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Question 1
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Which of the following acts to inhibit antidiuretic hormone (ADH) release from the posterior pituitary:
Your Answer: Atrial natriuretic peptide
Explanation:ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP).
ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 2
Correct
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C5 - C9 deficiency increases susceptibility to infection with which of the following:
Your Answer: Neisseria spp.
Explanation:If the complement sequence is completed, an active phospholipase (the membrane attack complex, MAC) is produced, which punches holes in the cell membrane and causes cell lysis. Because the MAC appears to be the sole means to destroy the Neisseria family of bacteria, C5 – C9 deficiency increases susceptibility to Neisseria infections.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 3
Correct
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Which of the following best describes the mechanism of action of aspirin:
Your Answer: Cyclo-oxygenase (COX) inhibitor
Explanation:Aspirin is a non-steroidal anti-inflammatory drug (NSAID). Aspirin irreversibly inhibits cyclooxygenase (COX) enzymes and the resulting inhibition of prostaglandin synthesis results in analgesic, antipyretic and to a lesser extent anti-inflammatory actions.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 4
Correct
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The myocardium is responsible for creating the force with which the atrial and ventricular muscles contract. It is made up of myocytes, which are heart muscle cells.
Which of the following statements about cardiac muscle anatomy is correct?Your Answer: Cardiac myocytes have intercalated discs
Explanation:Typically, granuloma has Langerhan’s cells (large multinucleated cells ) surrounded by epithelioid cell aggregates, T lymphocytes and fibroblasts.
Antigen presenting monocytic cells found in the skin are known as Langerhan’s cells.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 5
Correct
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Question 6
Correct
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A 59-year-old man presents with a goitre, increased sweating, weight loss, and palpitations. A diagnosis of hyperthyroidism is suspected.
What is the most appropriate first-line investigation?
Your Answer: TSH level
Explanation:A thyroid function test is used in the diagnosis of hyperthyroidism.
Serum TSH should be the first-line investigation for patients with suspected hyperthyroidism as it has the highest sensitivity and specificity for hyperthyroidism.A normal TSH level almost always excludes the diagnosis, though there are rare exceptions to this.
Antithyroglobulin antibodies are commonly present in Graves’ disease, but the test has a sensitivity of 98% and specificity of 99, and is not widely available.
Radioactive iodine uptake scan using iodine-123 – shows low uptake in thyroiditis but high in Graves’ disease and toxic multinodular goitre. It is however, not first-line investigation in this case
Thyroid ultrasound scan – is a cost-effective and safe alternative to the radioactive iodine uptake scan.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 7
Correct
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You examine a 79-year-old woman who has had hypertension and atrial fibrillation in the past. Her most recent blood tests show that she has severe renal impairment.
Which medication adjustments should you make in this patient's case?Your Answer: Reduce dose of digoxin
Explanation:Digoxin is excreted through the kidneys, and impaired renal function can lead to elevated digoxin levels and toxicity.
The patient’s digoxin dose should be reduced in this case, and their digoxin level and electrolytes should be closely monitored. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 8
Correct
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Question 9
Correct
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Which of the following is a contraindication for aspirin?
Your Answer: Children under 16 years
Explanation:Aspirin contraindications include: hypersensitivity to NSAIDs; asthma, rhinitis, and nasal polyps; and usage in children or teens.
There is little evidence of allergic cross-reactivity for salicylates. However, due to similarities in chemical structure and/or pharmacologic activities, the possibility of cross-sensitivity cannot be completely ruled out. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 10
Correct
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A 23-year-old man is discovered to have an infection from Helicobacter pylori.
Which of the following types of cancer is mostly associated with Helicobacter pylori infection?Your Answer: Gastric cancer
Explanation:H. pylori is recognized as a major cause of type B gastritis, a chronic condition formerly associated primarily with stress and chemical irritants. In addition, the strong association between long-term H. pylori infection and gastric cancer has raised more questions regarding the clinical significance of this organism. There is speculation that long-term H. pylori infection resulting in chronic gastritis is an important risk factor for gastric carcinoma resulting in H. pylori being classified as a carcinogen.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 11
Correct
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A 24-year-old man goes to the emergency department with a fever, headache, and swollen parotid glands that are excruciating. You have a suspicion that it is mumps. Which of the following nerves is causing the discomfort the patient is experiencing:
Your Answer: Auriculotemporal nerve
Explanation:The auriculotemporal nerve is irritated by mumps, which results in significant discomfort due to inflammation and swelling of the parotid gland, as well as the stretching of its capsule. Compression caused by swallowing or chewing exacerbates pain.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 12
Correct
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You see a patient in the Emergency Department with features consistent with a diagnosis of type I diabetes mellitus.
Which of these is MOST suggestive of type I diabetes mellitus?
