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Question 1
Correct
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How does the proximal convoluted tubule excrete H+?
Your Answer: Via Na+/H+ antiporter.
Explanation:H+ secretion from cells across the luminal membrane is mostly in exchange for Na+ ions, and to a small extent, through a proton ATPase. Secreted H+ react with filtered HC03- to form H2CO3.
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This question is part of the following fields:
- Medicine
- Renal
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Question 2
Correct
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Which of the following with regard to DNA mutations does not fit:
Your Answer: All gene mutations cause clinical disease entities
Explanation:All gene mutations do not cause a clinical manifestation of the disease, some gene mutations are silent mutations. They are present but do not cause any disease.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 3
Correct
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In the cardiac cycle, all of the following are true except:
Your Answer: Mitral valve is closed by contraction of papillary muscles
Explanation:Mitral valve is closed by contraction of papillary muscles: This statement is incorrect. The mitral valve closes due to the pressure difference between the left ventricle and the left atrium at the onset of ventricular systole. The papillary muscles contract to prevent prolapse of the valve into the atrium but do not cause the valve to close.
The left ventricular volume is maximal at the end of atrial systole: This statement is true. At the end of atrial systole, the atria have pushed the remaining blood into the ventricles, making the ventricular volume maximal (end-diastolic volume).
The left ventricular pressure is maximal just before the aortic valve opens: This statement is true. Left ventricular pressure peaks just before the aortic valve opens, as the ventricle contracts to overcome the pressure in the aorta.
The ejection fraction is about 55%: This statement is true. The ejection fraction, which is the percentage of blood ejected from the ventricles with each contraction, is typically around 55%.
The ‘a’ wave is due to atrial systole: This statement is true. The ‘a’ wave on the venous pressure curve corresponds to atrial systole, reflecting the increased pressure from atrial contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 4
Correct
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During which phase of the cell cycle does transcription of DNA synthesis molecules occur?
Your Answer: S
Explanation:DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further.
Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 5
Correct
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A deficiency in Niacin leads to which clinical deficiency syndrome?
Your Answer: Pellagra
Explanation:Pellagra is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhoea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time affected skin may become darker, stiff, begin to peel, or bleed.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 6
Incorrect
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What is the average life span of red blood cells?
Your Answer: 7 days
Correct 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 7
Correct
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Where in the gastrointestinal tract are Brunner glands?
Your Answer: Duodenum
Explanation:Brunner’s glands (or duodenal glands) are compound tubular submucosal glands found in that portion of the duodenum which is above the hepatopancreatic sphincter (aka sphincter of Oddi). The main function of these glands is to produce a mucus-rich alkaline secretion (containing bicarbonate) in order to:- protect the duodenum from the acidic content of chyme (which is introduced into the duodenum from the stomach);- provide an alkaline condition for the intestinal enzymes to be active, thus enabling absorption to take place; lubricate the intestinal walls.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 8
Incorrect
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Arterioles stemming from the coronary artery can also empty into the heart directly via the:
Your Answer: Thebesian veins
Correct Answer: Arteriosinusoidal vessels
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers. They include arteriosinusoidal vessels, which connect the arterioles to the heart chambers. The thebesian veins drain the capillaries into the chambers and the arterioluminal vessels drain small arteries directly into the chambers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Correct
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Which of the following statements is true of the beta- lactams:
Your Answer: Co-amoxiclav is more likely to cause obstructive jaundice than amoxicillin
Explanation:β-lactam antibiotics are a class of broad-spectrum antibiotics, consisting of all antibiotic agents that contain a β-lactam ring in their molecular structures. This includes penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems. Most β-lactam antibiotics work by inhibiting cell wall biosynthesis in the bacterial organism and are the most widely used group of antibiotics. Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring. To overcome this resistance, β-lactam antibiotics are often given with β-lactamase inhibitors such as clavulanic acid. Immunologically mediated adverse reactions to any β-lactam antibiotic may occur in up to 10% of patients receiving that agent (a small fraction of which are truly IgE-mediated allergic reactions). Rarely, cholestatic jaundice has been associated with Co-amoxiclav (amoxicillin/clavulanic acid). The reaction may occur up to several weeks after treatment has stopped, and usually takes weeks to resolve. It is more frequent in men, older people, and those who have taken long courses of treatment; the estimated overall incidence is one in 100,000 exposures.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 10
Correct
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In both innate and humoral immunity, receptors involved recognize:
Your Answer: The shape of the antigen
Explanation:Antigen receptors recognize the shape of the antigen. They identify specific epitopes and are found on T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 11
Correct
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Which one of the following features is least associated with primary hyperparathyroidism?
Your 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 12
Correct
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Platelets are stored in this body organ.
Your Answer: Spleen
Explanation:Megakaryocyte and platelet production is regulated by thrombopoietin. Each megakaryocyte produces between 1,000 and 3,000 platelets during its lifetime. An average of 1011 platelets are produced daily in a healthy adult. Reserve platelets are stored in the spleen, and are released when needed by splenic contraction induced by the sympathetic nervous system.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 13
Correct
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Regarding cardiac contractility, catecholamines exert their inotropic effect via:
Your Answer: Î’1-adrenergic receptors and gs
Explanation:Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Correct
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The following cells replicate without shortening their telomeres because they express telomerase.
