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Question 1
Correct
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Which is true of the citric acid cycle?
Your Answer: Involves a series of reactions where oxaloacetate is regenerated
Explanation:The cycle consumes acetate (in the form of acetyl-CoA) and water, reduces NAD+ to NADH, and produces carbon dioxide as a waste by-product. The NADH generated by the citric acid cycle is fed into the oxidative phosphorylation (electron transport) pathway. At the end of each cycle, the four-carbon oxaloacetate has been regenerated, and the cycle continues. The net result of these two closely linked pathways is the oxidation of nutrients to produce usable chemical energy in the form of ATP. Acetyl-CoA, is the starting point for the citric acid cycle and in eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion. Though the Krebs cycle does not directly require oxygen, it can only take place when oxygen is present because it relies on by-products and is therefore an aerobic process.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 2
Incorrect
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Vasodilatation of coronary arteries is caused by:
Your Answer: Hypothermia
Correct Answer: Hypoxia
Explanation:The heart is highly metabolically active and boasts the highest oxygen consumption by mass of any organ. This demand for oxygen is met by the coronary circulation, which is responsible for delivering blood to the myocardium and represents approximately 5% of cardiac output. Vasodilation may be due to the local effect of hypoxia on coronary vessels, or local metabolic vasodilation, or the activation of β-adrenoceptors or some combination of these mechanisms.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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Which of the following is correct regarding lead poisoning?
Your Answer: Causes a peripheral neuropathy due to demyelination
Explanation:Lead can be absorbed through the skin and by inhalation. It is associated with iron deficiency and a microcytic anaemia. The most common gastrointestinal symptoms are abdominal colic and constipation.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 4
Correct
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Compact/cortical bone makes up
Your Answer: The outer layer of most bones and accounts for 80% of bone in the body
Explanation:Cortical, lamellar, or compact bone, is more dense than spongy bone and it forms the rigid, outer layer of bones, also called cortex. It consists of packed osteons, with a central osteonic canal surrounded by concentric rings. Spaces called lacunae are filled with osteocytes, and channels called canaliculi go from the lacunae to the osteonic canal. The strength of cortical bone allows it to support the body and protect organs. It also stores different elements, such as calcium.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 5
Incorrect
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A 60 year old male presents with thickened patches of skin over his knuckles and extensor surfaces that are consistent with Gottron's papules. Results reveal an elevated creatine kinase. Diagnosis of dermatomyositis is suspected. Which of the following autoantibody is most specific for this condition?
Your Answer: Anti-scl-70 antibodies
Correct Answer: Anti-Mi-2 antibodies
Explanation:Anti–Mi-2 antibodies are highly specific for dermatomyositis, but sensitivity is low; only 25% of patients with dermatomyositis demonstrate these antibodies. A positive antinuclear antibody (ANA) finding is common in patients with dermatomyositis, but is not necessary for diagnosis. Anti-Jo-1 antibodies are mostly associated with polymyositis. Anti Scl-70 antibodies and anti centromere antibodies are most commonly found in systemic scleroderma.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 6
Correct
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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 7
Correct
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Which of the following cancers is responsible in producing osteoblastic bone metastases instead of osteolytic?
Your Answer: Prostate adenocarcinoma
Explanation:Osteoblastic (or sclerotic) bone metastases, characterized by deposition of new bone, present in prostate cancer, carcinoid, small cell lung cancer, Hodgkin lymphoma or medulloblastoma.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 8
Incorrect
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Which vitamin is found in NAD and NADP?
Your Answer: Vitamin B1
Correct Answer: Vitamin B3
Explanation:In organisms, NAD can be synthesized from simple building-blocks (de novo) from the amino acids tryptophan or aspartic acid. In an alternative fashion, more complex components of the coenzymes are taken up from food as the vitamin called niacin (vitamin B3)
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This question is part of the following fields:
- Haematology
- Medicine
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Question 9
Correct
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Which of the following is NOT a component of bile?
Your Answer: Unconjugated bilirubin
Explanation:The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts (electrolytes).