Your Answer: History of recent weight loss
Explanation:A history of recent weight loss is very suggestive of an absolute deficiency of insulin seen in type I diabetes mellitus.
An age of onset of less than 20 years makes a diagnosis of type I diabetes mellitus more likely. However, an increasing number of obese children and young people are being diagnosed with type II diabetes.
Microalbuminuria, peripheral neuropathy, and retinopathy all occur in both type I and type II diabetes mellitus. They are not more suggestive of type I DM.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 13
Correct
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Which of the following cervical nerves is likely to be affected if your patient is complaining of elbow extension weakness and loss of sensation in her middle finger? She also has pain and tenderness in her cervical region, which is caused by a herniated disc, all after a whiplash-type injury in a car accident.
Your Answer: C7
Explanation:A C7 spinal nerve controls elbow extension and some finger extension.
Damage to this nerve can result in a burning pain in the shoulder blade or back of the arms. The ability to extend shoulders, arms, and fingers may also be affected. Dexterity may also be compromised in the hands or fingers.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 14
Correct
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A 6-year-old child with a few itchy honey crusted sores on her left cheek is brought in by her mother. Following a thorough examination of the child, you diagnose impetigo and recommend a course of topical fusidic acid.
Fusidic acid's mode of action is which of the following?Your Answer: Inhibition of protein synthesis
Explanation:By binding EF-G-GDP, fusidic acid prevents both peptide translocation and ribosome disassembly, which slows protein synthesis. Because it has a novel structure and mechanism of action, it is unlikely to cause cross-resistance with existing antibiotics.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 15
Correct
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Which of the following does NOT predispose to digoxin toxicity in a patient taking digoxin:
Your Answer: Hyponatraemia
Explanation:Hypoxia, hypercalcaemia, hypokalaemia and hypomagnesaemia predispose to digoxin toxicity. Care should also be taken in the elderly who are particularly susceptible to digoxin toxicity. Hypokalaemia may be precipitated by use of diuretics. Although hyponatremia can result in the development of other pathological disturbances, it does not potentiate digoxin toxicity.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 16
Incorrect
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Regarding fluid balance, which of the following statements is CORRECT:
Your Answer: The fluid compartments of the body are separated by freely permeable membranes.
Correct Answer: About three-quarters of extracellular fluid is interstitial.
Explanation:An ‘average’ person (70 kg male) contains about 40 litres of water in total, separated into different fluid compartments by biological semipermeable membranes; plasma cell membranes between extracellular and intracellular fluid, and capillary walls between interstitial and intravascular fluid. Around two-thirds of the total fluid (27 L) is intracellular fluid (ICF) and one-third of this (13 L) is extracellular fluid (ECF). The ECF can be further divided into intravascular fluid (3.5 L) and interstitial fluid (9.5 L).
Transcellular fluid refers to any fluid that does not contribute to any of the main compartments but which are derived from them e.g. gastrointestinal secretions and cerebrospinal fluid, and has a collective volume of approximately 2 L.
Osmosis is the passive movement of water across a semipermeable membrane from regions of low solute concentration to those of higher solute concentration. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 17
Correct
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Platelet alpha granules release which of the following?
Your Answer: Von Willebrand factor (VWF)
Explanation:There are three types of storage granules contained in platelets. These are dense granules which contain the following:
-ATP
-ADP
-serotonin and calcium alpha granules containing clotting factors
-von Willebrand factor (VWF)
-platelet-derived growth factor (PDGF)
– other proteins lysosomes containing hydrolytic enzymes. -
This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 18
Incorrect
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Which of the following is the most potent stimulus of fibrinolysis:
Your Answer: Antithrombin
Correct Answer: Tissue plasminogen activator
Explanation:Fibrinolysis is a normal haemostatic response to vascular injury. Plasminogen, a proenzyme in blood and tissue fluid, is converted to plasmin by activators either from the vessel wall (intrinsic activation) or from the tissues (extrinsic activation). The most important route follows the release of tissue plasminogen activator (TPA) from endothelial cells.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 19
Correct
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Which of the following statements accurately describes the flexor digitorum superficialis muscle?
Your Answer: It flexes the middle phalanges of the medial four fingers at the proximal interphalangeal joints
Explanation:Flexor digitorum superficialis is the largest muscle of the anterior compartment of the forearm. It belongs to the superficial flexors of the forearm, together with pronator teres, flexor carpi radialis, flexor carpi ulnaris and palmaris longus. Some sources alternatively classify this muscle as an independent middle/intermediate layer of the anterior forearm, found between the superficial and deep groups.
Flexor digitorum superficialis is innervated by muscular branches of the median nerve, derived from roots C8 and T1 that arises from the medial and lateral cords of the brachial plexus. The skin that overlies the muscle is supplied by roots C6-8 and T1.
