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Question 1
Incorrect
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Which one of the following features is least recognised in long-term lithium use?
Your Answer: Goitre
Correct Answer: Alopecia
Explanation:All the above side-effects, with the exception of alopecia, may be seen in patients taking lithium.Common lithium side effects may include:- dizziness, drowsiness;- tremors in your hands;- trouble walking;- dry mouth, increased thirst or urination;- nausea, vomiting, loss of appetite, stomach pain;- cold feeling or discoloration in your fingers or toes;- rash; or.- blurred vision.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 2
Correct
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A 22-year-old university student is admitted after taking drugs at a night club. Which of the following features suggest she had taken ecstasy (MDMA)?
Your Answer: A pyrexia of 40°C
Explanation:MDMA commonly known as ecstasy or molly, is a psychoactive drug primarily used as a recreational drug. The desired effects include altered sensations, increased energy, empathy, and pleasure. Features of MDMA abuse include hyponatraemia, tachycardia, hyperventilation, and hyperthermia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 3
Correct
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Emulsification of dietary lipids is brought about by
Your Answer: Bile salts
Explanation:Digestion of fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 4
Correct
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Select the CORRECT statement regarding bile salts…
Your Answer: Are necessary for any bile acid secretion by hepatocytes.
Explanation:Bile salts stimulate bile secretion by the liver. Bile salts do not have an enzymatic action on digestion of fat but rather emulsify fat for the action of enzymes secreted mainly by the pancreas. Bile salts are polar cholesterol derivatives and are not derived from amino acids.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 5
Correct
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A 31 year old female complains of bilateral proximal muscle weakness. There is marked blanching of fingers especially in response to cold weather. Lab results are as follows: Anti Jo-1: positive ANA: positiveCK: 2000 U/LESR: 60mm/hrEMG: myopathic changesPresence of which of the following signifies the worst prognosis?
Your Answer: Interstitial lung disease
Explanation:Polymyositis is an inflammatory disorder causing symmetrical, proximal muscle weakness. It is thought to be a T-cell mediated cytotoxic process directed against muscle fibres. It may be idiopathic or associated with connective tissue disorders. It may also be associated with malignancy for example small cell lung carcinoma.Dermatomyositis is a variant of the disease where skin manifestations are prominent, for example a purple (heliotrope) rash on the cheeks and eyelids.It typically affects middle-aged, female: male 3:1. Features include proximal muscle weakness +/- tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease: e.g. fibrosing alveolitis or organising pneumonia, dysphagia, dysphonia. Investigations: elevated creatine kinase, other muscle enzymes (lactate dehydrogenase (LD), aldolase, AST and ALT) are also elevated in 85-95% of patients, EMG, muscle biopsy. Anti-Jo-1 antibodies are seen in pattern of disease associated with lung involvement, Raynaud’s and fever. Interstitial lung disease plays a major role in morbidity and mortality in patients with polymyositis and is considered a major risk factor for premature death in patients with myositis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 6
Correct
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A 32 year old man presents with blistering and hyperpigmentation on his face and hands, after a beach holiday with friends. Tests reveal high levels of uroporphyrinogen in the urine. The most likely diagnosis is:
Your Answer: Porphyria cutanea tarda
Explanation:Porphyria cutanea tarda (PCT) is the most common of the porphyries. It is characterised by fragility and blistering of exposed skin. Typically, patients who are ultimately diagnosed with PCT first seek treatment following the development photosensitivities in the form of blisters and erosions on commonly exposed areas of the skin. This is usually observed in the face, hands, forearms, and lower legs. It heals slowly and with scarring. Though blisters are the most common skin manifestations of PCT, other skin manifestations like hyperpigmentation (as if they are getting a tan) and hypertrichosis (mainly on top of the cheeks) also occur. Risk factors for the development of PCT include alcohol and sun.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 7
Correct
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Which of the following portocaval anastomoses can cause problems in preterm infants?
Your Answer: Patent ductus venosus.
Explanation:The ductus venosus is open at the time of the birth and closes during the first week of life in most full-term neonates; however, it may take much longer to close in pre-term neonates. After it closes, the remnant is known as ligamentum venosum. If the ductus venosus fails to occlude after birth, it remains patent (open), and the individual is said to have a patent ductus venosus and thus an intrahepatic portosystemic shunt (PSS).
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 8
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 9
Correct
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The spinothalamic tracts are particularly concerned with:
Your Answer: Pain and temperature sensations
Explanation:The spinothalamic tracts are part of the anterolateral system in the spinal cord and are responsible for transmitting sensory information related to pain, temperature, and crude touch from the peripheral nervous system to the thalamus in the brain. This sensory information is then relayed to the cerebral cortex for processing. The spinothalamic tracts are divided into two main pathways:
- Lateral spinothalamic tract: Transmits pain and temperature sensations.
- Anterior spinothalamic tract: Transmits crude touch and pressure sensations.
Control of posture: The reticulospinal and vestibulospinal tracts are primarily involved in the control of posture and balance. These tracts originate in the brainstem and help maintain posture by influencing the motor neurons that control axial and proximal muscles.
Voluntary skilled movements: The corticospinal tracts (also known as the pyramidal tracts) are responsible for voluntary skilled movements. These tracts originate in the motor cortex and descend through the brainstem and spinal cord to synapse on motor neurons that control fine motor movements, especially of the distal limbs.
Muscular tone: Muscular tone is primarily regulated by several tracts, including the reticulospinal and vestibulospinal tracts. Additionally, the rubrospinal tract (originating from the red nucleus in the midbrain) also contributes to motor control and muscle tone, particularly of the upper limbs.