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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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A 48-year-old male with a history of bipolar disorder presents with acute confusion. In-transit to hospital he had a generalized seizure which terminated spontaneously after around 30 seconds. On arrival to the emergency department, his GCS is 14/15 and he is noted to have a coarse tremor. Suspecting a diagnosis of lithium toxicity, intravenous access is obtained, a blood sample was drawn for investigations and a saline infusion is started. The blood investigations revealed:Lithium level: 4.2 mmol/lNa+: 136 mmol/lK+: 4.6 mmol/lUrea: 8.1 mmol/lCreatinine: 99 µmol/lBicarbonate: 18 mmol/lWhat is the most appropriate management for the patient?
Your Answer: Intravenous bicarbonate
Correct Answer: Arrange haemodialysis
Explanation:The presentation of the patient is typical of chronic lithium toxicity (due to the presence of mainly neurological manifestations). Additional to the blood investigations mentioned, urine analysis, electrolyte levels, and renal function should also be performed. A low urine Anion gap and a low urine specific gravity are highly suggestive of lithium toxicity.ECG obtained in this patient is likely to show: nonspecific, diffuse ST segment depression with T wave inversion.Acute lithium toxicity presents with more GI manifestations while, the clinical features of chronic lithium toxicity are mainly neurological and can include:Coarse tremors (fine tremors are seen in therapeutic levels), hyperreflexia, acute confusion, seizures, and coma.The management of lithium toxicity is as follows:Immediate GI decontamination with gastric lavage (in case of acute intoxication)Saline Administrations: the goal of saline administration is to restore GFR, normalize urine output and enhance lithium clearance.Haemodialysis remains the mainstay treatment for lithium toxicity as lithium is readily dialyzed because of water solubility, low volume of distribution, and lack of protein binding.The Extracorporeal Treatments in Poisoning Workgroup (EXTRIP Workgroup) recommendations for dialysis (extracorporeal treatment) in lithium toxicity include:• Impaired kidney function and lithium levels > 4.0 mEq/L• Decreased consciousness, seizures, or life-threatening dysrhythmias, regardless of lithium levels• Levels are > 5.0 mEq/L, significant confusion is noted, or the expected time to reduce levels to < 1.0 mEq/L is more than 36 hoursAs post-dialysis rebound elevations in lithium levels have been documented, continuous veno-venous hemofiltration (CVVH) has been advocated.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 11
Correct
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Bone marrow barrier is important to:
Your Answer: Allow mature red blood cells to pass into circulation
Explanation:The blood vessels of the bone marrow constitute a barrier, inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane proteins, such as aquaporin and glycophorin, that are required to attach to and pass the blood vessel endothelium.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 12
Correct
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The following are synthesized in the liver EXCEPT?
Your Answer: Cholecystokinin
Explanation:The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow. The liver also produces albumin, the most abundant protein in blood serum and angiotensinogen. Cholecystokinin, previously called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 13
Correct
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Question 14
Correct
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Which neuron secretes glutamate as its neurotransmitter?
Your Answer: A delta and C pain fibers
Explanation:A delta and C fibers use glutamate as their primary neurotransmitter where it acts as a fast acting localized neurotransmitter.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Correct
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The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 16
Incorrect
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The process whereby bacterial products interact with plasma factors and cells to produce agents that attract neutrophils to an infected area is called:
Your Answer: Diapedesis
Correct Answer: Chemotaxis
Explanation:During an inflammatory process many cytokines are produced that act as chemokines to attract neutrophils to the site of inflammation. These include bacterial products, IL-8, C5a and LTB4.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 17
Incorrect
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During strenuous exercise the following arterial change can take place in a fit athlete:
Your Answer: Both oxygen and carbon dioxide will change
Correct Answer: No change takes place
Explanation:The changes which occur in arterial pH, PO2 and PCO2 values during exercise are usually small. Arterial PO2 often rises slightly because of hyperventilation although it may eventually fall at high work rates. During vigorous exercise, when sufficient oxygen for flux through the Krebs cycle is not available, the increased reliance on glycolysis results in increased accumulation of lactic acid, which initially leads to an increase in PaCO2 . However, this is counteracted by the stimulation of ventilation and as a result PaCO2 is decreased. This provides some respiratory compensation for further lactic acid production and prevents a decline in blood pH, which remains nearly constant during moderate exercise.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 18
Correct
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Which cell secretes parathyroid hormone?
