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  • Question 1 - Which of the following will show decreased hearing when tested by air conduction...

    Incorrect

    • Which of the following will show decreased hearing when tested by air conduction but normal hearing when tested by bone conduction?

      Your Answer: Destruction of the cochlea

      Correct Answer: Fibrosis causing fixation of the ossicles

      Explanation:

      As the cochlea is embedded into bone, the vibrations from the bone are transmitted directly to the fluid in the cochlea. Hence, any damage to the ossicles or tympanic membrane will not show an abnormal result on bone conduction test.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      1188
      Seconds

  • Question 2 - Which organ is responsible for the secretion of enzymes that aid in digestion...

    Incorrect

    • Which organ is responsible for the secretion of enzymes that aid in digestion of complex starches?

      Your Answer:

      Correct Answer: Pancreas

      Explanation:

      α-amylase is secreted by the pancreas, which is responsible for hydrolysis of starch, glycogen and other carbohydrates into simpler compounds.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 3 - A patient presents with loss of pain and temperature sensation in the left...

    Incorrect

    • A patient presents with loss of pain and temperature sensation in the left leg. He is likely to have a lesion involving:

      Your Answer:

      Correct Answer: Right lateral spinothalamic tract

      Explanation:

      The spinothalamic tract is a sensory pathway originating in the spinal cord that transmits information to the thalamus. There are two main parts of the spinothalamic tract: the lateral spinothalamic tract transmits pain and temperature and the anterior spinothalamic tract transmits touch (crude touch). The decussation of this pathway occurs at the level of the spinal cord. Hence, a unilateral lesion of the lateral spinothalamic tract causes contralateral loss of pain and temperature.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 4 - Regarding the coagulation cascade, Factor VII: ...

    Incorrect

    • Regarding the coagulation cascade, Factor VII:

      Your Answer:

      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.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 5 - A TRUE statement regarding abolition of the cephalic phase of pancreatic secretion is...

    Incorrect

    • A TRUE statement regarding abolition of the cephalic phase of pancreatic secretion is that it:

      Your Answer:

      Correct Answer: Will result after vagotomy

      Explanation:

      Recognition and integration of the sight, smell and taste of food triggers the cephalic phase of pancreatic secretion, causing an increase in pancreatic HCO3- and enzyme secretion. The degree of enzyme secretion in this phase is about 50% of the maximal response seen with exogenous CCK and secretin. The vagus nerve regulates the secretion through the cholinergic fibres innervating the acinar cells of the pancreas, and through peptidergic nerve fibres, which innervate ductal cells.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 6 - A lesion involving the lateral geniculate nucleus of the thalamus is likely to...

    Incorrect

    • A lesion involving the lateral geniculate nucleus of the thalamus is likely to affect:

      Your Answer:

      Correct Answer: Vision

      Explanation:

      The lateral geniculate nucleus (LGN) of the thalamus is the primary processor of visual information in the central nervous system. The LGN receives information directly from the retina and sends projections directly to the primary visual cortex. The LGN likely helps the visual system focus its attention on the most important information.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 7 - Which of the following enzymes is secreted by the small intestinal mucosa? ...

    Incorrect

    • Which of the following enzymes is secreted by the small intestinal mucosa?

      Your Answer:

      Correct Answer: Lactase

      Explanation:

      Lactase, an enzyme belonging to β-galactosidase family of enzymes, brings about the hydrolysis of the disaccharide lactose into galactose and glucose. In humans, it is present along the brush border membrane of the cells lining the small intestinal villi. Deficiency of lactase causes lactose intolerance.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 8 - Which portion of the renal tubule absorbs amino acids and glucose? ...

    Incorrect

    • Which portion of the renal tubule absorbs amino acids and glucose?

      Your Answer:

      Correct Answer: Proximal convoluted tubule

      Explanation:

      In relation to the morphology of the kidney as a whole, the convoluted segments of the proximal tubules are confined entirely to the renal cortex. Glucose, amino acids, inorganic phosphate and some other solutes are reabsorbed via secondary active transport in the proximal renal tubule through co-transport channels driven by the sodium gradient.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds

  • Question 9 - If your EEG shows waves with a frequency range of 8-12 Hz, the...

    Incorrect

    • If your EEG shows waves with a frequency range of 8-12 Hz, the waves most likely to be seen are:

      Your Answer:

      Correct Answer: Alpha

      Explanation:

      Electroencephalography (EEG) is the neurophysiological measurement of the electrical activity of the brain. It is done by placing electrodes on the scalp or subdurally. In reality, the electrical currents are not measured, but rather the voltage differences between different parts of the brain. Four major types of EEG activity are recognized, which are alpha, beta, delta and theta.

