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Question 1
Correct
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Anti-gastroesophageal reflux mechanisms include the following except:
Your Answer: Peristaltic movements of the oesophagus
Explanation:The lower oesophageal sphincter contracts preventing reflux of acid into the oesophagus. The sling muscles of the stomach, the crura of the diaphragm and the phreno-oesophageal ligament all play an important role in constricting the lower portion of the oesophagus and preventing reflux. Peristaltic movements do not stop the acid reflux.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 2
Correct
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Which of the following statements regarding psoriasis is incorrect?
Your Answer: Mediated by type 2 helper T cells
Explanation:Psoriasis is a long-lasting autoimmune disease characterized by patches of skin typically red, dry, itchy, and scaly. Psoriasis can affect the nails and produces a variety of changes in the appearance of finger and toe nails including pitting and onycholysis. Nail psoriasis occurs in 40–45% of people with psoriasis affecting the skin and has a lifetime incidence of 80–90% in those with psoriatic arthritis. Psoriasis is mediated by type 1 helper T cells which are involved in the cell mediated response.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 3
Correct
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From which of the following can niacin be synthesized in humans
Your Answer: Tryptophan
Explanation:Niacin, is also known as vitamin B3. The liver can synthesize niacin from the essential amino acid tryptophan, requiring 60 mg of tryptophan to make one mg of niacin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 4
Correct
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Where would one find pericytes around endothelial cells?
Your Answer: Post-capillary venules
Explanation:Pericytes release a wide variety of vasoactive agents which regulate the flow through the junction between endothelial cells.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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A 24-year-old student is brought to A&E having ingested at least 20 tablets of paracetamol 8 hours earlier. She weighs 61kg. What should her immediate management consist of?
Your Answer: Intravenous N-acetylcysteine
Explanation:Activated charcoal is useful if given within one hour of the paracetamol overdose. Liver function tests, INR and prothrombin time will be normal, as liver damage may not manifest until 24 hours or more after ingestion. The antidote of choice is intravenous N-acetylcysteine, which provides complete protection against toxicity if given within 10 hours of the overdose.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 6
Correct
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What are the diagnostic criteria for an ST segment elevation type of acute myocardial infarction?
Your Answer: 1 mm ST elevation in 2 limb leads
Explanation:The current guidelines for the ECG diagnosis of the ST segment elevation type of acute myocardial infarction require at least 1 mm (0.1 mV) of ST segment elevation in the limb leads, and at least 2 mm elevation in the precordial leads. These elevations must be present in anatomically contiguous leads. (I, aVL, V5, V6 correspond to the lateral wall; V3-V4 correspond to the anterior wall ; V1-V2 correspond to the septal wall; II, III, aVF correspond to the inferior wall.)
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Incorrect
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Which segment of the nephron is impermeable to water?
Your Answer: Descending limb of Henle
Correct Answer: Ascending limb of Henle
Explanation:Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the counter current exchange mechanism employed by the loop.
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This question is part of the following fields:
- Medicine
- Renal
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Question 8
Incorrect
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The predominant receptors in the hearts conduction system are?
Your Answer: Muscarinic
Correct 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 9
Correct
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Myocardial oxygen consumption is increased by:
Your Answer: An increase in after load
Explanation:Cardiac oxygen consumption is directly related to the amount of tension that develops in the ventricles. It is increased by an increased size of heart, increased afterload, increased contractility and increased heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Correct
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Which mechanism of action do Quinolones use?
Your Answer: Inhibit DNA gyrase
Explanation:The quinolones are a family of synthetic broad-spectrum antibiotic drugs. Quinolones exert their antibacterial effect by preventing bacterial DNA from unwinding and duplicating.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 11
Correct
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Question 12
Incorrect
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Catecholamines…
Your Answer: Are both positive ionotropic and negative chronotropic
Correct Answer: Activate adenylyl cyclase
Explanation:Norepinephrine and epinephrine activate or deactivate adenylyl cyclase resulting in a decrease or an increase in the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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Where does one find the thyroid receptors?
Your Answer: Cell membrane
Correct Answer: Cell nucleus
Explanation:Unlike many of the steroid receptors, inactive receptors for T3 are located in the nucleus. T4 is first converted into T3 within the cytoplasm of the cell, T3 then enters the nucleus and binds to its receptor. The hormone-receptor complex can now bind to DNA and activate specific genes.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 14
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 15
Incorrect
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High titre of which of the following antibodies is not considered diagnostic for the mentioned disease?
Your Answer: Anti-centromere antibodies in limited systemic sclerosis
Correct Answer: Rheumatoid factor in rheumatoid arthritis (RA)
Explanation:Diagnosis of RA is mainly based on clinical features (e.g., morning stiffness, symmetrical joint swelling) and laboratory tests (e.g., anti-CCP). Rheumatoid factor is not very specific for this disease and hence has low reliability. X-ray findings (e.g., soft tissue swelling or joint space narrowing) occur late in the disease and are therefore not typically used for diagnosis.
