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Question 1
Correct
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What is the principle site of action of adrenocorticotrophic hormone (ACTH)?
Your Answer: Adrenal gland
Explanation:Adrenocorticotropic hormone, also known as ACTH or corticotropin, is a polypeptide tropic hormone. It is synthesized by the corticotropic cells of the anterior pituitary. It works by regulating the secretion of glucocorticoid hormones from the cortex cells in the adrenal gland. It binds to the melanocortin (MC) 2 receptors on the surface of the adrenal zona glomerulosa cells, producing cortisol.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 2
Correct
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To which of the following plasma proteins is T4 most bound in plasma?
Your Answer: Thyroxine-binding globulin
Explanation:Thyroxine-binding globulin, also known as TBG, is one of the three transport proteins responsible for carrying T4 and T3 through the circulatory system. It carries most of the T4 present in plasma, which it binds to strongly, shielding the hydrophobic hormones from the aqueous surroundings.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 3
Incorrect
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Mutation in RB can lead to the formation of which cancer?
Your Answer: Lung cancer
Correct Answer: Retinoblastoma
Explanation:Patients with a history of autosomal dominant familial retinoblastoma have at least one mutated copy of the RB gene. This predisposes the patient to develop retinoblastoma in one or both the eyes. Patients with a family history should be screened properly so that it can be detected and treated as early as possible.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 4
Incorrect
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Which one of the following is a cause of a soft second heart sound?
Your Answer: Mitral regurgitation
Correct Answer: Aortic stenosis
Explanation:Second heart sound (S2) forms the dub of lub-dub and is composed of components A2 and P2. •   loud: hypertension•   soft: AS•   fixed split: physiological split (normally occurs during inhalation), right bundle branch block, pulmonary stenosis, and atrial septal defect.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Incorrect
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The channel that coalesces the small pancreatic duct radicles before joining the common bile duct is known as the:
Your Answer: Duct of zymogen
Correct Answer: Duct of Wirsung
Explanation:The small ducts from the pancreas coalesce into a single duct known as the pancreatic duct or the duct of Wirsung. It usually joins the bile duct at the ampulla of Vater before entering the duodenum.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Incorrect
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Myocardial oxygen consumption is increased by:
Your Answer: A decrease in stroke volume
Correct Answer: An increase in after load
Explanation:Cardiac oxygen consumption is directly related to the amount of tension that develops in the ventricles. It is increased by an increased size of heart, increased afterload, increased contractility and increased heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Incorrect
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Which one of the following interventions has the least role in management of acne rosacea?
Your Answer: Laser therapy
Correct Answer: Low-dose topical corticosteroids
Explanation:Mild cases are often not treated at all, or are simply covered up with normal cosmetics and avoiding sun exposure. Therapy for the treatment of rosacea is not curative, and is best measured in terms of reduction in the amount of facial redness and inflammatory lesions. The two primary modalities of rosacea treatment are topical and oral antibiotic agents (including metronidazole and tetracyclines). Laser therapy may be appropriate for patients with prominent telangiectasia.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 8
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 9
Incorrect
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How does the proximal convoluted tubule excrete H+?
Your Answer: Via an accessory protein.
Correct 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 10
Incorrect
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The chemosensitive area in the medulla responds to:
Your Answer: Low hydrogen an high carbon dioxide
Correct Answer: High hydrogen and high carbon dioxide
Explanation:The chemosensitive area in the medulla responds mainly to high pH levels and carbon dioxide levels. Baroreceptors in the carotid and aortic body respond mainly to oxygen and carbon dioxide partial pressure in blood.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 11
Incorrect
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Where in the gastrointestinal tract are Brunner glands?
Your Answer: Oesophagus
Correct 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 12
Correct
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The ‘c’ wave in JVP corresponds more closely with:
Your Answer: Isovolumetric contraction
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections (peaks) and two downward deflections (troughs) have been described:The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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Which enzyme is responsible for the conversion of testosterone to dihydrotestosterone?
Your Answer: 17α-hydroxylase
Correct Answer: 5α-reductase
Explanation:The enzyme 5α-reductase synthesizes DHT from testosterone in the prostate, testes, hair follicles, and adrenal glands. This enzyme reduces the 4,5 double-bond of the testosterone. Relative to testosterone, DHT is much more potent as an agonist of the androgen receptor.