      Alpha waves, also known as Berger’s waves ranges in frequency from 8-12 Hz. Best detected with eyes closed, alpha waves are characteristic of a relaxed, alert state of consciousness. An alpha-like normal variant called mu is sometimes seen over the motor cortex (central scalp) and attenuates with movement or, rather, with the intention to move.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 10 - Which of the following has the highest content of triglycerides? ...

    Incorrect

    • Which of the following has the highest content of triglycerides?

      Your Answer:

      Correct Answer: Chylomicron

      Explanation:

      Created by the small intestinal cells, chylomicrons are large lipoprotein molecules which transport lipids to the liver, adipose, cardiac and skeletal tissue. Chylomicrons are mainly composed of triglycerides (,85%) along with some cholesterol and cholesteryl esters. Apo B-48 is the main apolipoprotein content.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 11 - A 7-year-old girl is given cephalexin to treat an infection and develops hives,...

    Incorrect

    • A 7-year-old girl is given cephalexin to treat an infection and develops hives, with localised facial oedema. Which of the following conditions will cause localised oedema?

      Your Answer:

      Correct Answer: Angio-oedema

      Explanation:

      Angio-oedema, is the rapid swelling of the skin, mucosa and submucosal tissues. The underlying mechanism typically involves histamine or bradykinin. The version related to histamine is to due an allergic reaction to agents such as insect bites, food, or medications. The version related to bradykinin may occur due to an inherited C1 esterase inhibitor deficiency, medications e.g. angiotensin converting enzyme inhibitors, or a lymphoproliferative disorder.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds

  • Question 12 - During pregnancy the uterus enlarges however after delivery it regresses to its original...

    Incorrect

    • During pregnancy the uterus enlarges however after delivery it regresses to its original size. Which of the following organelles is responsible for this regression?

      Your Answer:

      Correct Answer: Lysosomes

      Explanation:

      Lysosomes are formed by budding of the Golgi apparatus and contain enzymes which digest macromolecules. They are found in both plants and animals and are active in autophagic cell death, digestion after phagocytosis and for the cells own recycling process. They fuse with the molecules and release their content resulting in digestion.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 13 - A 25-year-old woman complains of generalised swelling and particularly puffiness around the eyes...

    Incorrect

    • A 25-year-old woman complains of generalised swelling and particularly puffiness around the eyes which is worst in the morning. Laboratory studies showed:

      Blood urea nitrogen (BUN) = 30 mg/dl

      Creatinine = 2. 8 mg/dl

      Albumin = 2. 0 mg/dl

      Alanine transaminase (ALT) = 25 U/l

      Bilirubin = 1 mg/dl

      Urine analysis shows 3+ albumin and no cells.

      Which of the following is the most likely diagnosis?

      Your Answer:

      Correct Answer: Nephrotic syndrome

      Explanation:

      Nephrotic syndrome is a disorder in which the glomeruli have been damaged, characterized by:

      – Proteinuria (>3.5 g per 1.73 m2 body surface area per day, or > 40 mg per square meter body surface area per hour in children)

      – Hypoalbuminemia (< 2,5 g/dl) – Hyperlipidaemia, and oedema (generalized anasarca).

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds

  • Question 14 - Extracellular body fluid as compared with intracellular body fluid: ...

    Incorrect

    • Extracellular body fluid as compared with intracellular body fluid:

      Your Answer:

      Correct Answer: Is relatively rich in glucose

      Explanation:

      The percentages of body water contained in various fluid compartments add up to total body water (TBW). This water makes up a significant fraction of the human body, both by weight and by volume. Ensuring the right amount of body water is part of fluid balance, an aspect of homeostasis. The extracellular fluid (ECF) includes all fluids outside the cells. This fluid can be divided into three fluid departments: interstitial (in the tissue spaces) fluid, blood plasma and lymph, and specialised compartments called transcellular fluid. The extracellular fluid surrounds all the cells in the body and is in equilibrium with the intracellular fluid. So, its composition must remain fairly constant even though substances are passing into and out of the cells. The interstitial fluid, though called a fluid, is in a reality a gel-like composition made up of: water, proteoglycan molecules and collagen. The extracellular fluid constitutes 40% of total body water, with intracellular fluid making up the remaining 60%. It is relatively rich in glucose.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      0
      Seconds

  • Question 15 - Basal Metabolic Rate (BMR) will most likely be reduced by which of the...

