Explanation:Prevalence in epidemiology is the proportion of a population found to have a condition (typically a disease or a risk factor such as smoking or seat-belt use). It is arrived at by comparing the number of people found to have the condition with the total number of people studied, and is usually expressed as a fraction, as a percentage or as the number of cases per 10,000 or 100,000 people. Point prevalence is the proportion of a population that has the condition at a specific point in time. Period prevalence is the proportion of a population that has the condition at some time during a given period (e.g., 12 month prevalence), and includes people who already have the condition at the start of the study period as well as those who acquire it during that period. Lifetime prevalence (LTP) is the proportion of a population that at some point in their life (up to the time of assessment) have experienced the condition
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 114
Correct
-
A 74 year old man presents with 12 kg weight loss and persistent back pain that is unrelated to activity for the past several months. Laboratory findings show :WCC: 6.7 x 109/l (5.4 neutrophils, 1.2 lymphocytes and 0.2 monocytes)Haemoglobin: 11.2 g/dlhaematocrit: 33.3%MCV: 88 flPlatelet count: 89 x 109/l.The biochemistry shows:sodium 144 mmol/lpotassium 4.5 mmol/lchloride 100 mmol/lbicarbonate 26 mmol/lurea 14 mmol/lcreatinine 90 μmol/la glucose of 5.4 mmol/l.A CT scan of the spine reveals scattered 0.4 to 1.2 cm bright lesions in the vertebral bodies.Which of the following additional laboratory test findings is he most likely to have?
Your Answer: Serum prostate specific antigen of 35 microgram/l
Explanation:Old age, persistent backache, weight loss, and osteosclerotic lesions make prostatic adenocarcinoma the most likely diagnosis. The sequelae include severe pain, pathological fractures, hypercalcemia and cord compression. Prostatic adenocarcinoma is detected by elevated levels of prostate specific antigen. Positive serology for borrelia burgdorferi would hint at Lyme disease which does not cause osteosclerotic bone lesions, neither would Neisseria gonorrhoeae have such a presentation.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 115
Correct
-
Within the hypothalamus, the dopamine-secreting neurones of the intrahypothalamic system have their cell bodies in which nuclei?
Your Answer: Arcuate
Explanation:Arcuate nucleus dopaminergic neurons consist of a single group of neurons that project to the median eminence where they release dopamine into the hypophyseal portal circulation to inhibit pituitary prolactin secretion.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 116
Correct
-
With regards to the function of the p53 protein produced by the p53 gene, which of the following statements is incorrect?
Your Answer: It permits repair of mutations and other defects in RNA
Explanation:The p53 protein is a crucial tumor suppressor and plays several key roles in maintaining cellular integrity:
- Nuclear transcription factor: p53 is a nuclear transcription factor that regulates the expression of various genes involved in cell cycle control, DNA repair, apoptosis, and senescence.
- DNA repair: p53 permits repair of mutations and other defects in DNA (not RNA). It activates the transcription of genes involved in DNA repair mechanisms, allowing the cell to correct errors before proceeding with the cell cycle.
- Cell cycle regulation: p53 can induce the expression of p21, a protein that inhibits cyclin-dependent kinases, thereby halting the cell cycle at the G1/S checkpoint to allow time for DNA repair or to trigger apoptosis if the damage is irreparable. Mutations in p53 may fail to halt the cell cycle, allowing mutations to persist and potentially leading to cancer.
- Apoptosis: If DNA damage is extensive and cannot be repaired, p53 triggers apoptosis to prevent the propagation of damaged cells.
- Suppression of proto-oncogenes: p53 indirectly contributes to the suppression of proto-oncogenes by preventing the proliferation of cells with damaged DNA, thereby reducing the risk of oncogenic transformation.
Given these functions, the statement that p53 “permits repair of mutations and other defects in RNA” is incorrect, as p53 is primarily involved in the repair of DNA, not RNA.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 117
Incorrect
-
What is the role of cyclin and cyklin-dependent kinases in mitosis:
Your Answer: Causes splitting of the centromere
Correct Answer: Phosphorylation of proteins that make up pre-replication complexes
Explanation:There are certain regulators of the cell cycles that mediate progression through the cell cycle. These are cyclins and cyklin-dependent kinases (CDKs). They form a complex that phosphorylates protein involved in the cell cycle.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 118
Correct
-
Chief cells secrete:
Your Answer: Pepsinogen and gastric lipase
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 119
Correct
-
A 53-year-old female teacher asks about hormone replacement therapy (HRT). What is the most compelling indication for starting HRT?