Visual input: The optic tracts and pathways (including the optic nerve, optic chiasm, optic tract, lateral geniculate nucleus, and optic radiations) are responsible for transmitting visual information from the retina to the primary visual cortex in the occipital lobe. This pathway processes visual input, including aspects such as color, motion, and depth perception.
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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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Which of the following is true of the Natriuretic hormones?
Your Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 11
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 12
Incorrect
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Which one of the following cells originates from a monocyte and resembles a macrophage?
Your Answer: Astrocyte
Correct Answer: Microglia
Explanation:Microglia act as the macrophages of the central nervous system, and they contribute to innate and adaptive immune responses. Studies have shown that microglial cells recognize monocyte antigens, and there are similarities between them that demonstrate that they originate from these monocytes.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 13
Correct
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Which of the following happens when anterograde neurons are stimulated?
Your Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Correct
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HCL is secreted by which cells in the stomach
Your Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 15
Correct
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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 16
Incorrect
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The actions of thrombin result directly in the release of:
Your Answer: 3 pairs of polypeptides from each fibrinogen molecule
Correct Answer: Fibrin monomers
Explanation:Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 17
Correct
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Where is retinol mainly stored?
Your Answer: Liver
Explanation:Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably beta-carotene). The liver stores a multitude of substances, including glucose (in the form of glycogen), vitamin A (1–2 years’ supply), vitamin D (1–4 months’ supply), vitamin B12 (3–5 years’ supply), vitamin K, iron, and copper.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 18
Correct
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A 56-year-old male presents to the emergency department with confusion and agitation for the past four hours. He is a known alcoholic who has abstained from drinking for the past three days.On examination, he is sweating, agitated and disorientated. His temperature is 37.7°C, pulse 112 bpm regular and blood pressure is 150/76 mmHg. Blood investigations performed in the emergency department reveal:FBC: NormalU&E: NormalPlasma glucose: 4.6 mmol/l (3.6-6)Which of the following medications would be the most appropriate treatment for this man?
Your Answer: Oral lorazepam
Explanation:The most probable diagnosis for this patient is delirium tremens due to alcohol withdrawal, which should be treated as a medical emergency. Delirium tremens is a hyperadrenergic state and is often associated with tachycardia, hyperthermia, hypertension, tachypnoea, tremor, and mydriasis.Treatment:- The most common and validated treatment for alcohol withdrawal is benzodiazepine: first-line treatment includes oral lorazepam. – If the symptoms persist, or the medication is refused, parenteral lorazepam, haloperidol or olanzapine should be given.- Central-acting, alpha-2 agonists such as clonidine and dexmedetomidine should not be used alone for the treatment of alcohol withdrawal.- It is also recommended to avoid using alcohol, antipsychotics, anticonvulsants, beta-adrenergic receptor blockers, and baclofen for the treatment of alcohol withdrawal as there are not enough studies to support the safety of these.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 19
Correct
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Although variable, branches of which artery most often supply the SA and AV nodes?
Your Answer: Right coronary artery
Explanation:The RCA (right coronary artery) supplies the SA and the AV nodes along with the postero-basal wall of the left ventricle, posterior one third of the inferior vena cava, right ventricle and the posteromedial papillary muscle in the left ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Correct
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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 21
Correct
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Regarding carbohydrates absorption;
Your Answer: Intestinal absorption of sugars is inhibited by the drug phlorizin
Explanation:The main role of insulin is in the uptake of glucose from blood to tissues where it is metabolised. Glycose transporters in the intestines do not depend on the action of insulin. Phlorizin is a competitive inhibitor of SGLT1 and SGLT2 because it competes with glucose for the binding site, reducing intestinal and renal glucose transport.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 22
Incorrect
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Salty taste is triggered by:
Your Answer: Heterotrimeric g-protein, gustducon
Correct Answer: Amiloride-sensitive sodium channel
Explanation:Amiloride-sensitive sodium channels also known as epithelial Na channels is a membrane bound ion channel that is selectively permeable to Na+ ions. These channels are located throughout different epithelial membranes in the body. It is found in taste receptor cells, where it plays an important role in salt taste perception. They are also located in the kidney, the lung and the colon. Hyperpolarization-activated, cyclic nucleotide-gated (HCN) voltage-gated ion channels are widely seen in the cortex, hippocampus, thalamus and brain regions that underlie the generation of both focal and generalized-onset seizures. The metabotropic glutamate receptor (mGluRs) perform a variety of functions in the central and peripheral nervous systems. They are involved in learning, memory, anxiety, and the perception of pain. Gustducin is a G protein associated with taste and gustatory system. It plays a major role in sensation of bitter, sweet and umami stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 23
Correct
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The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 24
Incorrect
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What is the function of the acute phase protein, C-reactive protein?
Your Answer: Activates complement
Correct Answer: Opsonises bacteria
Explanation:There are various immune reactions that become activated once the barrier between the body and environment has been compromised. There are certain opsonins that bind to the bacteria and facilitate phagocytosis. One of them is the acute phase protein: C protein. others include antibodies and complement.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 25
Correct
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Where is intrinsic factor secreted?
Your Answer: Gastric parietal cells
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:
- Haematology
- Medicine
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Question 26
Correct
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The steps of cardiac cycle in sequence are:
Your Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.1st stage: diastole, or passive filling is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th stage: isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 27
Incorrect
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Which one of the following antibiotics is safest to use in pregnancy?