    Incorrect

    • Basal Metabolic Rate (BMR) will most likely be reduced by which of the following?

      Your Answer:

      Correct Answer: Decrease in body temperature

      Explanation:

      The basal metabolic rate (BMR) is defined as the rate of calorie consumption after an overnight fast, in the absence of any muscular activity, with the patient in a restful state. Various factors affect the BMR including weight, body surface area and age. The BMR is 30 kcal/m2 per hour at birth; at age 2, the rate is 57 kcal/m2 per hour; and at age 20, 41 kcal/m2 per hour. After this, the BMR decreases by 10% between 20-60 years of age. Women are known to have a 10% lower BMR than men (due to higher fat content). A one-degree change in body temperature leads to a 10% change in BMR in the same direction. However, shivering and increasing ambient temperature brings about a rise in BMR, and so does stress, physical activity, caffeine, theophylline and hyperthyroidism. Also, thermogenesis induced by diet results in increased metabolic rate and hence, BMR should be ideally measured after overnight fasting.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 16 - Diffusion is the movement of molecules from a region of high concentration to a...

    Incorrect

    • Diffusion is the movement of molecules from a region of high concentration to a region of low concentration. Which of these changes will decrease the rate of diffusion of a substance?

      Your Answer:

      Correct Answer: An increase in the molecular weight of the substance

      Explanation:

      Unless given IV, a drug must cross several semipermeable cell membranes before it reaches the systemic circulation. Drugs may cross cell membranes by diffusion, amongst other mechanisms. The rate of diffusion of a substance is proportional to the difference in the concentration of the diffusing substance between the two sides of the membrane, the temperature of the solution, the permeability of the membrane and, in the case of ions, the electrical potential difference between the two sides of the membrane.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      0
      Seconds

  • Question 17 - In the glomerulus of the kidney, the mesangium is a structure associated with the capillaries. It has extraglomerular mesangial...

    Incorrect

    • In the glomerulus of the kidney, the mesangium is a structure associated with the capillaries. It has extraglomerular mesangial cells that:

      Your Answer:

      Correct Answer: Form the juxtaglomerular apparatus in combination with the macula densa and juxtaglomerular cells

      Explanation:

      The mesangium is an inner layer of the glomerulus, within the basement membrane surrounding the glomerular capillaries. The mesangial cells are phagocytic and secrete the amorphous basement membrane-like material known as the mesangial matrix. They are typically separated from the lumen of the capillaries by endothelial cells. The other type of cells in the mesangium are the extraglomerular mesangial cells which form the juxtaglomerular apparatus in combination with two other types of cells: the macula densa of the distal convoluted tubule and juxtaglomerular cells of the afferent arteriole. This apparatus controls blood pressure through the renin–angiotensin–aldosterone system.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds

  • Question 18 - The mechanism of action of streptokinase involves: ...

    Incorrect

    • The mechanism of action of streptokinase involves:

      Your Answer:

      Correct Answer: Direct conversion of plasminogen to plasmin

      Explanation:

      Streptokinase is an enzyme that is produced by group A beta haemolytic streptococcus and is an effective and cost efficient method for the dissolution of a clot used in cases of MI and pulmonary embolism. It works by directly converting plasminogen to plasmin which breaks down the blood components in the clot and fibrin, dissolving the clot. Streptokinase is a bacterial product and thus the body will develop immunity against it.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 19 - A teenage Somalian boy presents with a complaint of an enlarged lower jaw....

    Incorrect

    • A teenage Somalian boy presents with a complaint of an enlarged lower jaw. His blood film shows blast cells and macrophages. Which virus is responsible for this?

      Your Answer:

      Correct Answer: Epstein–Barr virus

      Explanation:

      Burkitt’s lymphoma is a type of non-Hodgkin’s lymphoma. Histologically it is characterised by a starry sky appearance due to numerous neoplastic macrophages which are required to clear the rapidly dividing tumour cells/blast cells. Burkitt’s lymphoma commonly affects the jaw bone, forming a huge tumour mass. It is associated with translocation of c-myc gene and has three types: 1) endemic/African type, 2)sporadic and 3)immunodeficiency-associated. The first type is strongly associated with EBV.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 20 - A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance...

    Incorrect

    • A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance will be raised in the plasma of this patient?