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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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Which of the atrial pressure changes represents the a-wave of the JVP
Your Answer: Rise in atrial pressure before tricuspid valve opens
Correct 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 15
Incorrect
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An 81-year-old male presented to the emergency department following a fall at home. He was diagnosed with osteoporosis about five years ago. He presently complains of significant low back pain. A lumbar spine X-ray was suggestive of a fractured lumbar vertebra. A subsequent MRI scan of the lumbosacral spine revealed a new L3 burst fracture with no evidence of cord compression. A neurosurgical consult was sought and conservative management was planned accordingly in the form of pain control, physiotherapy, and mobilization (as allowed by the pain). He also has been diagnosed with chronic renal disease (stage IV) with a creatinine clearance of 21ml/min, he was started on a Buprenorphine patch. Which of the following opioids would be safest to use for his breakthrough pain?
Your Answer: Diamorphine
Correct Answer: Oxycodone
Explanation:Oxycodone is a safer opioid to use in patients with moderate to end-stage renal failure.Active metabolites of morphine accumulate in renal failure which means that long-term use is contraindicated in patients with moderate/severe renal failure. These toxic metabolites can accumulate causing toxicity and risk overdose. Oxycodone is mainly metabolised in the liver and thus safer to use in patients with moderate to end-stage renal failure with dose reductions.Adverse effects:Constipation is the most common overall side effect. Others include: asthenia, dizziness, dry mouth, headache, nausea, pruritus, etc. Medications in renal failure:Drugs to be avoided in patients with renal failureAntibiotics: tetracycline, nitrofurantoinNSAIDsLithiumMetforminDrugs that require dose adjustment:Most antibiotics including penicillin, cephalosporins, vancomycin, gentamicin, streptomycinDigoxin, atenololMethotrexateSulphonylureasFurosemideOpioidsRelatively safe drugs:Antibiotics: erythromycin, rifampicinDiazepamWarfarin
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 16
Correct
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A 36 year old man arrives at the clinic complaining of pain and swelling of the left knee, ankles and right hallux. He has acute conjunctivitis, and dysuria. He suffered from an episode of gastroenteritis two weeks back. Clinical examination shows left Achilles tendonitis and right plantar fasciitis. Radiological examination reveals left sacroiliitis, with evidence of enthesitis, joint erosions and periostitis. HLA-B27 is positive. Which of the following is the most likely diagnosis?
Your Answer: Reiter’s syndrome
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 17
Incorrect
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Regarding the structure of the 3 pituitary glycoprotein hormones FSH, LH, and TSH, which of the following is true about the α- and β-subunits of each hormone?
Your Answer: The α-subunits are not interchangeable
Correct Answer: Maximal physiological activity occurs only on their combination
Explanation:Glycoprotein hormones (GPHs) are the most complex molecules that function as hormones. They each consist of two different subunits, α and β, which are non-covalently associated. The combination of these subunits results in an increase in their activity and β structure.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 18
Incorrect
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Around 30 patients have been admitted to the hospital following a suspected chemical attack in the city. The patients are extremely unwell, with symptoms of excessive salivation, lacrimation, diarrhoea, and emesis. Sarin gas was suspected as the most likely agent used in the attack. What is the mechanism of action of this chemical agent?
Your Answer: Sympathomimetic
Correct Answer: Inhibition of acetylcholinesterase
Explanation:Sarin acts by inhibiting acetylcholinesterase.Sarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesteraseSarin gas is a highly toxic synthetic organophosphorus compound which causes inhibition of the enzyme acetylcholinesterase. This results in high levels of acetylcholine (ACh).The effects of excessive ACh can be remembered by the mnemonic DUMBELLS:DiarrhoeaUrinationMiosis/muscle weaknessBronchorrhea/BradycardiaEmesisLacrimationSalivation/sweatingOrganophosphate insecticide poisoning:One of the effects of organophosphate poisoning is inhibition of acetylcholinesteraseFeatures can be predicted by the accumulation of acetylcholine (mnemonic = SLUD)SalivationLacrimationUrinationDefecation/diarrhoeacardiovascular: hypotension, bradycardiamiosis, muscle fasciculation.Organophosphate poisoning is treated with the anti-muscarinic atropine.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 19
Correct
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Conjugation of proteins to which polypeptide marks them for degradation?