Your Answer: Clarithromycin
Correct Answer: Erythromycin
Explanation:Antibiotics that should be avoided in pregnancy are included in the mnemonic: Countless SAFe Moms Take Really Good Care -Clarithromycin, Sulphonamides, Aminoglycosides, Fluoroquinolones, Metronidazole, Tetracyclines, Ribavirin, Griseofulvin, Chloramphenicol
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 28
Correct
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Neutrophils are attracted to an infected area by:
Your Answer: Chemokines
Explanation:The major role of chemokines is to act as a chemoattractant to guide the migration of cells like neutrophils to the site of infection.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 29
Correct
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Which of the following factors is directly responsible for the breakdown of fibrinogen to fibrin?
Your Answer: Thrombin
Explanation:Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 30
Correct
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The sympathetic supply to the stomach comes from the:
Your Answer: Celiac plexus
Explanation:The vagus nerve supplies the stomach and up to proximal two-thirds of the large intestine and has parasympathetic stimulation. The sympathetic chain which begins at the level of he 1st thoracic vertebra and extends up to 3rd lumbar vertebra gives off the celiac plexus which mainly supplies the stomach. The mesenteric plexus mainly supplies the small intestine and is located below the celiac plexus in the sympathetic chain.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 31
Correct
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A 26 year old male presents with right sided elbow and wrist pain and left sided knee and ankle pain that has persisted for about two weeks. He recently returned from a trip to Thailand that last for two weeks. The patient admits to having unprotected sex while on holiday. Examination reveals swelling and tenderness of tendons around joints but no inflammation of the joints. A vesiculopustular skin rash is also observed. What is the most likely cause?
Your Answer: Gonococcal arthritis
Explanation:Patients with disseminated gonococcal arthritis may present with dermatitis-arthritis syndrome (60%) of with localized septic arthritis. (40%). Arthritis-dermatitis syndrome includes the classic triad of dermatitis, tenosynovitis, and migratory polyarthritis. Gout usually involves a singe joint and does not cause vesicopustular skin rash. Reactive arthritis has ocular symptoms (conjunctivitis), urethritis, and arthritis. Fungal arthritis occurs rarely and it may occur after a surgical infection or fungal spread hematogenously. it presents with tender, red, hot and swollen joint with loss of range of motion.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 32
Correct
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Question 33
Correct
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The channel that coalesces the small pancreatic duct radicles before joining the common bile duct is known as the:
Your Answer: Duct of Wirsung
Explanation:The small ducts from the pancreas coalesce into a single duct known as the pancreatic duct or the duct of Wirsung. It usually joins the bile duct at the ampulla of Vater before entering the duodenum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 34
Correct
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A 16 year old previously well male presents with a 4 day history of fever, lethargy and a generalized macular rash. There is no significant previous medical history and the patient has not travelled abroad either. Vitals are as follows: Temp: 38.5BP: 125/75mmHgPulse: 100/min On auscultation the chest was clear and no heart murmur was heard. Examination also reveals a non blanching widespread macular rash over the chest and abdomen. There is swelling of interphalangeal joints of both hands and feet associated with mild tenderness. Lymph nodes are palpable over the supraclavicular, axillary and inguinal areas. Abdominal examination reveals palpable mass on both right and left hypochondrium. Lab results are given below:Haemoglobin (Hb) 13.5 g/dlWhite cell count (WCC) 14.0 × 109/lPlatelets 380 × 109/lSodium 145 mmol/lPotassium 4.8 mmol/lCreatinine 89 μmol/lRheumatoid factor NegativeAntinuclear antibody NegativeAnti-dsDNA NegativeASO titre Not detectedElectrocardiogram (ECG) Sinus rhythmWhat is the most likely underlying diagnosis?
Your Answer: Systemic Still’s disease
Explanation:People with Systemic Juvenile Idiopathic Arthritis (also known as Stills disease) can have recurrent fevers, a macular rash, joint pain, joint deformities, an enlarged liver and/or spleen, and can occasionally have polyserositis, lung involvement or pericardial effusions. Rheumatoid factor and antinuclear antibodies are usually negative. Treatment is with non-steroidal anti-inflammatory drugs (NSAIDs) and the prognosis is better than for adult rheumatoid arthritis.In pauciarticular Still’s disease, antinuclear antibodies are present. Large joints are affected and most patients develop classic features of seronegative spondylarthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 35
Incorrect
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A 26-year-old student has been brought to the emergency department in a confused state. His friends report that he has been complaining of headaches for the past few weeks. He has a low-grade fever and on examination is noted to have abnormally pink mucosa. What is the most likely diagnosis?
Your Answer: Meningitis
Correct Answer: Carbon monoxide poisoning
Explanation:Confusion and pink mucosae are typical features of CO poisoning.The patient often presents, most commonly with headaches, and other symptoms like malaise, nausea, and dizziness.Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Features of carbon monoxide toxicity- Headache: 90% of cases- Nausea and vomiting: 50%- Vertigo: 50%- Confusion: 30%- Subjective weakness: 20%- Severe toxicity: ‘pink’ skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, deathTreatment:Use of Hyperbaric oxygen therapy (HBOT) for treating mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 36
Correct
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Which of the following enzymes is mainly responsible for the hydrolysis of polysaccharide 1:6a linkages?
Your Answer: Isomaltase
Explanation:Isomaltase is mainly responsible for hydrolysis of 1:6α linkages. Along with maltase and sucrase, it also breaks down maltotriose and maltose.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 37
Correct
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A case-control study is being designed to look at the relationship between eczema and a new vaccine for yellow fever. What is the usual outcome measure in a case-control study?
Your Answer: Odds ratio
Explanation:A case–control study (also known as case–referent study) is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case–control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the cases) with patients who do not have the condition/disease but are otherwise similar (the controls).An odds ratio (OR) is a statistic that quantifies the strength of the association between two events, A and B. The odds ratio is defined as the ratio of the odds of A in the presence of B and the odds of A in the absence of B or vice versa.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 38
Incorrect
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Which of the following is NOT associated with the development of aortic regurgitation?