Your Answer: Germ cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 15
Correct
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A 32 year old female is diagnosed with SLE based on her complaints of polyarthralgia, mouth ulcers and ANA positivity. Labs reveal normal urinalysis, urea and electrolytes. ESR is 90mm in the first hour. How will you manage this patient?
Your Answer: Hydroxychloroquine 200 mg/day
Explanation:Hydroxychloroquine is used in the management of SLE as it prevents disease progression and has relatively mild side effects, for instance headache, nausea etc. Its use reduces the usage of corticosteroids. It is particularly effective when the disease is less severe and there is no organ involvement. Cyclophosphamide and prednisolone are indicated in cases of renal, neurological and lung involvement.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 16
Correct
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What is the fat called that serves as a considerable source of heat in children?
Your Answer: Brown adipose tissue
Explanation:Brown adipose tissue, also known as BAT or brown fat, coforms the adipose tissue along with white adipose tissue (WAT) or white fat. While WAT is responsible for energy-storage, BAT is involved in thermogenesis and energy expenditure. It is more prevalent in children than in adults, and its activation during adolescence is associated to less weight gain and adiposity. BAT produces heat by non-shivering thermogenesis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 17
Correct
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Question 18
Incorrect
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What is the most common cause of primary hyperaldosteronism?
Your Answer: Adrenocortical adenoma
Correct Answer: Bilateral idiopathic adrenal hyperplasia
Explanation:Primary aldosteronism, also known as primary hyperaldosteronism or Conn’s syndrome, is excess production of the hormone aldosterone by the adrenal glands resulting in low renin levels. Primary hyperaldosteronism has a number of causes. About 66% of cases are due to enlargement of both adrenal glands and 33% of cases are due to an adrenal adenoma that produces aldosterone. Other uncommon causes include adrenal cancer and an inherited disorder called familial hyperaldosteronism
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 19
Incorrect
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A 70-year-old man presents with nocturia, hesitancy and terminal dribbling of urine. Prostate examination reveals a moderately enlarged prostate with no irregular features and a well-defined median sulcus. Blood investigations show a PSA level of 1.3 ng/mL. Among the options provided below what is the most appropriate management for this patient?
Your Answer: 5 alpha-reductase inhibitor
Correct Answer: Alpha-1 antagonist
Explanation:Benign Prostatic Enlargement or Hyperplasia (BPE/BPH) is the most probable diagnosis of the patient in question. It is a histological diagnosis characterized by proliferation of the cellular elements of the prostate. The initial treatment modality of choice is selective alpha 1 antagonists (such as Prazosin, Alfuzosin and Indoramin, and long acting agents like, Terazosin, Doxazosin, etc.) as they provide immediate relief from the bothersome lower urinary tract symptoms (LUTS).Other treatment modalities include:• Non-selective alpha blockers: no longer used due to severe adverse effects and the availability of selective alpha 1 blockers.• 5 alpha reductase inhibitors: Finasteride and Dutasteride, they target the underlying disease process and reduce the overall prostate volume. Thus, reduce the urinary retention and the lower urinary tract symptoms. (They do not provide immediate relief from LUTS and thus are not preferred as first line drugs over alpha 1 antagonists)• PDE-5 Inhibitors: The long-acting tadalafil has proven to be useful.• Surgical Treatment modalities: TURP, Prostatectomy, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 20
Correct
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Which one of the following makes up most of the adrenal cortex?
Your Answer: Zona fasciculata
Explanation:The zona fasciculata represents the widest area of the adrenal cortex, situated in the middle of the cortex. It produces glucocorticoids including; 11-deoxycorticosterone, corticosterone, and cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 21
Correct
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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: 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 22
Correct
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Which of the following makes up the thick filaments in muscle fibers?
Your Answer: Myosin
Explanation:The thick filaments are made up of myosin and the thin filaments are made up of actin. The thick filaments are twice the size of the thin filaments and are aligned to form the A band. The thin filaments extending out from the A band form the less dense I bands.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Incorrect
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Cyclic AMP is formed from ATP via which enzyme
Your Answer: Phosphodiesterase
Correct Answer: Adenylate cyclase
Explanation:Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 24
Correct
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The following products of the vascular endothelium produce vasodilation except:
Your Answer: Endothelin
Explanation:Endothelin: This is incorrect in the context of vasodilation. Endothelin is actually a potent vasoconstrictor produced by the endothelium, leading to the narrowing of blood vessels and increased blood pressure.
Nitrous oxide (Nitric oxide): This is correct for vasodilation. Nitric oxide is a powerful vasodilator produced by the endothelium, which helps relax and widen blood vessels.
Prostacyclin: This is correct for vasodilation. Prostacyclin (PGI2) is a vasodilator and inhibits platelet aggregation, helping to maintain blood flow and reduce clot formation.
