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Question 1
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 2
Incorrect
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A 50-year-old man with a history of hyperlipidaemia, currently under treatment with simvastatin 10mg was found to have persistently high cholesterol levels. Previous attempts to increase the dose of simvastatin have resulted in myalgia. Given this history, which one of the following lipid-regulating drugs should definitely be avoided?
Your Answer: Cholestyramine
Correct Answer: Bezafibrate
Explanation:Both fibrates and nicotinic acid have been associated with myositis, especially when combined with a statin. However, the Committee on Safety of Medicines has produced guidance which specifically warns about the concomitant prescription of fibrates with statins concerning muscle toxicity.Bezafibrate: It is a fibric acid derivative (fibrate) that has been used as a class of agents known to decrease triglyceride levels while substantially increasing HDL-C levels.Pharmacological effects:- Increases VLDL catabolism by increasing lipoprotein and hepatic triglyceride lipase.- Decreases triglyceride synthesis by inhibiting acetyl-CoA reductase.- Decreases cholesterol synthesis by inhibiting HMG-CoA reductase.Side effects:- Hypersensitivity- Primary biliary cirrhosis- Pre-existing gallbladder disease- Concurrent use with HMG-CoA inhibitors (statins) can produce myopathy- Hepatic/renal impairment in a patient warrants dose adjustment as this drug is primarily excreted via the renal mechanism.Contraindications: Concurrent use of MAO inhibitors, hypersensitivity, pre-existing cholestasis, and pregnancy.Use: It can be used to treat Barth syndrome (characterized by dilated cardiomyopathy, neutropenia (presenting with recurrent infections), skeletal myopathy and short stature)
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 3
Correct
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Phosphate absorption in the proximal tubules is via which transporting molecule?
Your Answer: Na/Pi co transporter
Explanation:Sodium/phosphate cotransporters are located in the renal proximal tubular brush border, and are the key elements in proximal tubular phosphate reabsorption and phosphate homeostasis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 4
Correct
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What catalyses the conversion of adenosine to inosine?
Your Answer: Adenosine deaminase
Explanation:Adenosine deaminase (ADA) is an enzyme involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues. ADA irreversibly deaminates adenosine, converting it to the related nucleoside inosine by the substitution of the amino group for a keto group.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 5
Incorrect
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Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer: Calcium channels
Correct Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through a process known as:
Your 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 7
Correct
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Question 8
Incorrect
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The nucleus tractus solitaries is medullary nucleus that processes the following inputs except:
Your Answer: Visceral sensation from the gut and thoracic organs
Correct Answer: Sensory input from the semi-circular canal (CN VIII)
Explanation:Located in the brain stem is a series of purely sensory nuclei known as tractus solitaries. Inputs of the nucleus tractus solitaries include:Taste information from the facial nerve (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis).Sensory information from the ear (auricular branch of the vagus nerve).Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve.Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 9
Incorrect
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VIP, GIP and somatostatin play an inhibitory role in gastric acid secretion by inactivating?
Your Answer: Enterochromatin like cells
Correct Answer: G cells
Explanation:Gastrin is secreted from the G cells. VIP, GIP and somatostatin all inhibit acid production by inhibiting the G cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 10
Incorrect
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Which one of the following have not been shown to improve mortality in patients with chronic heart failure?
Your Answer: Nitrates and hydralazine
Correct Answer: Furosemide
Explanation:A number of drugs have been shown to improve mortality in patients with chronic heart failure:
- ACE inhibitors (SAVE, SOLVD, CONSENSUS)
- spironolactone (RALES)
- beta-blockers (CIBIS)
- hydralazine with nitrates (VHEFT-1)
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 11
Incorrect
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Which vaso metabolite decreases coronary blood flow?
Your Answer: Prostaglandins
Correct Answer: Endothelin
Explanation:Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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Which of the following factors is not completely produced in the liver?
Your Answer: Factor vii
Correct Answer: Factor viii
Explanation:Factor VIII is produced in liver sinusoidal cells and endothelial cells outside of the liver throughout the body. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 13
Incorrect
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Which enzyme is deficient in the inborn error of metabolism called galactosemia?