Your Answer: Ankylosing spondylitis
Correct Answer: Dilated cardiomyopathy
Explanation:Aortic insufficiency, is often due to the aortic root dilation, which is idiopathic in over 80% of cases, but otherwise may result from aging, syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Bechet’s disease, reactive arthritis and systemic hypertension. Additionally, aortic insufficiency has been linked to the use of some medications and other potential causes that affect the valve directly including Marfan’s syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, and systemic lupus erythematosus. In acute cases of aortic insufficiency, the main causes are infective endocarditis, aortic dissection or trauma. Dilated cardiomyopathy is associated with the development of mitral regurgitation, not aortic regurgitation
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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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An 82 year old man arrives at the clinic with painful right upper arm that he has been experiencing for the last few months. The pain is gradually worsening and often wakes him up at night. He is a known case of Paget's disease involving his lumbar spine and pelvis and is currently taking oral bisphosphonates. On examination, shoulder movements are intact. Which of the following is the most likely cause of his arm pain?
Your Answer: Osteosarcoma
Explanation:Paget’s accelerates the remodelling process with old bone breaking down more quickly which disrupts the normal growth process. New bone development eventually adjusts to the faster pace and speeds up on its own. The pace is too fast for healthy bone growth, and the regrowth ends up softer and weaker than normal. The effect of this accelerated process causes bone pain, fractures, and deformities. Since osteosarcoma is a type of bone cancer linked to abnormal bone growth, this makes it a rare but possible complication of Paget’s disease although the chances of developing osteosarcoma are minimal. Fractures are painful and restrict movement whereas this patients pain is gradually developing. Pain associated with osteoarthritis is usually mild to moderate and worsens as the day progresses.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 40
Correct
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The a-wave is created by:
Your Answer: Regurgitation of some blood to the great veins when the atria contracts in atrial systole
Explanation:The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 41
Incorrect
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A 50-year-old man with a history of hyperlipidaemia, currently under treatment with simvastatin 10mg was found to have persistently high cholesterol levels. Previous attempts to increase the dose of simvastatin have resulted in myalgia. Given this history, which one of the following lipid-regulating drugs should definitely be avoided?
Your Answer: Nicotinic acid
Correct Answer: Bezafibrate
Explanation:Both fibrates and nicotinic acid have been associated with myositis, especially when combined with a statin. However, the Committee on Safety of Medicines has produced guidance which specifically warns about the concomitant prescription of fibrates with statins concerning muscle toxicity.Bezafibrate: It is a fibric acid derivative (fibrate) that has been used as a class of agents known to decrease triglyceride levels while substantially increasing HDL-C levels.Pharmacological effects:- Increases VLDL catabolism by increasing lipoprotein and hepatic triglyceride lipase.- Decreases triglyceride synthesis by inhibiting acetyl-CoA reductase.- Decreases cholesterol synthesis by inhibiting HMG-CoA reductase.Side effects:- Hypersensitivity- Primary biliary cirrhosis- Pre-existing gallbladder disease- Concurrent use with HMG-CoA inhibitors (statins) can produce myopathy- Hepatic/renal impairment in a patient warrants dose adjustment as this drug is primarily excreted via the renal mechanism.Contraindications: Concurrent use of MAO inhibitors, hypersensitivity, pre-existing cholestasis, and pregnancy.Use: It can be used to treat Barth syndrome (characterized by dilated cardiomyopathy, neutropenia (presenting with recurrent infections), skeletal myopathy and short stature)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 42
Correct
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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 43
Correct
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Which of the following is a characteristic clinical finding of opioid poisoning?
Your Answer: Bradycardia
Explanation:Opioid poisoning is classically associated with pinpoint pupils, reduced respiratory rate, bradycardia, drowsiness and coma. Hypothermia is a feature of barbiturate poisoning, while sweating and lacrimation are seen in cases of opiate withdrawal.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 44
Correct
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Which of the following statements regarding influenza virus is correct?
Your Answer: Influenza is a RNA virus
Explanation:The Orthomyxoviruses are a family of RNA viruses that includes six genera: Influenza virus A, Influenza virus B, Influenza virus C, Isavirus, Thogotovirus and Quaranjavirus.The mechanism of the evolutionary force of antigenic shift allows influenza viruses to exchange genes with strains that infect different species. Under this mechanism, a human influenza virus could exchange genes with an avian strain, and that is how pandemic strains arise.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 45
Correct
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Which statement is incorrect?
Your Answer: Translation begins when the triplet (UGA) encoding for methionine is encountered.
Explanation:Translation being when the codon for methionine is encountered which is AUG not UGA. This process is known as initiation. All the other options are correct.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 46
Correct
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The action of progesterone on different organs/systems includes:
Your Answer: Breasts: stimulation of lobular and alveolar development
Explanation:Progesterone is a sex hormone which affects mainly the reproductive system. In the breasts, it mediates the lobuloalveolar maturation to allow for milk production; this is done in conjunction with prolactin. It acts to maintain female reproductive and sex characteristics.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 47
Correct
-
The infoldings or spaces between the bases of the villi are known as
Your Answer: Crypts of Lieberkühn
Explanation:An intestinal gland (also crypt of Lieberkühn and intestinal crypt) is a gland found in the intestinal epithelium lining of the small intestine and large intestine (colon) between the villi.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 48
Incorrect
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Myocardial oxygen consumption is increased by:
Your Answer: By additional oxygen extraction from blood
Correct 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 49
Correct
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Question 50
Correct
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Where is leptin synthesized and secreted?