Endothelial-derived hyperpolarizing factor (EDHF): This is correct for vasodilation. EDHF causes vasodilation by hyperpolarizing the smooth muscle cells of blood vessels.
Vascular endothelial growth factor (VEGF): This is correct for vasodilation. VEGF primarily promotes the growth of new blood vessels but also has vasodilatory effects through nitric oxide production.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Incorrect
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Which of the following best describes the cardiac muscle?
Your Answer: Smooth and involuntary
Correct Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Correct
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A 24 year old male, known case of hereditary angioneurotic oedema presents with recurrent fever and arthralgia which is accompanied by a rash on face and upper chest. These attacks have been refractory to treatment and have occurred recurrently requiring adrenaline on several occasions. Lab results reveal persistently reduced C4 levels. Which of the following is most likely causing his current symptoms?
Your Answer: Systemic lupus erythematosus
Explanation:Angioedema secondary to C1 inhibitor deficiency has been rarely reported to be associated with systemic lupus erythematosus. A genetic defect of C1 inhibitor produces hereditary angioedema, which is usually presented with cutaneous painless oedema, but oedema of the genital area, gastrointestinal and laryngeal tracts have also been reported. In lupus patients, angioedema may be the result of an acquired type of C1 inhibitor deficiency, most probably due to antibody formation directed against the C1 inhibitor molecule.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 27
Correct
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Question 28
Correct
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Which is NOT true of vitiligo?
Your Answer: A positive family history is not a risk factor
Explanation:The cause of Vitiligo is typically unknown. It is believed to be due to genetic susceptibility that is triggered by an environmental factor such that an autoimmune disease occurs. This results in the destruction of skin pigment cells. Risk factors include a family history of the condition or other autoimmune diseases, such as hyperthyroidism, alopecia areata, and pernicious anaemia. Vitiligo is classified into two main types: segmental and non-segmental. Most cases are non-segmental meaning they affect both sides and typically get worse with time. The prevalence of vitiligo is 0.5-1% of populations worldwide. Typical sites include backs of hands, wrists, knees, neck and around body orifices. The Koebner phenomenon refers to skin lesions appearing on lines of trauma. This occurs in vitiligo secondary to scratching.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 29
Correct
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Question 30
Correct
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Which one of these features is typical of dermatomyositis?
Your Answer: Gottron's papules over knuckles of fingers
Explanation:The main symptom of dermatomyositis include skin rash and symmetric proximal muscle weakness (in over 90% of patients) which may be accompanied by pain and tenderness. It occurs more commonly in females. Skin findings include:Gottron’s sign – an erythematous, scaly eruption occurring in symmetric fashion over the MCP and interphalangeal jointsHeliotrope or lilac rash – a violaceous eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swellingShawl (or V-) sign is a diffuse, flat, erythematous lesion over the back and shoulders or in a V over the posterior neck and back or neck and upper chest, which worsens with UV light. Erythroderma is a flat, erythematous lesion similar to the shawl sign but located in other areas, such as the malar region and the forehead. Periungual telangiectasias and erythema occur.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 31
Correct
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The onset of puberty is triggered by
Your Answer: Increase in pulsatile GNRH secretion from hypothalamus
Explanation:The onset of puberty is associated with high GNRH pulsing, which precedes the rise in sex hormones. Brain tumours which increase GNRH output may also lead to premature puberty. The cause of the GNRH rise is unknown.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 32
Correct
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Which of the following can trigger parietal cell secretion?
Your Answer: Gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 33
Correct
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Which of the following is a product of D cells
Your Answer: Somatostatin
Explanation:Somatostatin is secreted by D cells, HCL and intrinsic factor secreted by parietal cells. Trefoil peptides are secreted by mucus secreting goblet cells and gastrin releasing peptide (grp) by post-ganglionic fibers of the vagus nerve (which innervate the G cells of the stomach).
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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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The process by which RNA fragments are separated by gel electrophoresis and transferred onto a membrane sheet is called:
Your Answer: Northern blotting
Explanation:Blots of the gel can be made from using nitrocellulose paper. Northern blots are produced when a fragment of radioactive DNA hybridize with RNA on a nitrocellulose blot of a gel and southern blots are produced when DNA hybrize with DNA on a nitrocellulose blot of the gel.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 35
Correct
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The immunoglobulin found in the highest concentration in humans is
Your Answer: IgG
Explanation:Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 36
Correct
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What is the main function of vitamin E?
Your Answer: It is an antioxidant
Explanation:Vitamin E has many biological functions, the antioxidant function being the best known. Other functions include enzymatic activities, gene expression, and neurological function(s).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 37
Correct
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A 20-year-old female has been admitted with an acute infection. She gives a history suggestive of hypersensitivity to amoxicillin. After consultation with the allergy specialist, she has now been diagnosed with an IgE mediated penicillin allergy. Which of the following drugs should be avoided in this patient?