Your Answer: Ubiquitin
Explanation:Ubiquitin is a small regulatory protein that affects proteins in many ways: it can mark them for degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions. Ubiquitination involves three main steps: activation, conjugation, and ligation,
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 20
Correct
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Which substance is produced by anterograde neurons?
Your Answer: Nitric oxide
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Classically in the peripheral nervous system, it diffuses from a presynaptic nerve ending to the post synaptic effecter cell which is mainly smooth muscle cells in the gastrointestinal, respiratory and urogenital tracts.
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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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Microfilaments exist in:
Your Answer: Cytosol
Correct Answer: All of the options
Explanation:Microfilaments, also called actin filaments, are filamentous structures in the cytoplasm of cells and form part of the cytoskeleton.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 22
Incorrect
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Somatostatin is responsible for?
Your Answer: Increased pancreatic secretions
Correct Answer: Decreased gastrin release
Explanation:Somatostatin is an inhibitory hormone secreted from the D cells of the Pancreatic Islets. It causes the inhibition of gastrin (decreasing stomach acid production), CCK (decreasing gallbladder motility), gastrin inhibitory peptide and secretin. Gastrin production is also inhibited by secretin, GIP, VIP, glucagon and calcitonin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 23
Incorrect
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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer: Myeloperoxidase converts br/i/cl to acids
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 24
Incorrect
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Arachidonic acid is converted to:
Your Answer: Phospholipase A2
Correct Answer: Prostaglandin H2
Explanation:The enzymes cyclooxygenase-1 and -2 (i.e. prostaglandin G/H synthase 1 and 2 {PTGS1 and PTGS2}) metabolize arachidonic acid to Prostaglandin G2 and prostaglandin H2.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 25
Incorrect
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Choose the correct statement regarding trabecular bone:
Your Answer: Also known as spongy bone
Correct Answer: All of the options are correct
Explanation:Trabecular, spongy or cancellous bone. It is located inside the cortical bone and makes up around 20% of all bone in the body. It is made of spicules or plates with a high surface to volume ratio, where many cells sit on the surface of the end plates. It receives its nutrients from the extracellular fluid (ECF), exchanging about 10 mmol of calcium every 24 hours.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 26
Incorrect
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Which of the following are true with regard to autosomal recessive disorders:
Your Answer: The parents of the affected offspring are generally unaffected healthy carriers
Correct Answer: All are true
Explanation:All are true for autosomal recessive disorders.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 27
Incorrect
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Myocardial contractility is improved by:
Your Answer: Hypoxia
Correct Answer: Caffeine
Explanation:Caffeine and other theophyllines breakdown cAMP and have a positive ionotropic effect on the heart. Drugs like quinidine, procainamide and conditions like hypoxia and hypercapnia decreases the contractility of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 28
Incorrect
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On a mountain the atmospheric pressure is 700 mmHg and the humidity close to zero, the partial pressure of oxygen is:
Your Answer: 110 mmHg
Correct Answer: 147 mmHg
Explanation:Natural air includes approximately 21% of oxygen. If humidity is zero, the partial pressure of oxygen is 700 × 21% = 147 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 29
Correct
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The thalamic nuclei that project over wide regions of the neocortex are:
Your Answer: Specific relay nuclei
Explanation:The thalamus is considered the relay station for sensory and motor stimuli. There are three basic types of thalamic nuclei: relay nuclei, association nuclei and non-specific nuclei. Relay nuclei receive very well defined inputs and project this signal to functionally distinct areas of the cerebral cortex. These include the nuclei that relay primary sensations and also the nuclei involved in feedback of cerebellar signals and basal gangliar output.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 30
Incorrect
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All of the following are associated with yellow nail syndrome except:
Your Answer: Pleural effusions
Correct Answer: Cardiomegaly
Explanation:Yellow nail syndrome is a very rare medical syndrome that includes pleural effusions, lymphedema (due to under development of the lymphatic vessels) and yellow dystrophic nails. Approximately 40% will also have bronchiectasis. It is also associated with chronic sinusitis and persistent coughing and it usually affects adults.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 31
Incorrect
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Cyclic AMP is formed from ATP via which enzyme
Your Answer: Protein Kinase A
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 32
Incorrect
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A patient has been diagnosed with multi-drug resistant tuberculosis and is currently bring treated with rifampicin, isoniazid, and pyrazinamide. He is commenced on streptomycin.Which among the following is the most likely neurological side-effect of streptomycin?