Your Answer: White adipose tissue
Explanation:Leptin is a hormone that helps regulate food intake and energy expenditure. It is synthetized by white adipose tissue and the gastric mucosa. It works by inhibiting the sensation of hunger, therefore, it opposes the actions of ghrelin, also known as the hunger hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 51
Correct
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Which of the following normally has a slow depolarizing “prepotential”?
Your Answer: Sinoatrial node
Explanation:There are 2 main types of action potentials (AP) in the heart, the slow response and the fast response:The slow response is initiated by the slow calcium-sodium channels, found in the SA node (which is the natural pacemaker of the heart) and the conduction fibers of the AV node.The fast response occurs in the atrial and ventricles muscle cells and the purkinje fibers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 52
Incorrect
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A 28 year old man presents to the clinic with fatigue, exertional dyspnoea, abdominal discomfort, xerophthalmia and xerostomia. Examination reveals enlargement of the parotid glands bilaterally, hepatomegaly and peripheral motor neuropathy. Lab results are negative for RF, ANA, SS-A and SS-B antibodies. What is the most likely diagnosis?
Your Answer: Sjogren's syndrome
Correct Answer: Diffuse infiltrative lymphocytic syndrome (DILS)
Explanation:The Diffuse Infiltrative Lymphocytosis Syndrome (DILS) is a rare multisystemic syndrome described in HIV-infected patients. It is characterised by CD8(+) T-cell lymphocytosis associated with a CD8(+) T-cell infiltration of multiple organs. DILS is usually seen in uncontrolled or untreated HIV infection but can also manifest itself independently of CD4(+) T-cell counts. The syndrome may present as a Sjögren-like disease that generally associates sicca signs with bilateral parotiditis, lymphadenopathy, and extra glandular organ involvement. The latter may affect the lungs, nervous system, liver, kidneys, and digestive tract. Anomalies of the respiratory system are often identified as lymphocytic interstitial pneumonia. Facial nerve palsy, aseptic meningitis or polyneuropathy are among the more frequent neurological features. Hepatic lymphocytic infiltration, lymphocytic interstitial nephropathy and digestive tract lymphocytic infiltration account for more rarely noted complications. Sicca syndrome, organomegaly and/or organ dysfunction associated with polyclonal CD8(+) T-cell organ-infiltration are greatly suggestive of DILS in people living with HIV.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 53
Incorrect
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Which of the following conditions is NOT X-linked recessive?
Your Answer: Complete testicular feminisation
Correct Answer: Cystic fibrosis
Explanation:Cystic fibrosis is a autosomal recessive disease with an incidence of about 1 in 2500 live births. The most common mutation occurs in the long arm of chromosome 7 which codes for the chloride channel (cystic fibrosis transmembrane conductance regulator) gene.
To have CF, a child must inherit two abnormal genes—one from each parent. The recessive CF gene can occur in both boys and girls because it is located on non-sex-linked chromosomes called autosomal chromosomes.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 54
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 55
Correct
-
Where is Basic Electrical rhythm initiated
Your Answer: Interstitial cells of cajal
Explanation:The interstitial cells of Cajal are specialized pacemaker cells located in the wall of the stomach, small intestine, and large intestine. These cells are connected to the smooth muscle via gap junctions and the myenteric plexus. The cell membranes of the pacemaker cells undergo a rhythmic depolarization and repolarization from -65mV to -45mV. This rhythm of depolarization-repolarization of the cell membrane creates a slow wave known as a basic electrical rhythm (BER), and it is transmitted to the smooth muscle cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 56
Correct
-
Which enzyme deficiency causes Beriberi?
Your Answer: Thiamine
Explanation:Beriberi refers to a cluster of symptoms caused primarily by thiamine (vitamin B1) deficiency. Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 57
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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Question 58
Correct
-
Which coronary artery supplies the right atria?
Your Answer: Right coronary
Explanation:The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 59
Correct
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A 46 year old male, known with Rheumatoid Arthritis presents with a swollen and painful right ankle. No drug allergies are reported. On examination, the vitals are as follows: Temp: 38.8BP: 90/60 mmHgPulse: 110/min. Right ankle examination reveals tenderness, warmth, erythema and tense joint effusion. Blood samples including blood cultures are collected and fluid resuscitation is initiated. Which of the following interventions would be most appropriate for this man?
Your Answer: Administer i.v. flucloxacillin, and arrange joint aspiration urgently
Explanation:Although microscopic analysis of joint fluid aspirate and culture is the basis of septic arthritis diagnosis and should usually be collected before the administration of antibiotics, the patient is showing signs of septic shock. A delay in antibiotics might lead to worsening of symptoms so they are administered first.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 60
Incorrect
-
Telomerase is active in the following cells except:
Your Answer: Certain liver cells
Correct Answer: Certain osteoblasts
Explanation:Some cells have the ability to reverse telomere shortening by expressing telomerase, an enzyme that extends the telomeres of chromosomes. Telomerase is an RNA-dependent DNA polymerase, meaning an enzyme that can make DNA using RNA as a template.
Telomerase is not usually active in most somatic cells (cells of the body), but it’s active in germ cells (the cells that make sperm and eggs) and some adult stem cells. These are cell types that need to undergo many divisions, or, in the case of germ cells, give rise to a new organism with its telomeric “clock” reset.Interestingly, many cancer cells have shortened telomeres, and telomerase is active in these cells. If telomerase could be inhibited by drugs as part of cancer therapy, their excess division (and thus, the growth of the cancerous tumor) could potentially be stopped.A subset of liver cells with high levels of telomerase renews the organ during normal cell turnover and after injury. -
This question is part of the following fields:
- Genetics
- Medicine
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Question 61
Correct
-
Regarding Polymerase Chain Reaction, all are true except:
Your Answer: There is a linear rise of DNA copies during amplification.