Your Answer: Cefalexin
Explanation:Cefalexin should be avoided in this patient.This patient is known to have a severe penicillin allergy. None of the above antibiotics are penicillin based. However, 0.5 – 6.5% of patients who are proven to have an IgE mediated penicillin allergy will also be allergic to cephalosporins, including cefalexin. Penicillin, cephalosporins, and carbapenems are all members of the beta-lactam group of antibiotics and share a common beta-lactam ring. There is, therefore, a small risk of allergy cross-over between all these antibiotics. The rates of allergy cross-over are lower with second and third-generation cephalosporins than first-generation cephalosporins such as cefalexin.It is important to question the patient carefully to ascertain what symptoms they had on exposure to penicillin. Symptoms such as an urticarial rash or itching make it more likely that they have an IgE mediated allergy.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 38
Incorrect
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Which of the following statements is true regarding chromosomes?
Your Answer: The centromere divides the chromosome into the long (q) and short (p) arms
Correct Answer: All are true
Explanation:All of the above mentioned statements are true regarding chromosomes.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 39
Correct
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A 28-year-old female admitted for a course of chemotherapy, has been taking high dose steroids for a few days. The nurses report that she is very agitated and talks about trying to open the window of her room and jump out from the fourth floor.You review her notes and see that she admits to drinking a few glasses of wine per week and has smoked cannabis on a few occasions.On examination her BP is 145/88 mmHg, her pulse is 80 bpm.Blood investigations reveal:Haemoglobin: 12.1 g/dL (11.5-16.5)WBC count: 16.2 x 103/dL (4-11)Platelets: 200 x 109/L (150-400)C-reactive protein: 9 nmol/l (<10)Sodium: 140 mmol/l (135-146)Potassium: 3.9 mmol/l (3.5-5)Creatinine: 92 μmol/l (79-118)Which of the following is the most likely diagnosis?
Your Answer: Corticosteroid-related psychosis
Explanation:Agitation, hypomania and suicidal intent within a few days after initiating corticosteroid therapy is highly suggestive of a diagnosis of corticosteroid-induced psychosis.In some patients corticosteroid related psychosis has been diagnosed up to 12 weeks or more after commencing therapy.Euphoria and hypomania are considered to be the most common psychiatric symptoms reported during short courses of steroids.During long-term treatment, depressive symptoms were the most common. Higher steroid doses appear to carry an increased risk for such adverse effects; however, there is no significant relationship between dose and time to onset, duration, and severity of symptoms. Management: Reduction or cessation of corticosteroids is the mainstay of treatment for steroid psychosis. For those patients who cannot tolerate this reduction/cessation of steroids, mood stabilizers may be of some benefit.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 40
Incorrect
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A 64 year old female presents with sudden onset pain, swelling and stiffness in her right knee. Her medical history is significant for osteoarthritis affecting her hand joints and diet controlled diabetes mellitus. On examination, the right knee is swollen, erythematous and tender. Which of the following tests would be most useful in the diagnosis of this case?
Your Answer: X-ray of the knee
Correct Answer: Aspiration and examination of the synovial fluid
Explanation:Arthrocentesis should usually be done when there is a suspicion of pseudogout or septic arthritis as in this case which leads to an early diagnosis and prompt treatment. Polarized microscopy demonstrates weakly positively birefringent rhomboid crystals which are blue when parallel to light and yellow when perpendicular to light. Elevated serum uric acid levels that cause gout are usually found after large consumption of alcohol or meat, or post surgery. Autoimmune diseases like SLE, RA etc require an autoimmune screen.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 41
Incorrect
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A 70-year-old male presents with chest pain. His past medical history includes hypertension and angina. He continues to smoke about 20 cigarettes per day despite being advised about lifestyle modifications.Blood investigations obtained in the emergency department show:Na+: 133 mmol/lK+: 3.3 mmol/lUrea: 4.5 mmol/lCreatinine: 90 μmol/lWhich among the following is the most likely explanation for the abnormalities seen in the above investigations?
Your Answer: Spironolactone therapy
Correct Answer: Bendroflumethiazide therapy
Explanation:The blood investigations in this patient reveal hyponatremia as well as hypokalaemia. Among the options provided, Bendroflumethiazide therapy can cause the above presentation with the electrolyte disturbances. Note:- Spironolactone is a potassium-sparing diuretic that is associated with hyperkalaemia.- Enalapril therapy can cause side effects of dizziness, hypotension, cough, and rarely a rash.- Felodipine therapy can cause side effects of dizziness, headache, cough, and palpitations.
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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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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 43
Correct
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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 44
Correct
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Amongst the following cells, which is responsible for the secretion of defensins?
Your Answer: Neutrophils
Explanation:Eosinophils are phagocytic and they are directed against helminths. Basophils are involved in allergic reactions and contain histamine and vasoactive granules in their cytoplasm. Mast cells are similar to basophils. Monocytes differentiate into macrophages in the tissue, secret interleukins and are phagocytic. Neutrophils are phagocytic but are also responsible for secreting defensins.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 45
Incorrect
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A 28 year old female presents to the rheumatology clinic for review. She has a history of adult onset Still's disease and complains of joint pains and persistent skin rash despite undergoing treatment with methotrexate and etanercept. On examination, an erythematous macular rash and active synovitis is noted. CRP is high (95 mg/dl). Which of the following interventions would be most appropriate?