Your Answer: Galactokinase
Correct Answer: Galactose-1-phosphate uridyl transferase
Explanation:Galactosaemia is a rare genetic autosomal recessive metabolic disorder. Lactose is broken down by the enzyme lactase into glucose and galactose. In individuals with galactosemia, the enzymes needed for further metabolism of galactose (Galactose-1-phosphate uridyltransferase) are severely diminished or missing entirely, leading to toxic levels of galactose 1-phosphate in various tissues.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 14
Incorrect
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According to the Vaughan William's classification of antiarrhythmic agents, lidocaine is a:
Your Answer: Class Ic agent
Correct Answer: Class Ib agent
Explanation:Lidocaine is an example of class IB antiarrhythmics.The Vaughan-Williams classification of antiarrhythmicsI: Membrane stabilizing agentsIA: Quinidine, Procainamide, DisopyramideIB: Lidocaine, MexiletineIC: Propafenone, Flecainide II: β blockers – Propranolol, EsmololIII: Agents widening AP – Amiodarone, Dronedarone, Dofetilide, Ibutilide, SotalolIV: Calcium channel blockers – Verapamil, DiltiazemV: Miscellaneous – Digoxin, adenosine, magnesium
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 15
Incorrect
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The triangle with the heart at its centre, using limb leads is called:
Your Answer:
Correct Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 16
Incorrect
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Which cells secrete insulin?
Your Answer:
Correct Answer: B cells of the pancreatic islets
Explanation:Insulin is synthesised and stored by the B cells of the pancreatic islets (70% of islet cells), glucagon is synthesised and stored in the A cells (20%) and somatostatin is synthesised and stored in the D cells (10%).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 17
Incorrect
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The motor speech area (Brocas Area) is:
Your Answer:
Correct Answer: Brodmann area 44
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary Sensory 3,1,2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 18
Incorrect
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In most somatic cells telomeres progressively shorten as:
Your Answer:
Correct 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 19
Incorrect
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A 31 year old female complains of bilateral proximal muscle weakness. There is marked blanching of fingers especially in response to cold weather. Lab results are as follows: Anti Jo-1: positive ANA: positiveCK: 2000 U/LESR: 60mm/hrEMG: myopathic changesPresence of which of the following signifies the worst prognosis?
Your Answer:
Correct Answer: Interstitial lung disease
Explanation:Polymyositis is an inflammatory disorder causing symmetrical, proximal muscle weakness. It is thought to be a T-cell mediated cytotoxic process directed against muscle fibres. It may be idiopathic or associated with connective tissue disorders. It may also be associated with malignancy for example small cell lung carcinoma.Dermatomyositis is a variant of the disease where skin manifestations are prominent, for example a purple (heliotrope) rash on the cheeks and eyelids.It typically affects middle-aged, female: male 3:1. Features include proximal muscle weakness +/- tenderness, Raynaud’s phenomenon, respiratory muscle weakness, interstitial lung disease: e.g. fibrosing alveolitis or organising pneumonia, dysphagia, dysphonia. Investigations: elevated creatine kinase, other muscle enzymes (lactate dehydrogenase (LD), aldolase, AST and ALT) are also elevated in 85-95% of patients, EMG, muscle biopsy. Anti-Jo-1 antibodies are seen in pattern of disease associated with lung involvement, Raynaud’s and fever. Interstitial lung disease plays a major role in morbidity and mortality in patients with polymyositis and is considered a major risk factor for premature death in patients with myositis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 20
Incorrect
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Which coronary artery supplies the right atria?
Your Answer:
Correct Answer: Right coronary
Explanation:The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 21
Incorrect
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Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer:
Correct 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 22
Incorrect
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Which segment of the nephron is impermeable to water?
Your Answer:
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 23
Incorrect
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Normally the portal venous pressure is about:
Your Answer:
Correct Answer: 5mmhg
Explanation:Under normal physiological conditions, the pressure in the portal vein, which carries blood from the gastrointestinal tract and spleen to the liver, typically ranges around 5-10 mmHg. Pressures significantly higher than this range can indicate portal hypertension, which can be associated with liver diseases such as cirrhosis.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 24
Incorrect
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Protozoa is part of which pathogenic group?