Explanation:All are true except there is a linear rise of DNA copies during amplification. There is an exponential rise in amplification of DNA.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 62
Correct
-
Which of the following hormones would stimulate secretion of TSH?
Your Answer: TRH
Explanation:Thyrotropin-releasing hormone, also known as TRH, thyrotropin-releasing factor, TRF is a hormone produced by the hypothalamus. It functions as a releasing hormone, promoting the production of thyroid-stimulating hormone or thyrotropin and prolactin.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 63
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 64
Correct
-
A 22 year old man is being evaluated for chronic lower backache. Which of the following would most strongly point towards the diagnosis of ankylosing spondylitis?
Your Answer: Reduced lateral flexion of the lumbar spine
Explanation:Ankylosing spondylitis (spondylarthritis) is a chronic inflammatory disease of the axial skeleton that leads to partial or even complete fusion and rigidity of the spine. Males are disproportionately affected and upwards of 90% of patients are positive for the HLA-B27 genotype, which predisposes to the disease. The most characteristic early finding is pain and stiffness in the neck and lower back, caused by inflammation of the vertebral column and the sacroiliac joints. The pain typically improves with activity and is especially prominent at night. Other articular findings include tenderness to percussion and displacement of the sacroiliac joints (Mennell’s sign), as well as limited spine mobility, which can progress to restrictive pulmonary disease. The most common extra-articular manifestation is acute, unilateral anterior uveitis. Diagnosis is primarily based on symptoms and x-ray of the sacroiliac joints, with HLA-B27 testing and MRI reserved for inconclusive cases. There is no curative treatment, but regular physiotherapy can slow progression of the disease. Additionally, NSAIDs and/or tumour necrosis factor-α inhibitors may improve symptoms. In severe cases, surgery may be considered to improve quality of life. The spine adopts a bamboo shape, not lordosis. The pain usually improves as the day progresses. leg raise test causes pain in cases of meningitis etc not in this case.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 65
Correct
-
Which pair is correct concerning enteroendocrine cells in the GIT mucosa and their products?
Your Answer: D cells and somatostatin
Explanation:Somatostatin, an inhibitory hormone is secreted form the D cells of the Pancreatic Islets.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 66
Correct
-
During which stage of sleep is muscle tone in the limbs most reduced?
Your Answer: REM
Explanation:Rapid eye movement (REM) stage is marked by extensive physiological changes in the body, such as accelerated respiration, increased brain activity and muscle relaxation. People dream during REM sleep, perhaps as a result of excited brain activity and the paralysis of major voluntary muscles.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 67
Correct
-
The intestine is lined by:
Your Answer: Simple columnar epithelium
Explanation:In the small intestine, epithelium is simple columnar and specialised for absorption. The epithelium is arranged into villi, creating a brush border and increasing the area for absorption. The epithelium is simple columnar with microvilli.In the colon, epithelium is simple columnar and without villi. Goblet cells, which secrete mucous, are also present.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 68
Correct
-
Which one of the following is necessary to activate plasminogen to plasmin?
Your Answer: tPA
Explanation:In circulation, plasminogen adopts a closed, activation resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 69
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 70
Correct
-
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 71
Correct
-
Which of the following is the smallest cell of the nervous system?
Your Answer: Microglia
Explanation:Microglia are the smallest of the neuroglial cells in the nervous system. They are scattered throughout the central nervous system and have phagocytic properties.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 72
Correct
-
In terms of relative steroid potency, how much prednisone is equivalent to 100mg hydrocortisone?
Your Answer: 25mg
Explanation:Different corticosteroids have varying degrees of potency. 1 mg of prednisone is equivalent to 4 mg of hydrocortisone. Therefore, 25 mg of prednisone are equivalent to 100 mg of hydrocortisone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 73
Correct
-
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 74
Correct
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Question 75
Correct
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Question 76
Incorrect
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Xanthines such as caffeine and theophylline are positively inotropic due to:
Your Answer: Circulating catecholamines
Correct Answer: Inhibition of cAMP breakdown
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contractions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 77
Correct
-
Which of the following is NOT a pancreatic enzyme?
Your Answer: Pepsinogen 1
Explanation:Pancreatic juice, composed of the secretions of both ductal and acinar cells, is made up of the following digestive enzymes:Trypsinogen, which is an inactive(zymogenic) protease that, once activated in the duodenum into trypsin, breaks down proteins at the basic amino acids. Trypsinogen is activated via the duodenal enzyme enterokinase into its active form trypsin.Colipase is a protein co-enzyme required for optimal enzyme activity of pancreatic lipase. It is secreted by the pancreas in an inactive form, procolipase, which is activated in the intestinal lumen by trypsin.Chymotrypsinogen, which is an inactive (zymogenic) protease that, once activated by duodenal enterokinase, breaks down proteins at their aromatic amino acids. Chymotrypsinogen can also be activated by trypsin.Carboxypeptidase, which is a protease that takes off the terminal amino acid group from a proteinSeveral elastases that degrade the protein elastin and some other proteins.Pancreatic lipase that degrades triglycerides into fatty acids and glycerol.Sterol esterasePhospholipaseSeveral nucleases that degrade nucleic acids, like DNase and RNase.Pancreatic amylase that breaks down starch and glycogen which are alpha-linked glucose polymers.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 78
Correct
-
What is the average life span of red blood cells?
Your Answer: 4 months
Explanation:Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days (4 months) in the body before their components are recycled by macrophages.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 79
Correct
-
The predominant receptors in the hearts conduction system are?
