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Question 1
Incorrect
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Regarding the coagulation cascade, Factor VII:
Your Answer: Is a cytokine
Correct Answer: Is a serine protease
Explanation:Factor VII (FVII) is a zymogen for a vitamin K-dependent serine protease essential for the initiation of blood coagulation. It is synthesized primarily in the liver and circulates in plasma. Within the liver, hepatocytes are involved in the synthesis of most blood coagulation factors, such as fibrinogen, prothrombin, factor V, VII, IX, X, XI, XII, as well as protein C and S, and antithrombin, whereas liver sinusoidal endothelial cells produce factor VIII and von Willebrand factor.
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This question is part of the following fields:
- General
- Physiology
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Question 2
Correct
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Post-total gastrectomy, there will be a decreased production of which of the following enzymes?
Your Answer: Pepsin
Explanation:Pepsin is a protease that is released from the gastric chief cells and acts to degrade proteins into peptides. Released as pepsinogen, it is activated by hydrochloric acid and into pepsin itself. Gastrin and the vagus nerve trigger the release of pepsinogen and HCl when a meal is ingested. Pepsin functions optimally in an acidic environment, especially at a pH of 2.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 3
Incorrect
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Rapid Eye Movement (REM) sleep is typically associated with:
Your Answer: Somnambulism
Correct Answer: Penile erections
Explanation:Normal sleep comprises of alternate cycles between slow-wave sleep (non-REM sleep) and REM sleep. REM sleep is characterized by increased metabolic brain activity and EEG desynchronization. Somnambulism (sleepwalking), enuresis (bedwetting) and night terrors all occur during slow-wave sleep or during arousal from slow-wave sleep. In comparison, REM sleep is characterized by hypotonia of major muscle groups (excluding ocular muscles), dreams, nightmares and penile erection.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 4
Incorrect
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Some substances, such as Chromium-51 and Technetium-99, are freely filtered but not secreted or absorbed by the kidney. In these cases, their clearance rate is equal to:
Your Answer: Total volume of distribution
Correct Answer: Glomerular filtration rate
Explanation:If a substance passes through the glomerular membrane with perfect ease, the glomerular filtrate contains virtually the same concentration of the substance as does the plasma and if the substance is neither secreted nor reabsorbed by the tubules, all of the filtered substance continues on into the urine. Glomerular filtration rate (GFR) describes the flow rate of filtered fluid through the kidney.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 5
Incorrect
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Increased resistance to flow of blood in cerebral vessels is most likely seen in:
Your Answer: Epileptic seizure
Correct Answer: Elevation in systemic arterial pressure from 100 to 130 mmHg
Explanation:Constant cerebral blood flow is maintained by autoregulation in the brain, which causes an increase in local vascular resistance to offset an increase in blood pressure. There will be an increase in cerebral blood flow (and decrease in resistance to cerebral blood flow) with a decrease in arterial oxygen or an increase in arterial CO2. Similarly, a decrease in viscosity will also increase the blood flow. Due to increased brain metabolism and activity during a seizure, there will also be an increase in the cerebral blood flow.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 6
Incorrect
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Mechanical distortion, and not K+ channels are responsible for distortion of which of the following structures?
Your Answer: Rods and cones
Correct Answer: Pacinian corpuscle
Explanation:Pacinian corpuscles are a type of mechanoreceptor, sensitive to deep pressure, touch and high-frequency vibration. The Pacinian corpuscles are ovoid and about 1 mm long. In the centre of the corpuscle is the inner bulb, which is a fluid-filled cavity with a single afferent unmyelinated nerve ending. Any deformation in the corpuscle causes the generation of action potentials by opening of pressure-sensitive sodium ion channels in the axon membrane. This allows influx of sodium ions, creating a receptor potential (independent of potassium channels).
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This question is part of the following fields:
- Neurology
- Physiology
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Question 7
Correct
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Which is the site of action of the drug omeprazole?
Your Answer: H+/K+ ATPase
Explanation:H+/K+-ATPase or ‘proton pump’ located in the canalicular membrane plays a major role in acid secretion. The ATPase here is magnesium-dependent. Omeprazole is a proton pump inhibitor and blocks H+/K+- ATPase.
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This question is part of the following fields:
- Gastroenterology
- Physiology
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Question 8
Incorrect
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A 54-year-old woman with amyotrophic lateral sclerosis is diagnosed with respiratory acidosis. The patient’s renal excretion of potassium would be expected to:
Your Answer: Rise, since acid and potassium excretion are coupled
Correct Answer: Fall, since tubular secretion of potassium is inversely coupled to acid secretion
Explanation:Respiratory acidosis is a medical emergency in which decreased ventilation (hypoventilation) increases the concentration of carbon dioxide in the blood and decreases the blood’s pH (a condition generally called acidosis). Secretion of acid and potassium by the renal tubule are inversely related. So, increased excretion of H+ during renal compensation for respiratory acidosis will result in decreased secretion (or increased retention) of potassium ions, with the result that the body’s potassium store rises. An increase in K+ excretion would be associated with renal compensation for respiratory alkalosis. The filtered load of K+depends only on K+ plasma concentration and glomerular filtration rate, not on plasma pH.
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This question is part of the following fields:
- Physiology
- Renal
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Question 9
Incorrect
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A recognised side-effect of prefrontal leukotomy is:
Your Answer: Receptive aphasia
Correct Answer: Confusion
Explanation:Used previously as a treatment for psychiatric disorders, prefrontal leucotomy severs the connection between the prefrontal cortical association area and the thalamus. This leads to functional isolation of the prefrontal and orbitofrontal association cortex. Thus, along with the desired reduction in anger and frustration, undesirable side effects included changes in mood and affect, as well as confusion.
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This question is part of the following fields:
- Neurology
- Physiology
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Question 10
Incorrect
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Arterial blood gas analysis of a man admitted with acute exacerbation of chronic obstructive pulmonary disease (COPD) showed the following: pH = 7.28, p(CO2) = 65.5 mmHg, p(O2)= 60 mmHg and standard bicarbonate = 30.5 mmol/l. This patient had:
Your Answer:
Correct Answer: Respiratory acidosis
Explanation:Acidosis with high p(CO2) and normal standard bicarbonate indicates respiratory acidosis, commonly seen in acute worsening of COPD patients. Respiratory acidosis occurs due to alveolar hypoventilation which leads to increased arterial carbon dioxide concentration (p(CO2)). This in turn decreases the HCO3 –/p(CO2) and decreases pH. In acute respiratory acidosis, the p(CO2) is raised above the upper limit of normal (over 45 mm Hg) with a low pH. However, in chronic cases, the raised p(CO2) is accompanied with a normal or near-normal pH due to renal compensation and an increased serum bicarbonate (HCO3 – > 30 mmHg).
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