      Your Answer:

      Correct Answer: Bilirubin

      Explanation:

      Bilirubin is a yellow pigment that is formed due to the break down of RBCs. Haemolysis results in haemoglobin that is broken down into a haem portion and globin which is converted into amino acids and used again. Haem is converted into unconjugated bilirubin in the macrophages and shunted to the liver. In the liver it is conjugated with glucuronic acid making it water soluble and thus excreted in the urine. Its normal levels are from 0.2-1 mg/dl. Increased bilirubin causes jaundice and yellowish discoloration of the skin.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 21 - Calculate the cardiac output in an adult male with the following parameters:

    Heart...

    Incorrect

    • Calculate the cardiac output in an adult male with the following parameters:

      Heart rate 70 beats/min

      Arterial [O2] 0.24 ml O2/min

      Venous [O2] 0.16 ml O2/mi

      Whole body O2 consumption 500 ml/min

      Pulmonary diastolic pressure 15 mmHg

      Pulmonary systolic pressure 25 mmHg

      Wedge pressure 5 mmHg.

      Your Answer:

      Correct Answer: 6.25 l/min

      Explanation:

      As per Fick’s principle, VO2 = (CO × CAO2) – (CO × CVO2) where VO2 = oxygen consumption, CO = cardiac output, CAO2 = oxygen concentration of arterial blood and CVO2 = oxygen concentration of venous blood. Thus, CO = VO2/CAO2– CVO2, CO = 500/0.24 – 0.16, CO = 500/0.8, CO = 6.25 l/min.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      0
      Seconds

  • Question 22 - An experiment was conducted in which the skeletal muscle protein (not smooth muscle)...

    Incorrect

    • An experiment was conducted in which the skeletal muscle protein (not smooth muscle) involved in contraction was selectively inhibited. Which protein was inhibited?

      Your Answer:

      Correct Answer: Troponin

      Explanation:

      The mechanism of contraction of smooth muscles is different from that of skeletal muscles in which the contractile protein is troponin whilst in smooth muscle contraction is a protein called calmodulin. Calmodulin reacts with calcium ions and stimulates the formation of myosin crossbridges.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 23 - After a severe asthma attack, a 26-year-old woman is left in a markedly...

    Incorrect

    • After a severe asthma attack, a 26-year-old woman is left in a markedly hypoxic state. In which of the following organs are the arterial beds most likely to be vasoconstricted due to the hypoxia?

      Your Answer:

      Correct Answer: Lungs

      Explanation:

      Hypoxic pulmonary vasoconstriction is a local response to hypoxia resulting primarily from constriction of small muscular pulmonary arteries in response to reduced alveolar oxygen tension. This unique response of pulmonary arterioles results in a local adjustment of perfusion to ventilation. This means that if a bronchiole is obstructed, the lack of oxygen causes contraction of the pulmonary vascular smooth muscle in the corresponding area, shunting blood away from the hypoxic region to better-ventilated regions. The purpose of hypoxic pulmonary vasoconstriction is to distribute blood flow regionally to increase the overall efficiency of gas exchange between air and blood.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      0
      Seconds

  • Question 24 - Causes of metabolic acidosis with a normal anion gap include: ...

    Incorrect

    • Causes of metabolic acidosis with a normal anion gap include:

      Your Answer:

      Correct Answer: Diarrhoea

      Explanation:

      Excess acid intake and excess bicarbonate loss as in diarrhoea, are causes of metabolic acidosis with a normal anion gap. The other conditions all result in an increased anion gap.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      0
      Seconds

  • Question 25 - The most likely cause of a low p(O2) in arterial blood is: ...

    Incorrect

    • The most likely cause of a low p(O2) in arterial blood is:

      Your Answer:

      Correct Answer: Hypoxic hypoxia

      Explanation:

      Hypoxia is when the whole body or a region is deprived of adequate oxygen supply. Different types of hypoxia include the following:

      – Hypoxic hypoxia, which occurs due to poor oxygen supply, as a result of low partial pressure of oxygen in arterial blood. This could be due to low partial pressure of atmospheric oxygen (e.g., at high altitude), sleep apnoea, poor ventilation because of chronic obstructive pulmonary disease or respiratory arrest, or shunts. The other types of hypoxia have a normal partial pressure of oxygen.

      – Anaemic hypoxia occurs due to low total oxygen content of the blood, with a normal arterial oxygen pressure.

      – Hyperaemic hypoxia occurs due to poor delivery of oxygen to target tissues, such as in carbon monoxide poisoning or methemoglobinemia.

      – Histotoxic hypoxia results due to inability of the cells to use the delivered oxygen due to disabled oxidative phosphorylation enzymes.