Your Answer: Chief cells
Explanation:Parathyroid chief cells, also known as parathyroid principal cells or parathyroid cells, are the most prevalent type of cell in the parathyroid gland and the only ones present at birth. They secrete parathyroid hormone (PTH).
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 19
Correct
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All of the following are associated with yellow nail syndrome except:
Your 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 20
Incorrect
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Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer: Mg
Correct Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Correct
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Bile acids will be prevented from being absorbed by resection of which part of the gastrointestinal tract?
Your Answer: Ileum
Explanation:Bile acids (also called bile salts) are produced in the liver, secreted into the biliary system, stored in the gallbladder and are released after meals stimulated by cholecystokinin. They are important for the digestion and absorption of fats (lipids) in the small intestine. Usually over 95% of the bile acids are absorbed in the terminal ileum and are taken up by the liver and resecreted.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 22
Incorrect
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Cyclic AMP activates the following enzyme
Your Answer: Adenylyl cyclase
Correct Answer: Protein Kinase A
Explanation:Cyclic AMP works by activating protein kinase A (PKA, or cAMP-dependent protein kinase). Protein kinase A can also phosphorylate specific proteins that bind to promoter regions of DNA, causing increases in transcription.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 23
Correct
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Concerning surface anatomy, where is the aortic valve found?
Your Answer: Situated in the left third intercostal space underneath the sternum
Explanation:The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Correct
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Which of the following takes place during fasting
Your 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 25
Correct
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Question 26
Incorrect
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Role of bile salts in digestion of fats include
Your Answer: Micelle formation and absorption
Correct Answer: Reduce surface tension, emulsification and transportation
Explanation:Bile acts to some extent as a surfactant reducing surface tension, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend to aggregate around droplets of lipids (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic sides facing outwards. The hydrophilic sides are negatively charged, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles.
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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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A 45 year old man, known case of hypothyroidism, presents with a 3 month history of pain and stiffness in the joints of his hands and feet. He also complains of dyspnoea occurring for the past 6 weeks. On examination there is a right pleural effusion and swollen hand joints. The clinician makes a diagnosis of rheumatoid arthritis. Which of the following is most characteristic of a rheumatoid pleural effusion?
Your Answer: It is a transudate
Correct Answer: It has a low glucose level
Explanation:The typical “rheumatoid effusion” is a sterile exudative fluid with low pH (<7.3), low glucose (700 IU). It should initially be treated with NSAIDs. Decortication should be reserved in patients with thickened pleura who have symptomatic dyspnoea.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 28
Correct
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Translation usually begins at which codon?
Your Answer: AUG
Explanation:The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and the most common start codon is AUG.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 29
Incorrect
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In most somatic cells telomeres progressively shorten as:
Your Answer: The host ages
Correct Answer: The cell divides
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. A somatic cell is any biological cell forming the body of an organism, other than a gamete, germ cell, gametocyte or undifferentiated stem cell. i.e. liver cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 30
Correct
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A 65-year-old man, after suffering from a pathological rib fracture, complains of recurrent infection. Bone marrow aspiration revealed a calcium level of 3.9 mmol/l and alkaline phosphatase level of 160u/l. What type of cell would be found in abundance in the marrow spear?
Your Answer: Plasma cells
Explanation:Multiple myeloma or plasma cell myeloma, is a cancer of plasma cells, responsible for producing antibodies. It often, presents early with no symptoms followed by bone pain and pathological fractures (metastases), raised calcium levels, bleeding, frequent infections, and anaemia. It usually occurs around the age of 61 and is more common in men than women.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 31
Correct
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In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should be made at:
Your Answer: 200 J
Explanation:Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. If the patient is in Ventricular tachycardia (VT) or ventricular fibrillation (VF) on the monitor, immediately apply the pads and shock the patient with 120-200 Joules on a biphasic defibrillator or 360 Joules on a monophasic defibrillator.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 32
Correct
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All valves are closed in which phase of the cardiac cycle?