Your Answer:
Correct Answer: Eukaryotes
Explanation:Protozoa are a diverse group of unicellular eukaryotic organisms. Historically, protozoa were defined as single-celled organisms with animal-like behaviours, such as motility and predation.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 25
Incorrect
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A 32 year old woman presents with a painful elbow which she has been feeling for the past two weeks. Which of the following will be consistent with a diagnosis of tennis elbow?
Your Answer:
Correct Answer: Pain on wrist extension against resistance
Explanation:Lateral epicondylitis (tennis elbow) is an overuse injury of the hand and finger extensor tendons that originate in the lateral humeral epicondyle that occurs following repeated or excessive pronation/supination and extension of the wrist (e.g., in racquet sports). Clinical features include pain and tenderness over the lateral epicondyle and along extensor muscles and thickening of the tendons. The examiner holds the patient’s hand with the thumb placed over the lateral epicondyle – The patient makes a fist, supinates the forearm, deviates radially, and extends the fist against the examiner’s resistance which will result in pain over the lateral epicondyle. Conservative treatment includes rest, physiotherapy and orthotic braces. If this fails corticosteroids and lidocaine injections are employed. Surgery is indicated in patients with persistent symptoms despite 6 months of conservative treatment. Excision of abnormal tendon tissue; longitudinal incisions (tenotomies) in scarred and fibrotic areas to promote healing.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 26
Incorrect
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Which area in the GIT lacks Basic Electrical Rhythm?
Your Answer:
Correct Answer: Oesophagus
Explanation:The basal or basic electrical rhythm acts to coordinate peristalsis and are initiated in the interstitial cells of Cajal, specialized pacemaker cells located in the wall of the stomach, below the oesophagus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Incorrect
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In the basal ganglia, the Lentiform nucleus is formed by which two nuclei?
Your Answer:
Correct Answer: Putamen and Globus pallidus
Explanation:The Basal Ganglia are composed of the following structures: Caudate, putamen, Globus pallidus, subthalamic nucleus and substantia nigra.
The Lentiform nucleus is a biconvex structure located within the basal ganglia of the brain. It is composed of two nuclei:
- Putamen: This is the outer part of the Lentiform nucleus and is involved in regulating movements and various types of learning.
- Globus pallidus: This is the inner part of the Lentiform nucleus and is divided into two segments: the external segment (GPe) and the internal segment (GPi). It plays a key role in the regulation of voluntary movement.
These two structures together form the Lentiform nucleus, which is an integral part of the basal ganglia system involved in motor control.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 28
Incorrect
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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:
Correct 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 29
Incorrect
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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer:
Correct Answer: NADPh oxidase
Explanation:The respiratory burst is a rapid release of reactive oxygen species (ROS) from neutrophils and other phagocytes. This process is crucial for the destruction of pathogens. The key components and enzymes involved in the respiratory burst include:
- NADPH oxidase: This enzyme complex plays a central role in the respiratory burst by converting oxygen (O2) into superoxide anion (O2•-), a reactive oxygen species. This is the initial step in the production of various ROS.
- Superoxide dismutase (SOD): This enzyme converts superoxide anion (O2•-) into hydrogen peroxide (H2O2). While SOD is involved in the pathway, the respiratory burst is initiated by NADPH oxidase.
- Myeloperoxidase (MPO): This enzyme uses hydrogen peroxide (H2O2) to produce hypochlorous acid (HOCl) from chloride ions (Cl-), which is a potent antimicrobial agent. Myeloperoxidase also produces other reactive species using halide ions.
- Catalase: This enzyme degrades hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). While catalase helps to protect the cell from oxidative damage by breaking down H2O2, it is not involved in the generation of ROS during the respiratory burst.
- Adenylate cyclase: This enzyme is involved in the production of cyclic AMP (cAMP) from ATP and is not directly related to the respiratory burst.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 30
Incorrect
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What is the name of the area that indicates the site of active B lymphocyte proliferation?
Your Answer:
Correct Answer: Germinal centre
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate.
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This question is part of the following fields:
- Immunology
- Medicine
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