      – Ischaemic (or stagnant) hypoxia occurs due to local flow restriction of well-oxygenated blood, seen in cases like cerebral ischaemia, ischaemic heart disease and intrauterine hypoxia.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      0
      Seconds

  • Question 26 - A 50 year old man on warfarin therapy following insertion of a pacemaker...

    Incorrect

    • A 50 year old man on warfarin therapy following insertion of a pacemaker presented with epistaxis. Which of the following is true regarding blood coagulation?

      Your Answer:

      Correct Answer: Patients with haemophilia A usually have a normal bleeding time

      Explanation:

      A prolonged bleeding time is seen in platelet disorders like thrombocytopenia. Patients with haemophilia A or B have a prolonged PTT but not a prolonged bleeding time.

      Ca2+ is necessary for coagulation.

      von Willebrand factor is an important part of the factor VIII complex and promotes platelet adhesion and aggregation.

      DIC results in depleted coagulation factors and accumulation of fibrin.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 27 - What is the result of maltase deficiency in the brush border of the...

    Incorrect

    • What is the result of maltase deficiency in the brush border of the small intestine?

      Your Answer:

      Correct Answer: Results in increased passage of maltose in stool

      Explanation:

      Maltase is an enzyme produced from the surface cells of the villi, lining the small intestine and aids in hydrolysing the disaccharide maltose, which splits into two molecules of α-glucose. It is done by breaking the glycosidic bond between the ‘first’ carbon of one glucose and the ‘fourth’ carbon of the other (a 1–4 bond). Hence, a deficiency of enzyme maltase will result in the increased passage of maltose in the stool.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 28 - Which of the following brings about a reduction in gastric blood flow? ...

    Incorrect

    • Which of the following brings about a reduction in gastric blood flow?

      Your Answer:

      Correct Answer: Vasopressin

      Explanation:

      Gastric blood flow is increased by vagal stimulation, gastrin, histamine and acetylcholine as they stimulate gastric section and the production of vasodilator metabolites. Acetylcholine and histamine also have a direct action on the gastric arterioles. Similarly, gastric blood flow is reduced by inhibitors of secretion – catecholamines, secretin and vasopressin.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      0
      Seconds

  • Question 29 - The gradual depolarization in-between action potentials in pacemaker tissue is a result of?...

    Incorrect

    • The gradual depolarization in-between action potentials in pacemaker tissue is a result of?

      Your Answer:

      Correct Answer: A combination of gradual inactivation outward IK along with the presence of an inward ‘funny’ current (If) due to opening of channels permeable to both Na+ and K+ ions

      Explanation:

      One of the characteristic features of the pacemaker cell is the generation of a gradual diastolic depolarization also called the pacemaker potential. In phase 0, the upstroke of the action potential caused by an increase in the Ca2+ conductance, an influx of calcium occurs and a positive membrane potential is generated. The next is phase 3 which is repolarization caused by increased K+ conductance as a result of outwards K+ current. Phase 4 is a slow depolarization which accounts for the pacemaker activity, caused by increased conductance of Na+, inwards Na+ current called IF. it is turned on by repolarization.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 30 - In a cardiac cycle, what event does the closing of atrioventricular (AV) valves...

    Incorrect

    • In a cardiac cycle, what event does the closing of atrioventricular (AV) valves coincide with?

      Your Answer:

      Correct Answer: Second heart sound

      Explanation:

      The beginning of ventricular systole corresponds to the beginning of the QRS complex in the ECG. The beginning of the ventricular systole also corresponds to the closure of the atrioventricular valves, causing the first heart sound (S1). S2, the second heart sound is due to closure of the aortic and pulmonary valves at the end of ventricular systole.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      0
      Seconds

  • Question 31 - A patient with a long standing lower motor neuron lesion will have: ...

    Incorrect

    • A patient with a long standing lower motor neuron lesion will have:

      Your Answer:

      Correct Answer: Muscle wasting

      Explanation:

      Lower motor neurons (LMNs) connect the brainstem and spinal cord to muscle fibres. Damage to lower motor neurons is indicated by abnormal electromyographic potentials, fasciculations, paralysis, weakening and wasting of skeletal muscles.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 32 - When one is silently counting, what part of his brain will show increased...

    Incorrect

    • When one is silently counting, what part of his brain will show increased regional cerebral blood flow (rCBF)?

      Your Answer:

      Correct Answer: Supplementary motor area

      Explanation:

      Regional cerebral blood flow (rCBF) increases in the superior speech cortex (supplementary motor area) during periods of silent counting, whereas speaking aloud will do so in the motor cortex and medial temporal lobe, along with the superior speech cortex.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 33 - A 30 year old man suffered severe blood loss, approx. 20-30% of his...