Your Answer: Optic nerve
Correct Answer: Vestibular damage
Explanation:Vestibular damage is a neurological side effect of streptomycin.Streptomycin is an aminoglycoside bactericidal antibiotic. It is used in the treatment of tularaemia and resistant mycobacterial infections.The most common neurological side-effect is vestibular damage leading to vertigo and vomiting. Cochlear damage is less frequent and results in deafness. Other side-effects include rashes, angioneurotic oedema, and nephrotoxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 33
Incorrect
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A 35 year old sales representative presents with severe pain going down her neck and right arm. She admits that this pain is worse on sitting and driving for long periods. Past history is significant for two previous road traffic accidents. Examination reveals weakness and sensory loss over C5/C6 nerve distribution. There is pain with neck movement and particularly extension. Which of the following investigations would be the most helpful in this case?
Your Answer: Plain X-rays
Correct Answer: MRI scan of the cervical spinal cord
Explanation:Cervical radiculopathy is usually due to compression or injury to a nerve root by a herniated disc or degenerative changes. Levels C5 to T1 are the most commonly affected. It is usually, but not always, accompanied by cervical radicular pain, a sharp and shooting pain that travels from the neck and down the upper limb and may be severe. This needs to be differentiated from pain referred from the musculoskeletal (somatic) structures in the neck, which may be aching rather than sharp, and is more severe in the neck than in the upper limb. The neurological signs of cervical radiculopathy depend on the site of the lesion. The patient may have motor dysfunction, sensory deficits or alteration in tendon reflexes. While pain is a common presenting symptom, not all radiculopathies are painful (i.e. only motor deficits may be obvious). CT scanning cannot accurately demonstrate the commonest cause for cervical radiculopathy (disc herniation) without myelography, which requires hospital admission, lumbar puncture and the use of contrast. In patients with cervical radiculopathy, MRI is the imaging technique of choice for the detection of root compression by disc herniation and osteophytes. MRI allows the nerve roots to be directly visualised. Nerve conduction studies are also useful in determining the nerve roots that are involved.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 34
Incorrect
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Activation of baroreceptor reflex involves:
Your Answer: None of the above
Correct Answer: Short term regulation of systemic blood pressure
Explanation:Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 35
Incorrect
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In a newly diagnosed acromegaly patient, which of the following would you not expect to find?
Your Answer: Carpal tunnel syndrome
Correct Answer: Hypohidrosis
Explanation:Features of acromegaly may include:
- Soft tissue swelling visibly resulting in enlargement of the hands, feet, nose, lips and ears, and a general thickening of the skin
- Soft tissue swelling of internal organs, notably the heart with associated weakening of its muscularity, and the kidneys, vocal cords (resulting in a characteristic thick, deep voice and slowing of speech)
- Generalized expansion of the skull at the fontanelle, frontal bossing, prognathism with associated macroglossia (enlargement of the tongue) and teeth spacing.
- Hypertrichosis, hyperpigmentation and hyperhidrosis (not hypohidrosis) may occur in these patients as well as carpal tunnel syndrome and impotence.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 36
Incorrect
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Which one of the following nerve fibers is involved in proprioception?
Your Answer: A δ fiber
Correct Answer: An α fiber
Explanation:Proprioception, also known as kinaesthesia, is the sense through which humans perceive their own position and movements. α nerve fibers are specifically involved in transmitting proprioception stimuli.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 37
Correct
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Where is Vitamin B 12 absorbed?
Your Answer: Terminal ileum
Explanation:Protein-bound vitamin B12 must be released from the proteins by the action of digestive proteases in both the stomach and small intestine. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B12. B12 must be attached to Intrinsic Factor (IF) for it to be efficiently absorbed, as receptors on the enterocytes in the terminal ileum of the small bowel only recognize the B12-IF complex; in addition, intrinsic factor protects the vitamin from catabolism by intestinal bacteria.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 38
Incorrect
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A 62 year old man arrives at the clinic with a history of cough and intermittent haemoptysis for the last 3 months. He has a 50 pack year smoking history and is currently waiting for bronchoscopy to assess a left lower lobe collapse. The patient also has a marked muscle weakness and wasting of proximal muscles of his shoulders and pelvic girdle. His wife states that lately he has been unable to eat solids. Which of the following statements would be true regarding this scenario?