The primary arterial blood supply to the flexor digitorum superficialis is derived from the ulnar artery and its anterior recurrent branch. In addition to branches of the ulnar artery, the anterior and lateral surfaces of the muscle are supplied by branches of the radial artery; and its posterior surface also receives branches from the median artery.
The main function of flexor digitorum superficialis is flexion of the digits 2-5 at the proximal interphalangeal and metacarpophalangeal joints. Unlike the flexor digitorum profundus, flexor digitorum superficialis has independent muscle slips for all four digits. This allows it to flex the digits individually at their proximal interphalangeal joints. In addition, flexor digitorum superficialis aids the aids flexion of the wrist.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Correct
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A 69-year-old man presents with a painful groin swelling on the right side. The suspected diagnosis is an inguinal hernia.
Which of the following examination features make it more likely to be an indirect inguinal hernia?Your Answer: It can be controlled by pressure over the deep inguinal ring
Explanation:The reduced indirect inguinal hernia can be controlled by pressure over the internal ring; a direct inguinal hernia cannot.
An indirect inguinal hernia can be reduced superiorly then superolaterally, while a direct inguinal hernia can be reduced superiorly then posteriorly.
An indirect inguinal hernia takes time to reach full size, but a direct inguinal hernia appears immediately upon standing.
Indirect inguinal hernias are seen as elliptical swelling, while direct inguinal hernias appear as symmetric, circular swelling.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 21
Correct
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You're a member of the cardiac arrest team, and you're helping to resuscitate an elderly gentleman who had collapsed at home. The team leader requests that you administer an adrenaline shot.
Which of the following statements about adrenaline is FALSE?Your Answer: The IM dose in anaphylaxis is 1 ml of 1:1000
Explanation:Adrenaline (epinephrine) is a sympathomimetic amine that binds to alpha- and beta-adrenergic receptors and acts as an agonist. It is active at both alpha and beta receptors in roughly equal amounts.
When taken orally, it becomes inactive. Subcutaneous absorption is slower than intramuscular absorption. In cardiac arrest, it is well absorbed from the tracheal mucosa and can be given through an endotracheal tube.
At the adrenergic synapse, catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) metabolise it primarily. The inactive products are then passed through the kidneys and excreted in the urine.
In adult cardiac arrest, the IV dose is 1 mg, which is equal to 10 ml of 1:10000 or 1 ml of 1:1000. In anaphylaxis, the IM dose is 0.5 ml of 1:1000. (500 mcg).
In open-angle glaucoma, adrenaline causes mydriasis and lowers pressure.
Adrenaline is used in cardiopulmonary resuscitation, the treatment of severe croup, and the emergency management of acute allergic and anaphylactic reactions (as a nebuliser solution).
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 22
Correct
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An analytical study is conducted to compare the risk of stroke between Ticagrelor therapy and Warfarin therapy among patients with atrial fibrillation. The following is obtained from the study:
No. of patients who took Ticagrelor: 300
No. of patients who took Ticagrelor and suffered a stroke: 30
No. of patients who took Warfarin: 500
No. of patients who took Warfarin and suffered a stroke: 20
Compute for the absolute risk in the Ticagrelor group.Your Answer: 0.1
Explanation:The absolute risk (AR) is the probability or chance of an event. It is computed as the number of events in treated or control groups, divided by the number of people in that group.
AR = 30/300 = 0.1
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This question is part of the following fields:
- Evidence Based Medicine
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Question 23
Correct
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A 30-year-old man presents with diarrhoea, fever, vomiting, and abdominal cramps. A stool culture was ordered and showed growth of Salmonella spp.
Among the following serotypes of Salmonella spp., which is considered to be the most common cause of salmonella gastroenteritis?Your Answer: Serotype D
Explanation:A common cause of gastroenteritis, Salmonella enteritidis, and Salmonella typhi, which causes enteric fever, are both group D. Therefore, serotype D Salmonella species are most commonly associated with gastroenteritis.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 24
Correct
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All of the following statements are considered true regarding likelihood ratios, except:
Your Answer: If less than one, indicates that the information increases the likelihood of the suspected diagnosis
Explanation:The Likelihood Ratio (LR) is the likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder.
The LR is used to assess how good a diagnostic test is and to help in selecting an appropriate diagnostic tests or sequence of tests. They have advantages over sensitivity and specificity because they are less likely to change with the prevalence of the disorder, they can be calculated for several levels of the symptom/sign or test, they can be used to combine the results of multiple diagnostic test and they can be used to calculate post-test probability for a target disorder.