    Incorrect

    • A 30 year old man suffered severe blood loss, approx. 20-30% of his blood volume. What changes are most likely seen in the pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP) respectively following this decrease in cardiac output?

      Your Answer:

      Correct Answer: Increase Decrease

      Explanation:

      Hypovolemia will result in the activation of the sympathetic adrenal discharge resulting is a decrease pulmonary artery pressure and an elevated pulmonary vascular resistance.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      0
      Seconds

  • Question 34 - Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after...

    Incorrect

    • Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after a streptococcal infection?

      Your Answer:

      Correct Answer: Acute nephritic syndrome

      Explanation:

      Nephritic syndrome (or acute nephritic syndrome) is a syndrome comprising of signs of nephritis. Children between 2 and 12 are most commonly affected, but it may occur at any age. Predisposing factors/causes include:

      Infections with group A streptococcal bacteria (acute post-streptococcal glomerulonephritis).

      Primary renal diseases: immunoglobulin A nephropathy, membranoproliferative glomerulonephritis, idiopathic rapidly progressive crescentic glomerulonephritis.

      Secondary renal diseases: subacute bacterial endocarditis, infected ventriculo–peritoneal shunt, glomerulonephritis with visceral abscess, glomerulonephritis with bacterial, viral or parasitic infections.

      Multisystem diseases.

      By contrast, nephrotic syndrome is characterized by only proteins moving into the urine.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds

  • Question 35 - Destruction of the ventromedial nucleus of the hypothalamus will result in: ...

    Incorrect

    • Destruction of the ventromedial nucleus of the hypothalamus will result in:

      Your Answer:

      Correct Answer: Loss of satiety

      Explanation:

      The ventromedial nucleus of the hypothalamus is divided into an anterior and a superior part. The anterior part controls the female sexual drive, whereas the superior part is responsible for satiety. Destruction of the superior part of the nucleus will result in overeating, as no signal tells the body that it is satisfied.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      0
      Seconds

  • Question 36 - Decreased velocity of impulse conduction through the atrioventricular node (AV node) in the...

    Incorrect

    • Decreased velocity of impulse conduction through the atrioventricular node (AV node) in the heart will lead to:

      Your Answer:

      Correct Answer: Increased PR interval

      Explanation:

      AV node damage may lead to an increase in the PR interval to as high as 0.25 – 0.40 s (normal = 0.12 – 0.20 s). In the case of severe impairment, there might be a complete failure of passage of impulses leading to complete block. In this case, the atria and ventricles will beat independently of each other.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      0
      Seconds

  • Question 37 - Which of the following can lead to haemolytic anaemia? ...

    Incorrect

    • Which of the following can lead to haemolytic anaemia?

      Your Answer:

      Correct Answer: Presence of haemoglobin S

      Explanation:

      Haemoglobin S is an abnormal type of haemoglobin seen in sickle cell anaemia. This allows for the haemoglobin to crystalize within the RBC upon exposure to low partial pressures of oxygen. This results in rupture of the RBCs as they pass through microcirculation, especially in the spleen. This can cause blockage of the vessel down stream and ischaemic death of tissues, accompanied by severe pain.

    • This question is part of the following fields:

      • General
      • Physiology
      0
      Seconds

  • Question 38 - Which of the following is a true statement regarding secretion of gastric acid?...

    Incorrect

    • Which of the following is a true statement regarding secretion of gastric acid?

      Your Answer:

      Correct Answer: Acetylcholine increases gastric acid secretion

      Explanation:

      Gastric acid secretion is increased by acetylcholine, histamine and gastrin, with the help of cAMP as a secondary messenger. They increase H+ and Cl- secretion by increasing the number of H+/K+ ATPase molecules and Cl- channels. In contrast, gastric acid secretion is decreased by somatostatin, epidermal growth factor and prostaglandins.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
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  • Question 39 - Which of the following is true about a patient who has undergone total...

    Incorrect

    • Which of the following is true about a patient who has undergone total colectomy and ileostomy?

      Your Answer:

      Correct Answer: Following total colectomy and ileostomy, the volume and water content of ileal discharge decreases over time

      Explanation:

      After a patient has undergone total colectomy and ileostomy, the volume of ileal discharge, along with its water content gradually decreases over time. Post surgery, most patients can live a normal life. Iron and vitamin B12 absorption do not take place in the colon and hence are not affected significantly by a colectomy.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
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  • Question 40 - Renin is secreted by pericytes in the vicinity of the afferent arterioles of the...