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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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Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are true except:
Your Answer: In knockout mouse models a gene is turned on through targeted mutation
Explanation:In RFLP, polymorphism occurs in 98% of the non coding genome, resulting in no phenotypical change in the organism. A gene is not turned on by a mutation, rather the mutation at the restriction site will alter the DNA and the DNA will now form fragments of different lengths. PCR is a better technique than RFLP.
A knockout, as related to genomics, refers to the use of genetic engineering to inactivate or remove one or more specific genes from an organism. Scientists create knockout organisms to study the impact of removing a gene from an organism, which often allows them to then learn something about that gene’s function.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 17
Correct
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Which of the following is an example of a ketone body?
Your Answer: Acetoacetate
Explanation:Ketone bodies are three water-soluble molecules (acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone) that are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise, alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 18
Correct
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Where is the most erythropoietin produced?
Your Answer: Kidneys
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
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Question 19
Incorrect
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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: Alopecia
Correct 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 20
Correct
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In addition to its role in digestion and absorption of fats, bile:
Your Answer: Is the major excretory route for lipid-soluble waste products
Explanation:The end product of haem metabolism is bilirubin and jaundice is caused by increased bilirubin levels in the blood. Gallstones are mainly caused by cholesterol and bile pigments. Bile is the main route of excretion for lipid soluble waste products whereas urine is the main route of excretion of water soluble waste products.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Incorrect
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Which structure forms the major part of the sternocostal surface of the heart?
Your Answer: Left ventricle
Correct Answer: Right ventricle
Explanation:The anterior (sternocostal) surface is formed mainly by the right ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Correct
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Which of the atrial pressure changes represents the a-wave of the JVP
Your Answer: 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 23
Incorrect
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Which of the following best describes the cardiac muscle?
Your Answer: Smooth and voluntary
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 24
Incorrect
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In cardiac muscle, which of the following is directly responsible for the release of Ca2+ stored in the sarcoplasmic reticulum (calcium-induced calcium release)?
Your Answer: Transmission of the action potential via the T system
Correct Answer: Ryanodine receptor (RyR)
Explanation:Ryanodine receptor (RyR) is a ligand-gated Ca2+ channel with Ca2+ as its natural ligand. In skeletal muscle, Ca2+ entry from ECF by this route is not required for Ca2+ release. Instead, the DHPR that serves as the voltage sensor unlocks release of Ca2+ from the nearby SR via physical interaction with the RyR. The release is amplified through ca-induced ca release. However, in cardiac muscle, it is the influx of extracellular Ca2+ through the voltage-sensitive DHPR in the T system that triggers ca-induced ca release trough the RyR at the SR.
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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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Regarding carbohydrates absorption;
Your Answer: Intestinal glucose absorption requires phosphorylation
Correct 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 26
Correct
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The ENaC Transporter occurs in which part of the renal tubule?
Your Answer: Collecting duct
Explanation:The epithelial sodium channel (ENaC) is a membrane-bound ion channel that is selectively permeable to Na+ ions. It is involved primarily in the reabsorption of sodium ions at the collecting ducts of the kidney’s nephrons.
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This question is part of the following fields:
- Medicine
- Renal
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Question 27
Correct
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Question 28
Incorrect
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Which of the following cells secrete glucagon?
Your Answer: G cells
Correct Answer: A cells
Explanation:Glucagon counteracts hypoglycaemia and opposes insulin by promoting gluconeogenesis and glycogenolysis. It also decreases fatty acid synthesis in the liver and adipose tissue, and promotes lipolysis. It is secreted by the pancreatic islet α-cells. Its production is regulated by the insulin produced in β-cells.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 29
Incorrect
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What is the function of the pro-apoptotic Bcl-2 family of proteins, Bax and Bak?
Your Answer: Bring the death domains together
Correct Answer: Form permissive pores in the mitochondrial membrane
Explanation:The pro-apoptotic proteins in the BCL-2 family, including Bax and Bak, normally act on the mitochondrial membrane to promote permeabilization and release of cytochrome C and ROS, that are important signals in the apoptosis cascade. Growing evidence suggests that activated BAX and/or Bak form an oligomeric pore, MAC in the mitochondrial outer membrane. This results in the release of cytochrome c and other pro-apoptotic factors from the mitochondria, often referred to as mitochondrial outer membrane permeabilization, leading to activation of caspases.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 30
Incorrect
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Which of the following runs in the upper part of the falx cerebri?
Your Answer: Diaphragm sella
Correct Answer: Superior sagittal sinus
Explanation:Falx cerebri is a sickle cell fold of dura between the two hemispheres. Its posterior part blends with the superior part of the tentorium cerebelli. The superior sagittal sinus runs in its upper fixed margin, the inferior sagittal sinus in the free concave margin and the straight sinus along its attachment to the tentorium cerebelli.
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This question is part of the following fields:
- Medicine
- Neurology
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SESSION STATS - PERFORMANCE PER SPECIALTY