Your Answer: Β1
Explanation:All of the components of the intrinsic conduction system contain autorhythmic cells that spontaneously depolarize. In the absence of extrinsic neural or hormonal influences, the SA node pacing rate would be about 100 beats per minute (bpm). The heart rate and cardiac output, however, must vary in response to the needs of the body’s cells for oxygen and nutrients under varying conditions. In order to respond rapidly to changing requirements of the body’s tissues, the heart rate and contractility are regulated by the autonomic nervous system (ANS), hormones, and other factors. The ANS has two interacting systems: the sympathetic and parasympathetic systems.
Sympathetic receptors: There are two types of adrenergic receptors: β and α. In the cardiovascular system there are β1, β2, α1, and α2 adrenergic receptors. β1 adrenergic receptors are expressed in the heart conduction system (in the SA node, AV node, and on atrial and ventricular cardiomyocytes). The activation of β1 receptors increases heart rate (via the SA node), and contractility.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 80
Correct
-
Which of the following involving the scalp may produce alopecia (hair loss)?
Your Answer: Discoid lupus erythematosus
Explanation:Causes of hair loss include:
- Dissecting cellulitis
- Fungal infections (such as tinea capitis)
- Folliculitis
- Secondary syphilis
- Demodex folliculorum
- Lupus erythematosus (hair loss may be permanent due to scarring of the hair follicles).
Psoriasis and seborrheic dermatitis commonly involve the scalp but do not produce hair loss.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 81
Correct
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Question 82
Correct
-
Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.
Your Answer: ATP
Explanation:A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 83
Correct
-
Which is true of the composition of bile in the human hepatic duct?
Your Answer: Contains only actively secreted substances
Explanation:Hepatic bile is an isotonic fluid and its electrolyte composition resembles that of plasma. 97% of water is found in the gallbladder bile, not hepatic duct. Hepatic bile is alkaline. The ratio of bile acids: phosphatidylcholine: cholesterol is 20:1:3. Hepatic bile contai9ns only actively secreted substances.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 84
Correct
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Question 85
Correct
-
Which of the following conditions is procoagulant?
Your Answer: Factor V Leiden
Explanation:Factor V Leiden is a genetic mutation of one of the clotting factors in the blood, Factor V. This mutation makes Factor V resistant to inactivation by activated Protein C, which normally helps to regulate clot formation. As a result, individuals with Factor V Leiden are at increased risk of developing abnormal blood clots (thrombophilia), making it a procoagulant condition.
The other conditions listed are associated with bleeding tendencies rather than increased clotting:
- Afibrinogenemia: A rare genetic disorder where there is a complete lack of fibrinogen, leading to bleeding problems.
- Hemophilia: A group of inherited bleeding disorders where blood does not clot properly due to the lack of sufficient blood-clotting proteins (factors VIII or IX).
- Hypothrombinemia: A condition characterized by low levels of prothrombin, leading to increased bleeding.
- Christmas disease (Hemophilia B): A form of hemophilia caused by a deficiency of factor IX, resulting in a bleeding tendency.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 86
Correct
-
Empagliflozin was found to reduce the risk of cardiovascular deaths, non-fatal myocardial infarction and non-fatal stroke when added to standard treatment plans in patients with type 2 diabetes mellitus. This information was shared in 2015 by The New England Journal of Medicine and the results were expressed per 1000 patient years. In fact, empagliflozin had an event rate of 37.3/1000 patient years and placebo an event rate of 43.9/1000 patient years. How many patients who are at high cardiovascular risk need to be treated with empagliflozin to prevent a cardiovascular death, a non-fatal myocardial infarction or a non-fatal stroke?
Your Answer: 150
Explanation:The number needed to treat (NNT) is an absolute effect measure that has been used to assess beneficial and harmful effects of medical interventions. In this case the NNT can be calculated as follows: NNT = 1/ Absolute risk reduction (ARR). ARR=(Control event rate expressed per 1000 patient years) – (Experimental event rate expressed per 1000 patient years) = 43.9-37.3 = 6.6/1000 patient yearsNNT=(Patient years)/ARR = 1000/ 6.6 = 151.5. The closest to 151.5 is 150, thus it is the correct answer.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 87
Correct
-
All of the following constitute small intestinal brush border enzymes except:
Your Answer: Alpha-amylase
Explanation:The final step in digestion of carbohydrates, which is conversion of disaccharides to absorbable monosaccharides occurs on the small intestinal epithelial cells. The enzymes responsible for this final stage of digestion are not freely found in the intestinal lumen, but they are found as integral membrane proteins in the plasma membrane of the epithelial cell. The apical plasma membrane of the intestinal epithelial cell has numerous microvilli which extend from the cell known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes. All these enzymes except alfa amylase are brush border enzymes. Alfa amylase is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 88
Correct
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Question 89
Incorrect
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A 23 year old male presents with a history of lower back pain for the last one year. Presence of which of the following features most likely points towards ankylosing spondylitis?
Your Answer: Presence of HLA-B27 antigen on tissue typing
Correct Answer: Bilateral erosion of sacroiliac joints on X-ray
Explanation:Bilateral erosions of the sacroiliac joints on pelvic radiographs of patients with ankylosing spondylitis are an important feature of the modified New York classification criteria. Although HLA-B27 is commonly associated with AS, it can also be found in normal individuals. Back stiffness is worse in the morning and gets better as the day progresses. Tenderness and limited lumbar motion can be associated with other spine problems as well and is not characteristic of rheumatoid arthritis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 90
Correct
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Question 91
Correct
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Cholecystokinin causes the pancreas to
Your Answer: Produce pancreatic juice rich in enzymes
Explanation:Cholecystokinin (CCK) mediates digestion in the small intestine by inhibiting gastric emptying and decreasing gastric acid secretion. It stimulates the acinar cells of the pancreas to release a juice rich in pancreatic digestive enzymes, hence the old name pancreozymin. Together these enzymes catalyse the digestion of fat, protein, and carbohydrates.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 92
Correct
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In response to tissue injury, which of these cannot sensitize and activate nociceptors?