    Incorrect

    • Renin is secreted by pericytes in the vicinity of the afferent arterioles of the kidney from the juxtaglomerular cells. Plasma renin levels are decreased in patients with:

      Your Answer:

      Correct Answer: Primary aldosteronism

      Explanation:

      Primary aldosteronism, also known as primary hyperaldosteronism or Conn’s syndrome, is excess production of the hormone aldosterone by the adrenal glands resulting in low renin levels. Most patients with primary aldosteronism (Conn’s syndrome) have an adrenal adenoma. The increased plasma aldosterone concentration leads to increased renal Na+ reabsorption, which results in plasma volume expansion. The increase in plasma volume suppresses renin release from the juxtaglomerular apparatus and these patients usually have low plasma renin levels. Salt restriction and upright posture decrease renal perfusion pressure and therefore increases renin release from the juxtaglomerular apparatus. Secondary aldosteronism is due to elevated renin levels and may be caused by heart failure or renal artery stenosis.

    • This question is part of the following fields:

      • Physiology
      • Renal
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  • Question 41 - Post-total gastrectomy, there will be a decreased production of which of the following...

    Incorrect

    • Post-total gastrectomy, there will be a decreased production of which of the following enzymes?

      Your Answer:

      Correct 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.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
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  • Question 42 - Which of the following substances will enhance the activity of antithrombin III? ...

    Incorrect

    • Which of the following substances will enhance the activity of antithrombin III?

      Your Answer:

      Correct Answer: Heparin

      Explanation:

      Antithrombin III is a glycoprotein that inactivates multiple enzymes involved in the coagulation system. It inactivates factor X, factor IX, factor II, factor VII, factor XI and factor XII. Its activity is greatly increased by the action of heparin.

    • This question is part of the following fields:

      • General
      • Physiology
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  • Question 43 - In which of the following conditions will the oxygen-haemoglobin dissociation curve shift to...

    Incorrect

    • In which of the following conditions will the oxygen-haemoglobin dissociation curve shift to the right?

      Your Answer:

      Correct Answer: Exercise

      Explanation:

      The oxygen-haemoglobin dissociation curve plots saturated haemoglobin against the oxygen tension and is usually a sigmoid plot. Each molecule of haemoglobin can bind to four molecules of oxygen reversibly. Factors that can influence the binding include: pH, concentration of 2,3-diphosphoglycerate (2,3-DPG), temperature, type of haemoglobin molecules, and presence of toxins, especially carbon monoxide. Shape of the curve is due to interaction of bound oxygen molecules with the incoming molecules. The binding of first molecule is difficult, with easier binding of the second and third molecule and increase in difficulty with the fourth molecule – partly as a result of crowding and partly as a natural tendency of oxygen to dissociate.

      Left shift of curve indicates haemoglobin’s increased affinity for oxygen (seen at lungs). Right shift indicates decreased affinity and is seen with an increase in body temperature, hydrogen ions, 2,3-diphosphoglycerate (DPG), carbon dioxide concentration and exercise. Under normal resting conditions in a healthy individual, the normal position of the curve is at a pH of 7.4. A shift in the position of the curve with a change in pH is called the Bohr effect. Left shift occurs in acute alkalosis, decrease in p(CO2), decrease in temperature and decrease in 2,3-DPG. The fetal haemoglobin curve is to the left of the adult haemoglobin to allow for oxygen diffusion across the placenta. The curve for myoglobin is even further to the left. Carbon monoxide has a much higher affinity for haemoglobin than oxygen does. Thus, carbon monoxide poisoning leads to hypoxia.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
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  • Question 44 - There are several mechanisms involved in the transport of sodium ions from blood...

    Incorrect

    • There are several mechanisms involved in the transport of sodium ions from blood to interstitial fluid of the muscle cells. Which of the following mechanisms best describes this phenomenon?

      Your Answer:

      Correct Answer: Diffusion through channels between endothelial cells

      Explanation:

      Capillaries are the smallest of the body’s blood vessels, measuring 5–10 μm and they help to enable the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between the blood and the tissues surrounding them. The walls of capillaries are composed of only a single layer of cells, the endothelium. Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells by allowing the flow of ions down their electrochemical gradient. An ion channel is an integral membrane protein or more typically an assembly of several proteins. The archetypal channel pore is just one or two atoms wide at its narrowest point. It conducts a specific ion such as sodium or potassium and conveys them through the membrane in single file.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
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  • Question 45 - In a hypertensive patient with secondary hyperaldosteronism, aldosterone is released mainly in response...