Your Answer: He almost certainly has adenocarcinoma of the lung
Correct Answer: He may have a photosensitive facial rash
Explanation:The patient has presented with signs of small cell lung cancer. The associated proximal muscle weakness is most probably due to dermatomyositis which occurs as a paraneoplastic syndrome associated with lung carcinoma. In most cases, the first symptom is a distinctive skin rash on the face, eyelids, chest, nail cuticle areas, knuckles, knees or elbows. The rash is patchy and usually a bluish-purple colour. Corticosteroids are helpful in the management of the cutaneous changes and muscle weakness.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 39
Incorrect
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Histamine, acetylcholine and gastrin act by way of which second messengers in the release of acid by parietal cells:
Your Answer: Camp
Correct Answer: A and D
Explanation:Acetylcholine, Histamine and Gastrin receptors are located on the basolateral membrane of the parietal cell and control its activity. Stimulation of these receptors modulates the levels of protein kinases in the cell and brings about the changes from a resting to stimulated structure. Protein kinase catalyses conversion of ATP to cyclic AMP which activates the proton pump. Calcium ions increase gastric acid secretion elicited by gastrin released through a vagal mechanism, and also by a direct effect on parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 40
Incorrect
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The Cellular Theory of Ageing involves?
Your Answer: Gene regulation
Correct Answer: Loss of telomeres
Explanation:Cellular theories of aging propose that human aging is the result of cellular aging, whereby an increasing proportion of cells reach senescence, a terminal stage at which cells will cease to divide. This will limit the body’s ability to regenerate and to respond to injury or stress. Telomeres are bits of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause DNA to abnormally function. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging.
Other theories include:
- The Free Radical Theory: Implicates the gradual accumulation of oxidative cellular damage as a fundamental driver of cellular aging. This theory has evolved over time to emphasize the role of free radical induced mitochondrial DNA (mtDNA) mutations and the accumulation of mtDNA deletions. Given the proximity of mtDNA to the electron transport chain, a primary producer of free radicals, it postulates that the mutations would promote mitochondrial dysfunction and concomitantly increase free radical production in a positive feedback loop. It is known that diet, lifestyle, drugs (e.g. tobacco and alcohol) and radiation etc., are all accelerators of free radical production within the body.
- Error theory: based on the idea that errors can occur in the transcription of the synthesis of DNA. These errors are perpetuated and eventually lead to systems that do not function at the optimum level. The organism’s aging and death are attributable to these events (Sonneborn, 1979).
- The Cross-Linking Theory: also referred to as the Glycosylation Theory of Aging. In this theory it is the binding of glucose (simple sugars) to protein, (a process that occurs under the presence of oxygen) that causes various problems. Once this binding has occurred the protein becomes impaired and is unable to perform as efficiently. Living a longer life is going to lead to the increased possibility of oxygen meeting glucose and protein and known cross-linking disorders include senile cataract and the appearance of tough, leathery and yellow skin.
- The Neuroendocrine Theory First proposed by Professor Vladimir Dilman and Ward Dean MD, this theory elaborates on wear and tear by focusing on the neuroendocrine system. This system is a complicated network of biochemicals that govern the release of hormones which are altered by the walnut sized gland called the hypothalamus located in the brain. The hypothalamus controls various chain-reactions to instruct other organs and glands to release their hormones etc. The hypothalamus also responds to the body hormone levels as a guide to the overall hormonal activity. But as we grow older the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, as we age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading
- The Membrane Theory of Aging:Â According to this theory it is the age-related changes of the cell’s ability to transfer chemicals, heat and electrical processes that impair it. As we grow older the cell membrane becomes less lipid (less watery and more solid). This impedes its efficiency to conduct normal function and in particular there is a toxic accumulation
- The Decline Theory: The mitochondria are the power producing organelles found in every cell of every organ. Their primary job is to create Adenosine Triphosphate (ATP) and they do so in the various energy cycles that involve nutrients such as Acetyl-L-Carnitine, CoQ10 (Idebenone), NADH and some B vitamins etc. Enhancement and protection of the mitochondria is an essential part of preventing and slowing aging. Enhancement can be achieved with the above mention nutrients, as well as ATP supplements themselves.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 41
Incorrect
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The following determines the strength of contraction
Your Answer: Resting membrane potential
Correct Answer: Plateau phase
Explanation:The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 42
Incorrect
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Which of the following is true with regard to the acini?