Your Answer: Rituximab
Correct Answer: Anakinra
Explanation:Adult onset Still’s disease (AOSD) is an uncommon systemic inflammatory disease on the clinical spectrum of autoinflammatory disorders. Its presentation and clinical course may result in several well-differentiated phenotypes: from a systemic and highly symptomatic pattern to a chronic articular pattern. Overproduction of numerous pro-inflammatory cytokines is observed in AOSD. Anakinra, a human interleukin (IL)-1R antagonist, has recently been approved in the treatment of AOSD. Denosumab is a RANK ligand inhibitor used in the treatment of osteoporosis. Mepolizumab is used in the treatment of severe asthma with elevated eosinophils. There is some evidence to support the use of tocilizumab, an anti-IL6 monoclonal antibody in adult onset Still’s, but there is stronger data favouring the use of tocilizumab in the treatment of rheumatoid arthritis. Rituximab is usually reserved for patients who are unresponsive to anakinra.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 46
Incorrect
-
Where is leptin synthesized and secreted?
Your Answer: Yellow adipose tissue
Correct 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 47
Correct
-
Amino acid reabsorption occurs most markedly in the?
Your Answer: Proximal convoluted tubule
Explanation:Renal protein reabsorption is the part of renal physiology that deals with the retrieval of filtered proteins, preventing them from disappearing from the body through the urine. Almost all reabsorption takes place in the proximal tubule. Only ,1% is left in the final urine.
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This question is part of the following fields:
- Medicine
- Renal
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Question 48
Incorrect
-
The formation of superoxide is catalysed by which enzyme?
Your Answer: Superoxide dismutase
Correct Answer: NADPH oxidase
Explanation:Superoxide is biologically toxic and is deployed by the immune system to kill invading microorganisms. In phagocytes, superoxide is produced in large quantities by the enzyme NADPH oxidase for use in oxygen-dependent killing mechanisms of invading pathogens.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 49
Correct
-
Endothelial cells are attached to adjacent cells by adherent junctions via:
Your Answer: Cadherins
Explanation:Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 50
Correct
-
An elderly man presents with fever of 38°C and a very severe headache. His BP is 85/50 mm Hg. He has neck stiffness and photophobia. What is the most appropriate management?
Your Answer: CT head
Explanation:In elderly patients, symptoms suggestive of meningitis could be due to an intracranial mass lesion (such as abscess, tumour or an intracerebral haematoma). Therefore elderly patients are increased risk of cerebral herniation from an LP. A CT head should be done before an LP to exclude a mass lesion.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 51
Correct
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Question 52
Incorrect
-
Nucleic acids are split into nucleotides in the:
Your Answer: Stomach
Correct Answer: Intestine
Explanation:The pancreas is the major source for all the digestive enzymes including nucleases which split nucleic acids into nucleotides primarily in the small intestine.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 53
Correct
-
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: 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 54
Correct
-
A 47-year-old woman diagnosed with oestrogen receptor positive breast cancer three months ago was started on treatment with tamoxifen. Which of the following is most likely a complaint of this patient during her review today?
Your Answer: Hot flushes
Explanation:The most likely complaint of this patient would be hot flushes.
Alopecia and cataracts are listed as possible side-effects, however they are not as prevalent as hot flushes, which are very common in pre-menopausal women.
Tamoxifen is a Selective Oestrogen Receptor Modulator (SERM) which acts as an oestrogen receptor antagonist and partial agonist. It is used in the management of oestrogen receptor-positive breast cancer
Adverse effects:
- Menstrual disturbance: vaginal bleeding, amenorrhoea
- Hot flushes – 3% of patients stop taking tamoxifen due to climacteric side-effects.
- Venous thromboembolism.
- Endometrial cancer (although antagonistic with respects to breast tissue, tamoxifen may serve as an agonist at other sites. Therefore the risk of endometrial cancer is increased). Raloxifene is a pure oestrogen receptor antagonist and carries a lower risk of endometrial cancer.
Tamoxifen is typically used for 5 years following the removal of the tumour.
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 55
Incorrect
-
Which lipoprotein contains the most cholesterol esters?
Your Answer: Chylomicrons
Correct Answer: LDL
Explanation:LDL and HDL transport both dietary and endogenous cholesterol in the plasma, but LDL is the main transporter of cholesterol and cholesteryl esters.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 56
Correct
-
Which of the following is correctly paired?
Your Answer: F cells : pancreatic polypeptide
Explanation:Pancreatic polypeptide is secreted by F-cells, which represent the smallest proportion of islet cells in the pancreas. These cells establish the embryological origin of the pancreas. Pancreatic polypeptide regulates endocrine and exocrine activities by the pancreas.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 57
Correct
-
What is the function of cytotoxic T cells?
Your Answer: Kill by inserting perforins and by initiating apoptosis
Explanation:Cytotoxic T cells, once activated, approach the infected cell, insert perforins and release granzymes inducing apoptosis.
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This question is part of the following fields:
- Immunology
- Medicine
-
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Question 58
Correct
-
The breakdown of superoxide is catalysed by which enzyme?