    Incorrect

    • In a hypertensive patient with secondary hyperaldosteronism, aldosterone is released mainly in response to:

      Your Answer:

      Correct Answer: Angiotensin II

      Explanation:

      Secondary hyperaldosteronism in hypertension is either due to primary renin overproduction by the kidneys or renin overproduction secondary to decreased renal blood flow. The main stimulus for aldosterone release are adrenocorticotrophic hormone (ACTH), angiotensin II and high plasma K+ levels. Low plasma Na+ might also stimulate the adrenal cortex. Fluid overload will reduce aldosterone secretion. Atrial natriuretic peptide is secreted under conditions of expanded extracellular volume and will not lead to aldosterone secretion.

    • This question is part of the following fields:

      • Endocrinology
      • Physiology
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  • Question 46 - Which of the following conditions causes an elevation of the pH in the...

    Incorrect

    • Which of the following conditions causes an elevation of the pH in the tissues with elevated arterial CO2 content?

      Your Answer:

      Correct Answer: Metabolic alkalosis

      Explanation:

      Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35-7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations. Normally, arterial pa(CO2) increases by 0.5–0.7 mmHg for every 1 mEq/l increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in pa(CO2) is not within this range, then a mixed acid–base disturbance occurs.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
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      Seconds

  • Question 47 - Which of the following is a potential cause of a positive D-dimer assay?...

    Incorrect

    • Which of the following is a potential cause of a positive D-dimer assay?

      Your Answer:

      Correct Answer: Deep venous thrombosis

      Explanation:

      A D-dimer test is performed to detect and diagnose thrombotic conditions and thrombosis. A negative result would rule out thrombosis and a positive result although not diagnostic, is highly suspicious of thrombotic conditions like a deep vein thrombosis, pulmonary embolism as well as DIC.

    • This question is part of the following fields:

      • General
      • Physiology
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  • Question 48 - A patient presents with loss of fine touch and sense of proprioception in...

    Incorrect

    • A patient presents with loss of fine touch and sense of proprioception in the lower part of the body (below T6). He is likely to have a lesion involving:

      Your Answer:

      Correct Answer: Gracile nucleus

      Explanation:

      The gracile nucleus is located in the medulla oblongata and is one of the dorsal column nuclei involved in the sensation of fine touch and proprioception. It contains second-order neurons of the dorsal column–medial lemniscus system, that receive inputs from sensory neurones of the dorsal root ganglia and send axons that synapse in the thalamus.

      The gracile nucleus and fasciculus carry epicritic, kinaesthetic and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). Similar information from the upper part of body (above T6, except for face and ear) is carried by the cuneate nucleus and fasciculus. The information from face and ear is carried by the primary sensory trigeminal nucleus.

    • This question is part of the following fields:

      • Neurology
      • Physiology
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  • Question 49 - The pleural cavity is the space between the two pulmonary pleurae which cover...

    Incorrect

    • The pleural cavity is the space between the two pulmonary pleurae which cover the lungs. What is the normal amount of pleural fluid?

      Your Answer:

      Correct Answer: 10 ml

      Explanation:

      Pleural fluid is a serous fluid produced by the serous membrane covering normal pleurae. Most fluid is produced by the parietal circulation (intercostal arteries) via bulk flow and reabsorbed by the lymphatic system. The total volume of fluid present in the intrapleural space is estimated to be only 2–10 ml. A small amount of protein is present in intrapleural fluid. Normally, the rate of reabsorption increases as a physiological response to accumulating fluid.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
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  • Question 50 - Which of the following can occur even in the absence of brainstem co-ordination?...

    Incorrect

    • Which of the following can occur even in the absence of brainstem co-ordination?

      Your Answer:

      Correct Answer: Gastric emptying

      Explanation:

      Although gastric emptying is under both neural and hormonal control, it does not require brainstem co-ordination. Increased motility of the orad stomach (decreased distensibility) or of the distal stomach (increased peristalsis), decreased pyloric tone, decreased duodenal motility or a combination of these, all increase the rate of gastric emptying. The major control mechanism for gastric emptying is through duodenal gastric feedback. The duodenum has receptors for the presence of acid, carbohydrate, fat and protein digestion products, osmolarity different from that of plasma, and distension. Activating these receptors decreases the rate of gastric emptying. Neural mechanisms involve both enteric and vagal pathways and a vagotomy impairs the gastric emptying regulation. CCK (cholecystokinin) slows gastric emptying at physiological levels of the hormone. Gastrin, secretin and glucose-1-phosphate also slow gastric emptying, but require higher doses.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
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