Your Answer: Control of vasomotor symptoms such as flushing
Explanation:Hormone replacement therapy (HRT) involves the use of a small dose of oestrogen, combined with a progestogen (in women with a uterus), to help alleviate menopausal symptoms. The main indication is the control of vasomotor symptoms. The other indications, such as reversal of vaginal atrophy and prevention of osteoporosis, should be treated with other agents as first-line therapies.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 120
Incorrect
-
Afferent A δ fibers from nociceptors terminate primarily on neurons in which lamina:
Your Answer: III, IV, V, VI
Correct Answer: I and V
Explanation:Nociceptors are receptors of pain sensation. There are 2 primary afferent/sensory pain fibers which transmit impulses from the receptor to the CNS, specifically to the dorsal horn of the spinal cord. The two fibers are A δ and C fibers. The dorsal horn of the spinal cord is the relay centre for sensory information converging from the periphery. Grey matter of the dorsal horn is subdivided in to laminae based on cytoarchitecture. C fibers terminate in lamina II the substantia gelatinosa. A δ fibers terminate primarily in lamina I but some project more deeply to terminate in lamina V.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 121
Incorrect
-
Which of the following conditions is least likely to exhibit the Koebner phenomenon?
Your Answer: Vitiligo
Correct Answer: Lupus vulgaris
Explanation:The Koebner phenomenon refers to skin lesions appearing on lines of trauma, exposure to a causative agents including: molluscum contagiosum, warts and toxicodendron dermatitis or secondary to scratching rather than an infective or chemical cause include vitiligo, psoriasis, lichen planus, lichen nitidus, pityriasis rubra pilaris, and keratosis follicularis (Darier disease).
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 122
Correct
-
Which statement regarding fever is correct:
Your Answer: Body temperature is regulated is by a centre in the floor of the third ventricle
Explanation:The hypothalamus is located on the floor of the third ventricle and is the centre of regulation of body temperature. It uses a set point to regulate other body systems as well. Diurnal variation of temperature is not seen in humans. the principal mediator of fever is interleukin I, although interferon alfa also plays a role. Fever can cause rhabdomyolysis or muscle breakdown
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 123
Correct
-
Absolute refractory period in a cardiac action potential graph occurs during.
Your Answer: All of the above
Explanation:Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 124
Correct
-
A 42 year old male arrives at the clinic due to cough and haemoptysis. Examination shows nasal mucosal ulceration. The doctor suspects Wegener's granulomatosis. Which anatomical area would be most commonly involved in this condition?
Your Answer: Lungs
Explanation:Granulomatosis with polyangiitis (GPA, previously known as Wegener’s granulomatosis) is a systemic vasculitis that affects both small and medium-sized vessels. Patients typically initially suffer from a limited form that may consist of constitutional symptoms and localized manifestations such as chronic sinusitis, rhinitis, otitis media, ocular conditions. In later stages, more serious manifestations may arise, including pulmonary complications and glomerulonephritis, although the skin, eyes, and heart may also be involved but these lesions are less common. Diagnosis is based on laboratory testing (positive for PR3-ANCA/c-ANCA), imaging, and biopsy of affected organs, which demonstrate necrotizing granulomatous inflammation. GPA is treated with immunosuppressive drugs, typically consisting of glucocorticoids combined with methotrexate, cyclophosphamide, or rituximab. Relapses are common and the following systems are affected: Lower respiratory tract (95% of cases), renal involvement (80% of cases), skin lesions (45% of cases), ocular involvement (45% of cases) and cardiac involvement (33% of cases).
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 125
Correct
-
A 32 year old woman presents with a painful elbow which she has been feeling for the past two weeks. Which of the following will be consistent with a diagnosis of tennis elbow?
Your Answer: Pain on wrist extension against resistance
Explanation:Lateral epicondylitis (tennis elbow) is an overuse injury of the hand and finger extensor tendons that originate in the lateral humeral epicondyle that occurs following repeated or excessive pronation/supination and extension of the wrist (e.g., in racquet sports). Clinical features include pain and tenderness over the lateral epicondyle and along extensor muscles and thickening of the tendons. The examiner holds the patient’s hand with the thumb placed over the lateral epicondyle – The patient makes a fist, supinates the forearm, deviates radially, and extends the fist against the examiner’s resistance which will result in pain over the lateral epicondyle. Conservative treatment includes rest, physiotherapy and orthotic braces. If this fails corticosteroids and lidocaine injections are employed. Surgery is indicated in patients with persistent symptoms despite 6 months of conservative treatment. Excision of abnormal tendon tissue; longitudinal incisions (tenotomies) in scarred and fibrotic areas to promote healing.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 126
Incorrect
-
The enzyme responsible for telomeres maintaining their length after cell division is called:
Your Answer: Telomere transcriptase
Correct Answer: Telomerase
Explanation:Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 127
Correct
-
In the gastric mucosa, which of the following cells is known to secrete gastric lipase?