Your Answer: Peripheral zone is least oxygenated
Correct Answer: The central zone (Zone III) is the least oxygenated
Explanation:The acini are divided into zone I (periportal), zone II (transition zone), and zone III (pericentral). Cells located close to the portal triad or peripheral zone which consist of an arteriole from the hepatic artery are the most oxygenated cells. Cells in the central zone (III) are least oxygenated and mainly receive blood supply from the central vein which is a branch of hepatic vein.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 43
Incorrect
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A 23 year old male patient presents with urethritis for the last 2 weeks that has not responded to antibiotics. Lately he has developed an onset of new range of symptoms that are linked to his HLA B27 positivity. Which of the following signs is not related to Reiter's syndrome?
Your Answer: Tenderness over the planter surface of the ankle
Correct Answer: A mild fever with a generalised macular rash
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. Dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum)
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 44
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: Spironolactone
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 45
Incorrect
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Which of the following pairs are correct concerning arteriolar tone?
Your Answer: Myogenic control: vascular smooth muscle responds to changes in pressure
Correct Answer: Hormonal control: catecholamines affect the adrenergic receptors of the vascular smooth muscle
Explanation:Catecholamines released from the adrenal medulla act on the noradrenergic receptors of the vascular smooth muscles. In the skeletal muscles and liver it causes vasodilation whilst it causes vasoconstriction in the rest of the blood vessels of the body.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 46
Incorrect
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A 70-year-old male with advanced COPD currently on treatment with salbutamol (as required) presents for review. After a complete history and examination, you conclude that he requires to be stepped up in his inhalational therapy. The decision to add tiotropium bromide to his regime was taken. Which of the following best describe the mechanism of action of tiotropium?
Your Answer: It is a long-acting β2-agonist
Correct Answer: It is a long-acting anticholinergic agent
Explanation:Tiotropium is a specific long-acting antimuscarinic agent indicated as maintenance therapy for patients with COPD (chronic obstructive pulmonary disease). It should be used cautiously in patients with narrow-angle glaucoma, prostatic hyperplasia or bladder neck obstruction.The most frequently encountered adverse effects of tiotropium include pharyngitis, bronchitis, sinusitis, dry mouth, cough, and headaches. Paradoxical bronchospasm may also occur as a rare side-effect. Dry mouth occurs in up to 14% of patients taking tiotropium, in keeping with its anticholinergic profile. Rarer side-effects include tachycardia, blurred vision, urinary retention, and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 47
Incorrect
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Which of the following takes place during fasting
Your Answer: Segmentation and mixing
Correct Answer: Migrating motor complex
Explanation:Migrating motor complexes (MMC) are waves of electrical activity that sweep through the intestines in a regular cycle during fasting. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 48
Incorrect
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Concerning S3, which of the following statements is INCORRECT?
Your Answer: Normal in children
Correct Answer: Coincide with atrial contraction
Explanation:A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 49
Incorrect
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The Afferent neuron that supplies all sensory elements of the muscle spindle is what type of sensory neuron?
Your Answer: IIb
Correct Answer: Ia
Explanation:Muscle spindle is supplied by both sensory and motor nerves. Sensory supply is Type Ia fibers whereas motor supply is gamma motor neurone.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 50
Incorrect
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An 18 year old girl presents with short history of marked, right hip pain and an associated limp. She has a history of acute lymphoblastic leukaemia for which she completed treatment for last six months.
Your Answer: Gout
Correct Answer: Avascular necrosis of the femoral head
Explanation:Avascular necrosis (AVN) of the femoral head is a pathological process that results from disruption of the blood supply to the bone and occurs most commonly in the femoral epiphysis. Patients usually present with pain and limited joint motion. The mechanism involves impaired circulation to a specific area that ultimately becomes necrotic. AVN is most frequently associated with high doses of oral and intravenous corticosteroids and prolonged duration of therapy. Cancer patients receiving chemotherapy are usually also treated with corticosteroids.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