Your Answer: Isovolumetric relaxation
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Correct
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Which of the following cells will degranulate and release histamine when binding to IgE?
Your Answer: Basophils
Explanation:Basophils have protein receptors on their cell surface that bind IgE, an immunoglobulin involved in microparasite defence and allergy. When activated, basophils degranulate to release histamine, proteoglycans (e.g. heparin and chondroitin), and proteolytic enzymes (e.g. elastase and lysophospholipase).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 34
Correct
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A 22-year-old female comes to you for counselling regarding the initiation of combined oral contraceptive pill. Which of the following statements is correct?
Your Answer: She will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill
Explanation:The true statement among the given options is that she will still be protected against pregnancy if she takes amoxicillin for a lower respiratory tract infection while on the combined pill.Other than enzyme-inducing antibiotics such as rifampicin, antibiotics do not reduce the efficacy of the combined oral contraceptive pill.It was previously advised that barrier methods of contraception should be used if taking an antibiotic while using the contraceptive pill, due to concerns that antibiotics might reduce the absorption of the pill. This is now known to be untrue. However, if the absorptive ability of the gut is compromised for another reason, such as severe diarrhoea or vomiting, or bowel disease, this may affect the efficacy of the pill.The exception to the antibiotic rule is that hepatic enzyme-inducing antibiotics such as rifampicin and rifaximin do reduce the efficacy of the pill. Other enzyme-inducing drugs, such as phenytoin, phenobarbital, carbamazepine or St John’s Wort can also reduce the effectiveness of the pill.Other options:The combined pill is often prescribed for women with heavy periods as it can make them lighter and less painful. There is no evidence that women on the combined pill put on any significant weight, although they may experience bloating at certain times in the course. Women on the pill require monitoring of their blood pressure. There are multiple different types of combined pills.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 35
Incorrect
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The V wave in the jugular pulse is caused by:
Your Answer: Ventricular filling
Correct Answer: Atrial filling
Explanation:The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.
The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 36
Incorrect
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Which of the following cells are attracted to the surface of endothelium by selectins?
Your Answer: Lymphocytes
Correct Answer: Neutrophils
Explanation:Selectins are expressed on the surface of the endothelium. P selectins are released from weibel-palade bodies and E selectins are induced by cytokines (TNF and IL-1). They bind to receptors on the neutrophils called saiyl lewis X.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 37
Correct
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A 28 year old woman presents with painful genital ulceration. She reports that these attacks have been recurrent over the past 4 years. She has been treated previously with oral acyclovir but this has had little effect on the duration of her symptoms. Over the past year, she has noticed almost weekly attacks of mouth ulcers that heal slowly. Past medical history is significant for treatment of thrombophlebitis two years ago. Which of the following is the most likely diagnosis?
Your Answer: Behcet's syndrome
Explanation:Behçet disease is a rare vasculitic disorder that is characterized by a triple-symptom complex of recurrent oral aphthous ulcers, genital ulcers, and uveitis. The systemic manifestations can be variable. Ocular disease has the greatest morbidity, followed by vascular disease generally from active vasculitis. Cutaneous manifestations can occur in up 75% of patients with Behcet disease and can range from acneiform lesions, to nodules and erythema nodosum. GI manifestations can be severe. Differentiating Behçet disease from active inflammatory bowel disease can be clinically difficult. Herpes would have ideally responded to acyclovir. Sarcoidosis does not have genital and oral ulcerations.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 38
Incorrect
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Why does arterial blood pressure drop during pregnancy?
Your Answer: Oestrogen relaxes vascular smooth muscle
Correct Answer: Progesterone relaxes vascular smooth muscle
Explanation:Progesterone relaxes vascular smooth muscle thus resulting In a decrease in total peripheral resistance. This accounts for the increase in the cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 39
Incorrect
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The following is true in relation to coronary venous drainage?
Your Answer:
Correct Answer: Most venous return ultimately drains into right atrium via the coronary sinus
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 40
Incorrect
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Cytochrome p450 enzymes expressed in hepatocytes serve to?