Your Answer: Calcium
Explanation:Histamine, serotonin, bradykinin and prostaglandin are all chemical mediators of inflammation with different distinct functions however all activate nociceptors. Calcium on the other hand cannot sensitize or activate nociceptors.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 93
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 94
Incorrect
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Which one of the following features is least associated with primary hyperparathyroidism?
Your Answer: Polyuria
Correct Answer: Sensory loss
Explanation:The signs and symptoms of primary hyperparathyroidism are those of hypercalcemia. They are classically summarized by stones, bones, abdominal groans, thrones and psychiatric overtones.
Stones refers to kidney stones, nephrocalcinosis, and diabetes insipidus (polyuria and polydipsia). These can ultimately lead to renal failure.
Bones refers to bone-related complications: osteitis fibrosa cystica, osteoporosis, osteomalacia, and arthritis.
Abdominal groans refers to gastrointestinal symptoms of constipation, indigestion, nausea and vomiting. Hypercalcemia can lead to peptic ulcers and acute pancreatitis.
Thrones refers to polyuria and constipation
Psychiatric overtones refers to effects on the central nervous system. Symptoms include lethargy, fatigue, depression, memory loss, psychosis, ataxia, delirium, and coma.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 95
Correct
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Which of the following stimuli increase growth hormone secretion?
Your Answer: Ghrelin
Explanation:Ghrelin is a hormone which serves as an endogenous ligand for the growth hormone secretagogue receptor. It acts on the pituitary and the hypothalamus by affecting the vagus nerve. It acts on the somatotrophs of the anterior pituitary, GHRH-secreting neurons, and on GHIH-secreting neurons in the hypothalamus, causing a time-dependent and pulsatile stimulation over the secretion of growth hormone.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 96
Correct
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A 73-year-old female is being reviewed in the osteoporosis clinic. She had a fracture of her left hip 5 years ago and was started on alendronate. Following the development of persistent musculoskeletal pain, alendronate was replaced with risedronate, which was also stopped for similar reasons. Strontium ranelate was therefore started but was also stopped due to the development of deep vein thrombosis in the right leg. Her current T-score is -4.1. A decision is made to start a trial of denosumab. What is the mechanism of action of denosumab?
Your Answer: Inhibits RANK ligand, which in turn inhibits the maturation of osteoclasts
Explanation:The principal mechanism by which strontium inhibits osteoclast activity is by enhancing the secretion of osteoprotegerin (OPG) and by reducing the expression of the receptor activator of nuclear factor κB ligand (RANKL) in osteoblasts.Osteoporosis is defined as low bone mineral density caused by altered bone microstructure ultimately predisposing patients to low-impact, fragility fractures.Management:Vitamin D and calcium supplementation should be offered to all women unless the clinician is confident they have adequate calcium intake and are vitamin D repleteAlendronate is the first-line treatment. Around 25% of patients cannot tolerate alendronate, usually due to upper gastrointestinal problems. These patients should be offered risedronate or etidronate.Strontium ranelate and raloxifene are recommended if patients cannot tolerate bisphosphonates.Other medications that are useful in the treatment of osteoporosis are denosumab, teriparatide, raloxifene, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 97
Correct
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What is the principle site of action of adrenocorticotrophic hormone (ACTH)?
Your Answer: Adrenal gland
Explanation:Adrenocorticotropic hormone, also known as ACTH or corticotropin, is a polypeptide tropic hormone. It is synthesized by the corticotropic cells of the anterior pituitary. It works by regulating the secretion of glucocorticoid hormones from the cortex cells in the adrenal gland. It binds to the melanocortin (MC) 2 receptors on the surface of the adrenal zona glomerulosa cells, producing cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 98
Incorrect
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Concerning the sleep-wake cycle, Melatonin is secreted by which structure in the brain following which environmental conditions?
Your Answer: Pineal gland, light
Correct Answer: Pineal gland, darkness
Explanation:Melatonin is secreted by the pineal gland located in the midline attached to the posterior roof of the third ventricle in the brain. Melatonin affects circadian rhythm in the body or the sleep wake cycle. The precursor to melatonin is serotonin and the rate limiting enzyme that converts serotonin to melatonin is low during the day time and reaches its peak during the night.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 99
Correct
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The process whereby bacterial products interact with plasma factors and cells to produce agents that attract neutrophils to an infected area is called:
Your Answer: Chemotaxis
Explanation:During an inflammatory process many cytokines are produced that act as chemokines to attract neutrophils to the site of inflammation. These include bacterial products, IL-8, C5a and LTB4.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 100
Incorrect
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The ependyma fuse with which of the following to from the choroid plexus?
Your Answer: Inferior sagittal sinus
Correct Answer: Tela choroidea
Explanation:The choroid plexus produces the cerebrospinal fluid (CSF) in the ventricles of the brain. It consists of modified ependymal cells. Tela choroidea is a region of pia mater of the meninges and underlying ependyma that’s a part of the choroid plexus. It is a very thin layer of the connective tissue of pia mater that overlies and covers the ependyma.
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This question is part of the following fields:
- Medicine
- Neurology
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SESSION STATS - PERFORMANCE PER SPECIALTY