A LR greater than 1 produces a post-test probability which is higher than the pre-test probability. An LR less than 1 produces a post-test probability which is lower than the pre-test probability. When the pre-test probability lies between 30 and 70 per cent, test results with a very high LR (say, above 10) rule in disease. An LR below 1 produces a post-test probability les than the pre-test probability. A very low LR (say, below 0.1) virtually rules out the chance that the patient has the disease.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 25
Correct
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Which of the following clinical features is NOT typical of a facial nerve palsy:
Your Answer: Inability to raise the eyelid
Explanation:Facial nerve palsy can result in inability to close the eye due to paralysis of the orbicularis oculi muscle. Elevation of the eyelid in eye opening is a function of the levator palpebrae superioris muscle and the superior tarsal muscle, innervated by the oculomotor nerve and the sympathetic chain respectively.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 26
Correct
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What is the approximate lifespan of the mature erythrocyte:
Your Answer: 120 days
Explanation:Erythrocytes have a normal lifespan of about 120 days. Mature erythrocytes are biconcave discs with no nucleus, ribosomes or mitochondria but with the ability to generate energy as ATP by the anaerobic glycolytic pathway. The red cell membrane consists of a bipolar lipid layer with a membrane skeleton of penetrating and integral proteins anchoring carbohydrate surface antigens. The shape and flexibility of red cells allows them to deform easily and pass through capillaries.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 27
Correct
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A 70-year-old patient develops bacteraemia following peripheral cannulation.
Which of these bacteria is the most likely cause of the infection?Your Answer: Staphylococcus epidermidis
Explanation:The commonest implicated organisms in hospital-acquired bacteraemia following cannulation are Staphylococcus aureus and Staphylococcus epidermidis.
The risk is directly proportional to the length of time in-situ. Peripheral cannula should be replaced after 48 hours. -
This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 28
Correct
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A 20-year-old male patient lives in a travelling community and has never received any vaccinations. He presents to you with fever.
Which of these statements concerning indications and contraindications for vaccination is TRUE?
Your Answer: Inactivated vaccines are safe in pregnancy
Explanation:All vaccines are contraindicated in individuals with: A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.
A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinThere is no evidence that vaccinating pregnant women with inactivated vaccine or toxoids harms the woman or foetus.
The current protocol is that a child with history of egg allergy can be safely vaccinated with Fluenz tetra. However, if they had a previous severe anaphylaxis to egg requiring intensive care, then Flenz tetra is contraindicated.
BCG, yellow fever or oral typhoid vaccinations are not safe in HIV positive patients.
The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should not be implemented.
Concurrent antibiotic therapy is not a contraindication to vaccination.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 29
Correct
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At rest, skeletal muscle accounts for between 15-20% of cardiac output and accounts for around 50% of body weight. This can increase to nearly 80% of cardiac output during exercise. Skeletal muscle circulation is highly controlled and has a number of specialized adaptations as a result of this high degree of disparity during exercise, in combination with the diversity in the size of skeletal muscle around the body.
What is the primary mechanism for boosting skeletal muscle blood flow during exercise?
Your Answer: Metabolic hyperaemia
Explanation:In skeletal muscle, blood flow is closely related to metabolic rate. Due to the contraction of precapillary sphincters, most capillaries are blocked off from the rest of the circulation at rest and are not perfused. This causes an increase in vascular tone and vessel constriction. As metabolic activity rises, this develops redundancy in the system, allowing it to cope with greater demand. During exercise, metabolic hyperaemia, which is induced by the release of K+, CO2, and adenosine, recruits capillaries. Sympathetic vasoconstriction in the active muscles is overridden by this. Simultaneously, blood flow in non-working muscles is restricted, preserving cardiac output. During exercise, muscle contractions pump blood through the venous system, raising the pressure differential between arterioles and venules and boosting blood flow via capillaries.
Capillary angiogenesis is evident when muscles are used repeatedly (e.g. endurance training). It is a long-term effect, not a quick fix for increased blood flow.
The local partial pressure of alveolar oxygen is the primary intrinsic control of pulmonary blood flow (pAO2). Low pAO2 promotes arteriole vasoconstriction and vice versa. The hypoxic pulmonary vasoconstriction (HPV) reflex allows blood flow to be diverted away from poorly ventilated alveoli and towards well-ventilated alveoli in order to maximize gaseous exchange.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 30
Incorrect
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Parathyroid hormone is released by which of the following:
Your Answer:
Correct Answer: Chief cells of the parathyroid gland
Explanation:Parathyroid hormone (PTH) is a peptide hormone synthesised by the chief cells of the parathyroid glands, located immediately behind the thyroid gland. PTH is primarily released in response to decreasing plasma [Ca2+] concentration. PTH acts to increase plasma calcium levels and decrease plasma phosphate levels.
Parathyroid hormone (PTH) acts to increase calcium reabsorption in the distal tubule of the nephron (by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane) and increase phosphate excretion by inhibiting reabsorption in the proximal tubule of the nephron. -
This question is part of the following fields:
- Endocrine
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