Your Answer:
Correct Answer: Facilitate oxidations or hydrolysis of drugs.
Explanation:Cytochrome p 450 are a family of proteins involved in drug metabolism which accounts for about 75% of the total metabolism. Most drugs are deactivated directly or by facilitated excretion from the body.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 41
Incorrect
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Most of the venous blood returns to the heart through the:
Your Answer:
Correct Answer: Coronary sinus and anterior cardiac veins
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins which drain into the right atrium.
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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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A 75 year old man presented to hospital after suffering a stroke. The doctor admitted him and advised of the Barthel score index. During rehabilitation, which one of the following limitations are best described by Barthel score index?
Your Answer:
Correct Answer: Floor and ceiling effects
Explanation:Barthel scoring has floor and ceiling effects which is the most widely recognised limitation. Floor effect means that the patient who is bed bound can score initially low, whereas the ceiling effect shows that despite being bed bound, a patient can achieve a maximum score i.e. 100. The test is easy to perform and correlates well with other prognostic scales.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 43
Incorrect
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A 43 year old female presents with an array of symptoms including weakness, lethargy, dysphagia, dry mouth, gritty sensation in her eyes and increased photosensitivity. In order to confirm the suspected diagnosis, which of the following tests should be performed?
Your Answer:
Correct Answer: Labial gland biopsy
Explanation:To confirm the diagnosis, especially in patients with negative anti-Ro or anti-La antibodies, labial gland biopsy is done. In performing a labial biopsy, the surgeon typically makes a shallow 1/2 inch wide incision on either side of the inner lip after numbing the area with a local anaesthetic. Schirmer’s test determines whether the eye produces enough tears to keep it moist. This test can be done for ocular symptoms of Sjogren syndrome but is of no diagnostic importance as it can be positive with many other diseases.
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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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Afferent fibers from the baroreceptors of the great arteries form branches of which cranial nerves?
Your Answer:
Correct Answer: Glossopharyngeal and vagus nerves
Explanation:The receptors of the carotid sinus are innervated by the carotid sinus nerve, a branch of the glossopharyngeal nerve. The aortic arch receptors located in the arch of the aorta are innervated by the aortic depressor nerve, a branch of the vagus nerve.
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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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A study is carried out to assess the efficacy of a rapid urine screening test developed to detect Chlamydia. The total number of people involved in the study were 200. The study compared the new test to the already existing NAAT techniques. The new test was positive in 20 patients that were Chlamydia positive and in 3 patients that were Chlamydia negative. For 5 patients that were Chlamydia positive and 172 patients that were Chlamydia negative the test turned out to be negative. Choose the correct value regarding the negative predictive value of the new test:
Your Answer:
Correct Answer: 172/177
Explanation:The definition of negative predictive value is the probability that the individuals with truly negative screening test don’t have Chlamydia. The equation is the following: Negative predictive value = Truly negative/(truly negative + false negative) = 172 / (172 + 5) = 172 / 177
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 46
Incorrect
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Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:
Your Answer:
Correct Answer: Weakening of the troponin i interaction with actin
Explanation:At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 47
Incorrect
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Erythropoietin is synthesized by which cells of the nephron?
Your Answer:
Correct Answer: Tubular interstitial cells
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:
- Medicine
- Renal
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Question 48
Incorrect
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The areas of extensive series of sarcoplasmic folds known as intercalated discs always occur at what portion of the muscle fiber?
Your Answer:
Correct Answer: Z lines
Explanation:The muscle fibers of the heart branch and interdigitate, but one complete unit is surrounded by a cell membrane. The place where one muscle fiber abuts the other, the cell membrane of both the fibers run parallel to each other through a series of extensive folds. These areas always occur on the Z lines and are known as intercalated discs.
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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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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:
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 50
Incorrect
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The initial rapid depolarization in the action potential of cardiac muscle cells is due to:
Your Answer:
Correct Answer: Opening of voltage-gated Na+ channels
Explanation:The initial depolarization of the action potential in a cardiac muscle cell is due to the sodium current generated by opening of the voltage gated sodium channels leading to an influx of sodium ions into the cell and raising the membrane potential towards threshold.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 51
Incorrect
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When during the cell cycle do the centrioles replicate?