Your Answer: Superoxide dismutase
Explanation:As superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide-scavenging enzyme superoxide dismutase, or SOD. SOD is an extremely efficient enzyme; it catalyses the neutralization of superoxide nearly as quickly as the two can diffuse together spontaneously in solution.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 59
Correct
-
Where is the site of action of spironolactone?
Your Answer: Distal convoluted tubule
Explanation:Spironolactone is an aldosterone antagonist which acts in the distal convoluted tubule. It is a potassium-sparing diuretic that prevents the body from absorbing too much salt and keeps the potassium levels from getting too low. Spironolactone is used to treat heart failure, high blood pressure (hypertension), or hypokalaemia (low potassium levels in the blood).
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This question is part of the following fields:
- Medicine
- Pharmacology
-
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Question 60
Correct
-
In meiosis, the period of prophase 1 involves:
Your Answer: Replicated DNA condensing to form visible chromosomes
Explanation:Prophase 1 has been divided into five different stages (laptotene, zygotene, pachytene, diplotene and diakinesis). In prophase 1, chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 61
Incorrect
-
Which one of the following is true about bone marrow?
Your Answer: With blood loss red marrow is converted to yellow marrow
Correct Answer: At birth the bone marrow is entirely red marrow and is converted to yellow marrow with age
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells. Red blood cells, platelets, and most white blood cells arise in red marrow. Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 62
Incorrect
-
In the functional unit of the liver (acinus), the oxygenation…
Your Answer: Increases towards the centre
Correct Answer: Reduces towards the centre
Explanation:Cells located close to the portal triad or peripheral zone which consist of arterioles from the hepatic artery are the most oxygenated cells. Cells in the central zone are least oxygenated and mainly receive blood supply from the central vein which is a branch of the hepatic vein.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 63
Incorrect
-
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: 10 mg
Correct 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 64
Incorrect
-
Regarding blood supply to the heart;
Your Answer: Coronary arteries fill as the heart contracts
Correct Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 65
Incorrect
-
The central veins in the liver:
Your Answer: Drain directly into the inferior vena cava (IVC)
Correct Answer: Coalesce to form the hepatic vein
Explanation:The central veins coalesce to form the hepatic vein which in turn drains into the inferior vena cava. The portal vein mainly carries blood from different parts of the GIT and is not drained to the inferior vena cava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 66
Correct
-
A 62 year old female has complained she feels unsteady when she is walking. She is examined and is found to have pyramidal weakness of her left lower leg. She also has reduced pain and temperature sensation on her right leg and right side of her torso up to the umbilicus. Her joint position sense is also impaired in her left big toe but is found to be normal elsewhere. She has definite left extensor plantar response, and the right plantar response is equivocal. Where is the lesion?
Your Answer: Left mid-thoracic cord
Explanation:In Brown-Sequard syndrome, there is paralysis and loss of proprioception, which occurs on the same (ipsilateral) side of the body, as the lesion. Loss of pain and temperature sensation, therefore, occurs on the opposite (contralateral) side of the body as the lesion.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
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Question 67
Correct
-
What is the function of the macula densa, located in the wall of the thick ascending limb?
Your Answer: Tubuloglomerular feedback.
Explanation:Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal. Tubuloglomerular feedback is one of several mechanisms the kidney uses to regulate glomerular filtration rate (GFR). It involves the concept of purinergic signalling, in which an increased distal tubular sodium chloride concentration causes a basolateral release of adenosine from the macula densa cells. This initiates a cascade of events that ultimately brings GFR to an appropriate level.
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This question is part of the following fields:
- Medicine
- Renal
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Question 68
Incorrect
-
With regard to the cell membrane:
Your Answer: In eukaryotes, have a simple structure
Correct Answer: It consists of an outer hydrophilic & an inner hydrophobic layer
Explanation:The cell membrane consists primarily of a thin layer of amphipathic phospholipids that spontaneously arrange with the hydrophobic tail regions on the inside and the hydrophilic head regions outside. Membranes typically have a large content of proteins, around 50% of membrane volume.
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This question is part of the following fields:
- Cell Biology
- Medicine
-
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Question 69
Incorrect
-
Regarding short-chain fatty acids, all the following are true except:
Your Answer: They promote Na+ absorption
Correct Answer: They are produced in the small intestine but their absorption occurs in the colon
Explanation:Short chain fatty acids (SCFAs) have carbon chains of 2-5 carbon atoms. They are produced in the large intestine and are also absorbed there. They exert a trophic effect on the colonic epithelial layer in absorption of sodium. In the absence of short chain fatty acids there is a loss of sodium and water. Transport of SCFA is coupled with sodium thus absorption leads to the accumulation in the lumen of HCO3, a rise in pH, fall in pCO2 and stimulation of Na+ and water transport. The effect on Na+ transport is thought to indicate the presence of a Na+/H+ exchange in the cell membrane.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 70
Incorrect
-
The role of the hemidesmosome is?