Your Answer: Chief cell
Explanation:Chief cells produce pepsinogen and gastric lipase. Parietal cells produce stomach acid and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 128
Correct
-
The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 129
Correct
-
With regards to the deiodinases, where would you find D1?
Your Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 130
Correct
-
To which of the following plasma proteins is T4 most bound in plasma?
Your Answer: Thyroxine-binding globulin
Explanation:Thyroxine-binding globulin, also known as TBG, is one of the three transport proteins responsible for carrying T4 and T3 through the circulatory system. It carries most of the T4 present in plasma, which it binds to strongly, shielding the hydrophobic hormones from the aqueous surroundings.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 131
Correct
-
β-blockers are used in the treatment of angina because they have which one of the following properties?
Your Answer: Decrease the heart rate and myocardial contractility
Explanation:The cardiovascular effects of β-adrenoceptor block result from reduction of the sympathetic drive which includes reduced heart rate (automaticity) and reduced myocardial contractility (rate of rise of pressure in the ventricle). This will lead to reduced cardiac output and an overall fall in oxygen consumption.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 132
Correct
-
A 18-year-old female is brought to the emergency department by her boyfriend. He is concerned that she may have taken an overdose of her mom's morphine sulphate pills after being depressed about her mother, who is dying of carcinoma of the breast.Which of the following may point towards his suspicion?
Your Answer: Sweating
Explanation:Excessive sweating points towards a morphine overdose.Morphine is considered the classic opioid analgesic with which other painkillers are compared. Like other medications in this class, morphine has an affinity for delta, kappa, and mu-opioid receptors.Most commonly used in pain management, morphine provides major relief to patients afflicted with pain.Among the more common adverse effects of morphine use is constipation. Other side effects include nausea, vomiting, drowsiness, and confusion. Psychological and physical dependence may occur.Other side effects include bronchospasm, angioedema, urinary retention, ureteric or biliary spasm, dry mouth, sweating, rash, facial flushing, vertigo, tachycardia, bradycardia, palpitations, orthostatic hypotension, hypothermia, restlessness, mood change, hallucinations, seizures (adults and children) and miosis, headache and allergic reactions (including anaphylaxis) and decreased libido or potency.Raised intracranial pressure occurs in some patients. Muscle rigidity may occur with high doses. Elevated liver enzymes may occur due to biliary sphincter constriction. Large doses can lead to respiratory depression, circulatory failure, and coma.Treatment of opioid overdose:Initial treatment of overdose begins with supportive care.Naloxone is a pure competitive antagonist of opiate receptors and has no agonistic activity. The drug is relatively safe and can be administered intravenous, intramuscular, subcutaneous or via the endotracheal tube.Alternatively, nalmefene and naltrexone maybe considered.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 133
Correct
-
Regarding the formation of CSF, which of the following is true?
Your Answer: Its composition resembles that of brain ECF
Explanation:In normal adults CSF volume is around 125ml to 150ml. Turnover of entire volume of cerebrospinal fluid a day is about 3 to 4 times a day. Composition of CSF is similar to that of plasma except that CSF is nearly protein-free compared with plasma and has a different electrolyte level. About 80% of CSF is produced by the choroid plexus. It is also produced by a single layer of column shaped ependymal cells. The composition and rate of CSF generation depends on several factors and is influenced by hormones and the content and pressure of blood and CSF.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 134
Correct
-
Intrinsic Factor is released by,
Your Answer: Parietal cell
Explanation:Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 135
Correct
-
With regards to splenic micro-architecture which is not contained within the red pulp
Your Answer: Malpighian corpuscles
Explanation:Red pulp is responsible for mechanical filtration of red blood cells and is composed of sinusoids, which are filled with blood, splenic cords of reticular fibers and a marginal zone bordering on white pulp. White pulp provides an active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of: lymphoid follicles, rich in B-lymphocytes and periarteriolar lymphoid sheaths (PALS), rich in T-lymphocytes.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 136
Correct
-
A cohort study is being designed to look at the relationship between smoking and prostate cancer. What is the usual outcome measure in a cohort study?
Your Answer: Relative risk
Explanation:A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing a cross-section at intervals through time. The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Relative risk is used in the statistical analysis of the data of experimental, cohort and cross-sectional studies, to estimate the strength of the association between treatments or risk factors, and outcomes.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 137
Correct
-
Interruption of the entero-hepatic circulation causes:
Your Answer: The amount of fat in the stool to be increased
Explanation:Enterohepatic circulation refers to the circulation of biliary acids, bilirubin, drugs, or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver. One of the causes of the interruption of enterohepatic circulation is the resection of the ileum where fat is mainly absorbed. Fat malabsorption results in increased fat in stools. Pale stools and dark urine is caused by obstruction of the biliary ductal system especially the common bile duct where urobilin and stercobilin are formed.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 138
Incorrect
-
Where are the cell bodies of preganglionic neurons located?