Your Answer:
Correct Answer: G1 phase
Explanation:During G1 phase the cell will prepare for cell division. All the organelles will start to duplicate in this phase and the cell will begin to grow whilst proteins are also synthesized.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 52
Incorrect
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What is the function of gap junctions?
Your Answer:
Correct Answer: Diffusion of small molecules between neighbouring cells
Explanation:Gap junctions are a specialized intercellular connection between a multitude of cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regulated gate between cells.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 53
Incorrect
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With regards to the deiodinases, where would you find D1?
Your Answer:
Correct Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 54
Incorrect
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An important hormone controlling the differentiation of monocytes to osteoclasts, by inhibiting the RANKL/ RANK interaction is called?
Your Answer:
Correct Answer: Osteoprotegerin
Explanation:Osteoprotegerin, also known as osteoclastogenesis inhibitory factor (OCIF) is a glycoprotein that acts as a cytokine receptor. It works as a decoy receptor for the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoclast differentiation factor, thus inhibiting the differentiation of osteoclasts, which are capable of resorbing bone. Osteoprotegerin has been proposed as a therapeutic agent for osteoporosis.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 55
Incorrect
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A 75-year-old man has presented to the clinic with a complaint of disturbed sleep. The physician has prescribed temazepam. Which of the following best describes the mechanism of action of this drug?
Your Answer:
Correct Answer: Enhances the effect of gamma-aminobutyric acid
Explanation:Temazepam is an orally available benzodiazepine used in the therapy of insomnia. The soporific activity of the benzodiazepines is mediated by their ability to enhance gamma-aminobutyric acid (GABA) mediated inhibition of synaptic transmission through binding to the GABA-A receptor.The recommended initial dose for insomnia is 7.5 mg before bedtime, increasing as needed to a maximum dose of 30 mg. The most common side effects of temazepam are dose-related and include daytime drowsiness, lethargy, ataxia, dysarthria, and dizziness.Tolerance develops to these side effects, but tolerance may also develop to the effects on insomnia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 56
Incorrect
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Which one of the following interventions has the least role in management of acne rosacea?
Your Answer:
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 57
Incorrect
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Cells mediating innate immunity include:
Your Answer:
Correct Answer: Natural killer cells
Explanation:Natural killer cells have features of both innate and adaptive immunity. They play an important part in defence against tumours and viruses. They are non specific and do not generate immunological memory
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This question is part of the following fields:
- Immunology
- Medicine
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Question 58
Incorrect
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A 39 year old woman with a history of rheumatoid arthritis has recently been switched from methotrexate to leflunomide. Monitoring of full blood count and LFTs has been carried out. Which of the following parameters should also be monitored in this case?
Your Answer:
Correct Answer: Blood pressure
Explanation:Blood pressure should be routinely measured as leflunomide may cause hypertension and thus an increase in BP. It doesn’t cause changes in blood sugar levels, peak expiratory flow rate or haematuria.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 59
Incorrect
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Which of the following statements regarding influenza virus is correct?
Your Answer:
Correct Answer: Influenza is a RNA virus
Explanation:The Orthomyxoviruses are a family of RNA viruses that includes six genera: Influenza virus A, Influenza virus B, Influenza virus C, Isavirus, Thogotovirus and Quaranjavirus.The mechanism of the evolutionary force of antigenic shift allows influenza viruses to exchange genes with strains that infect different species. Under this mechanism, a human influenza virus could exchange genes with an avian strain, and that is how pandemic strains arise.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 60
Incorrect
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Where is the majority of Mg2+ absorbed?
Your Answer:
Correct Answer: Thick ascending limb of loop of Henle.
Explanation:Although the majority of the filtered magnesium is reabsorbed within the ascending loop of Henle, it is now recognized that the distal tubule also plays an important role in magnesium conservation.
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This question is part of the following fields:
- Medicine
- Renal
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SESSION STATS - PERFORMANCE PER SPECIALTY