Your Answer: Cell signalling
Correct Answer: Attaches cells to underlying basal lamina
Explanation:Hemidesmosomes connect the basal surface of epithelial cells via intermediate filaments to the underlying basal lamina. The transmembrane proteins of hemidesmosomes are not cadherins, but another type of protein called integrin.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 71
Incorrect
-
Where is Vitamin B12 mainly stored in the body?
Your Answer: Muscle
Correct Answer: Liver
Explanation:The total amount of vitamin B12 stored in body is about 2–5 mg in adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is lost per day by secretions into the gut, as not all these secretions are reabsorbed.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 72
Correct
-
Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer: Troponin c
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 73
Incorrect
-
What is the most important source of heat production in the body?
Your Answer: Smooth muscle contraction
Correct Answer: Skeletal muscle contraction
Explanation:Thermogenesis is the process by which organisms produce heat. Through skeletal muscle contraction, or shivering, ATP is converted into kinetic energy, some of which converts into heat. These muscle contractions produce about 70% of total body heat.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 74
Incorrect
-
A 32 year old male who has recently returned from a trip to Thailand presents with congestion of eyes and swelling of the knee joint. He completed a course of antibiotics for dysentery 4 weeks back. He experiences no dysuria and urine examination is normal. Which further information would be most useful in establishing a diagnosis?
Your Answer: Blood culture
Correct Answer: History and physical examination
Explanation:The patient most likely has reactive arthritis which is usually diagnosed on history and clinical examination. The classic triad of symptoms include conjunctivitis, urethritis and arthritis. Arthritis and conjunctivitis may occur 4-6 weeks after a gastrointestinal or genitourinary infection. Arthritis usually occurs acutely, mostly involving the lower limb and is asymmetrical. Blood culture, urine culture and arthrocentesis (joint aspiration) will not yield positive results.
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This question is part of the following fields:
- Connective Tissue
- Medicine
-
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Question 75
Incorrect
-
Which ion channel does not contribute to the myocardial action potential?
Your Answer: Transient outward potassium channel
Correct Answer: Chloride channel
Explanation:The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 76
Incorrect
-
Absolute refractory period in a cardiac action potential graph occurs during.
Your Answer: Initial rapid repolarization
Correct Answer: All of the above
Explanation:Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 77
Incorrect
-
Which protein in the HIV genome is responsible for binding to the host CD4 cells?
Your Answer: p17
Correct Answer: gp120
Explanation:HIV can infect a variety of immune cells such as CD4+ T cells, macrophages, and microglial cells. HIV-1 entry to macrophages and CD4+ T cells is mediated through interaction of the virion envelope glycoproteins (gp120) with the CD4 molecule on the target cells and also with chemokine coreceptors.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
-
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Question 78
Incorrect
-
The hippocampus is involved in the memory of:
Your Answer: Classical conditioning
Correct Answer: Facts
Explanation:The hippocampus plays an important role in forming new memories about experienced events. Some researchers say that hippocampus plays a major role in declarative memory for example memory of facts.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 79
Correct
-
What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?
Your Answer: Shifts the diastolic pressure curve upward and leftward
Explanation:Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 80
Incorrect
-
Question 81
Incorrect
-
What is the function of Activated protein C?
Your Answer: Inactivates t-pa
Correct Answer: Inactivates factor Va
Explanation:Activated Protein C (APC) is a crucial protein in the regulation of blood coagulation. Its primary functions include:
- Inactivating Factor Va: APC inactivates Factor Va, which is a cofactor for the conversion of prothrombin to thrombin by Factor Xa. By inactivating Factor Va, APC reduces thrombin formation, thereby acting as an anticoagulant.
- Inactivating Factor VIIIa: APC also inactivates Factor VIIIa, another cofactor that assists Factor IXa in the conversion of Factor X to Factor Xa. This further contributes to its anticoagulant effect.
These actions help to regulate blood clotting and prevent excessive thrombosis.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 82
Correct
-
An 82 year old male woke up experiencing incoherent speech - he is also finding it difficult to find the right words to explain his thoughts. Doctors have examined him, and everything else appears to be normal. They have also found that his comprehension is good. From the list of options, choose the anatomical site which in this instance, is most likely affected.
Your Answer: Broca’s Area
Explanation:The combination of good comprehension but poor speech quality in this patient is consistent with damage to the Broca’s area. The Wernicke’s area is responsible for the understanding of speech, and so is not consistent with this patient.
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This question is part of the following fields:
- Geriatrics
- Medicine
-
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Question 83
Incorrect
-
Why does arterial blood pressure drop during pregnancy?
Your Answer: Decreased sympathetic tone
Correct Answer: Progesterone relaxes vascular smooth muscle
Explanation:Progesterone relaxes vascular smooth muscle thus resulting In a decrease in total peripheral resistance. This accounts for the increase in the cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 84
Incorrect
-
The Sinoatrial node in the majority of people is supplied by the?
Your Answer: Anterior interventricular artery
Correct Answer: Right coronary artery
Explanation:In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 85
Incorrect
-
Periodic fevers occur in humans with mutations in the gene for pyrin. Pyrin is a protein found in which one of the following cells?