Your Answer: Spinothalamic tract
Correct Answer: Lateral column
Explanation:The cell bodies of the preganglionic neurons are located in the lateral grey column of the spinal cord and in the motor nuclei of the 3rd, 7th, 9th and 10th cranial nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 139
Correct
-
A patient has been diagnosed with multi-drug resistant tuberculosis and is currently bring treated with rifampicin, isoniazid, and pyrazinamide. He is commenced on streptomycin.Which among the following is the most likely neurological side-effect of streptomycin?
Your Answer: Vestibular damage
Explanation:Vestibular damage is a neurological side effect of streptomycin.Streptomycin is an aminoglycoside bactericidal antibiotic. It is used in the treatment of tularaemia and resistant mycobacterial infections.The most common neurological side-effect is vestibular damage leading to vertigo and vomiting. Cochlear damage is less frequent and results in deafness. Other side-effects include rashes, angioneurotic oedema, and nephrotoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 140
Incorrect
-
Regarding cardiac contractility, catecholamines exert their inotropic effect via:
Your Answer: Β2-adrenergic receptors and gs
Correct Answer: Β1-adrenergic receptors and gs
Explanation:Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 141
Incorrect
-
A 28 year old female with a history of psoriatic arthritis would most likely have which of the following hand conditions?
Your Answer: Arthritis mutilans
Correct Answer: Nail dystrophy
Explanation:Nail dystrophy (pitting of nails, onycholysis, subungual hyperkeratosis), dactylitis, sausage shaped fingers are most commonly seen with psoriatic arthropathy. There is asymmetric joint involvement most commonly distal interphalangeal joints. Uveitis and sacroiliitis may also occur. Arthritis mutilans may occur but is very rare. Cutaneous lesions may or may not develop. When they do, its usually much after the symptoms of arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 142
Incorrect
-
Which one of the following conditions is least likely to be associated with pyoderma gangrenosum?
Your Answer: Rheumatoid arthritis
Correct Answer: Syphilis
Explanation:The following are conditions commonly associated with pyoderma gangrenosum:
Inflammatory bowel disease:
- Ulcerative colitis
- Crohn’s disease
Arthritides:
- Rheumatoid arthritis
- Seronegative arthritis
Haematological disease:
- Myelocytic leukaemia
- Hairy cell leukaemia
- Myelofibrosis
- Myeloid metaplasia
- Monoclonal gammopathy
Autoinflammatory disease:
- Pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome (PAPA syndrome)
- Granulomatosis with polyangiitis
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 143
Correct
-
Which of the following structures of the cardiac conduction system is located in the right posterior portion of the interatrial septum?
Your Answer: AV node
Explanation:AV node is located at the right posterior portion of the interatrial septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 144
Incorrect
-
Which of the following associations is false?
Your Answer: Maxillary nerve – foramen rotundum
Correct Answer: Mandibular nerve – foramen lacerum
Explanation:– The olfactory nerves pass through the cribriform plate- The maxillary division of the trigeminal nerve passes through the foramen rotundum- The facial nerve passes through the stylomastoid foramen- The mandibular division of the trigeminal nerve pass through the foramen ovale- The glossopharyngeal nerve passes through the jugular foramen.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 145
Incorrect
-
Which inhibitor of gastric enzyme secretion is released by the presence of fat in the jejunum?
Your Answer: Guanylin
Correct Answer: Peptide yy
Explanation:Peptide yy is secreted from the jejunum due to the presence of fat. It inhibits gastric acid secretion and motility.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 146
Correct
-
Question 147
Correct
-
Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 148
Correct
-
Into how many functional units can the cerebellum be divided?
Your Answer: 3
Explanation:The functional division of the cerebellum are the: Vestibulocerebellum (floculonodular lobe), Spinocerebellum (vermis and associated areas in the midline) and cerebrocerebellum (lateral hemispheres).
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This question is part of the following fields:
- Medicine
- Neurology
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Question 149
Correct
-
Vasodilatation of coronary arteries is caused by:
Your Answer: Hypoxia
Explanation:The heart is highly metabolically active and boasts the highest oxygen consumption by mass of any organ. This demand for oxygen is met by the coronary circulation, which is responsible for delivering blood to the myocardium and represents approximately 5% of cardiac output. Vasodilation may be due to the local effect of hypoxia on coronary vessels, or local metabolic vasodilation, or the activation of β-adrenoceptors or some combination of these mechanisms.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 150
Correct
-
Myocyte action potentials – Choose the false statement:
Your Answer: Repolarisation is due to net k+ influx
Explanation:Final repolarization (phase 3) to the resting membrane potential (phase 4) is due to closure of the Ca2+ channels and a slow, delayed increase of K+ efflux through various types of K+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