Your Answer: Eosinophils
Correct Answer: Neutrophils
Explanation:Pyrin, also known as marenostrin or TRIM20, is a protein encoded by the Mediterranean fever (MEFV) gene, causing the autoinflammatory disease familial Mediterranean fever (FMF). Pyrin produces an increased sensitivity to intracellular signals. It is produced mainly in neutrophils, which display an increased ratio of cells entering apoptosis when exposed to pyrin.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
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Question 86
Incorrect
-
Where is the major site of purine synthesis?
Your Answer: Bone marrow
Correct Answer: Liver
Explanation:The major site of purine synthesis is in the liver. Purines are biologically synthesized as nucleotides and in particular as ribotides.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 87
Incorrect
-
Which one of the following is able to move across cell membranes by passive diffusion?
Your Answer: Ca2+
Correct Answer: CO2
Explanation:The cell membrane is permeable to water molecules and a few other small, uncharged, molecules like oxygen (O2) and carbon dioxide (CO2). Larger molecules like glucose or charged ions are unable to cross passively.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 88
Correct
-
In most somatic cells telomeres progressively shorten as:
Your Answer: The cell divides
Explanation:Telomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 89
Incorrect
-
90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Spleen
Correct Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 90
Incorrect
-
In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through a process known as:
Your Answer: Translocation
Correct Answer: Gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
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This question is part of the following fields:
- Genetics
- Medicine
-
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Question 91
Incorrect
-
What is the average life span of neutrophils?
Your Answer: 7 weeks
Correct Answer: 24 hours
Explanation:The average lifespan of inactivated human neutrophils in the circulation has been reported by different approaches to be between 5 and 90 hours.
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This question is part of the following fields:
- Haematology
- Medicine
-
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Question 92
Incorrect
-
The apical enzyme responsible for the oxidation and reaction of iodide with thyroglobulin is:
Your Answer: Pendrin
Correct Answer: Thyroid peroxidise
Explanation:Thyroid peroxidase is an enzyme that is secreted into the thyroid colloid. It works by oxidizing iodide ions into iodine which are incorporated into thyroglobulin, in order to produce T3 and T4.
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This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 93
Correct
-
Which one of the following statements regarding the normal distribution is correct?
Your Answer: Mean = mode = median
Explanation:Normal distribution, also known as the Gaussian distribution, is a probability distribution that is symmetric about the mean. The normal distribution has the following properties:- It is symmetric around the mode, the median and the mean of the distribution.- It is unimodal- The area under the curve and over the x-axis is unity (i.e. equal to one).- Its density has two inflection points.- Its density is log-concave.The standard deviation (SD) is a measure of how much dispersion exists from the mean. SD = square root (variance)
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 94
Incorrect
-
Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer: Beta receptors
Correct Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 95
Incorrect
-
The predominant receptors in the hearts conduction system are?
Your Answer: Α1
Correct Answer: Î’1
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
-
-
Question 96
Incorrect
-
Which of the following is the most common causative organism in infective endocarditis?
Your Answer: Gram-negative bacilli
Correct Answer: Streptococcus viridans
Explanation:Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 97
Correct
-
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 98
Correct
-
A 30-year-old woman is admitted for drainage of an abscess in her left forearm. She has revealed that she was regular heroin user and has stopped for the past few days. Clinical signs are pointing towards opioid withdrawal. What is the next step in managing this patient?
Your Answer: Give her 10 mg of methadone syrup and wait 60 min to determine its effect
Explanation:The next step in managing this patient is to give 10 mg and continue administering in 10 mg increments each hour until symptoms are under control.Methadone alleviates opioid withdrawal symptoms and reduces cravings. Methadone is useful for detoxification from longer-acting opioids such as morphine or methadone itself.Methadone should be used with caution if the patient has:Respiratory deficiencyAcute alcohol dependenceHead injuryTreatment with monoamine oxidase inhibitors (MAOIs)Ulcerating colitis or Crohn’s diseaseSevere hepatic impairmentThe dose must be reviewed on a daily basis and adjusted based upon how well the symptoms are controlled and the presence of side effects. The greater the dose of opioids used by the patient, the greater the dose of methadone required to control withdrawal symptoms. To avoid the risk of overdose in the first days of treatment The recommended dosing of methadone is 30mg in two doses of 15mg morning and evening.It is important to note that a methadone dose equivalent to what the patient reports they are taking should never be given. It is rare to need more than 40 mg per 24 hours: beware of overdosing which can lead to respiratory arrest.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 99
Correct
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When during the cell cycle does DNA replication occur?
Your Answer: S phase
Explanation:The S phase is known as the synthesis phase. During this phase DNA will begin to replicated, as well as the synthesis of the centrosomes and associated proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 100
Incorrect
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The endothelium of the sinusoids has the following important function:
Your Answer:
Correct Answer: Highly fenestrated, large subendothelial spaces, many macrophages
Explanation:Substances absorbed in the intestines reach the liver via the portal vein and contain toxic substances that needs to be detoxified in hepatocytes. Thus, hepatic sinusoids are fenestrated and contain large spaces which allows passage of substances freely. These fenestrations are rich in Kupffer cells which are macrophages.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
