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  • Question 1 - Which of the following substances brings about a dilatation of the gastrointestinal resistance...

    Incorrect

    • Which of the following substances brings about a dilatation of the gastrointestinal resistance vessels?

      Your Answer: Vasopressin

      Correct Answer: Vasoactive intestinal peptide

      Explanation:

      Gastric vasoconstrictors include catecholamines, angiotensin II and vasopressin. Vasodilators include vasoactive intestinal peptide and the hormones; gastrin, cholecystokinin and glucagon.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      6
      Seconds
  • Question 2 - C5a (a complement component) is a potent? ...

    Incorrect

    • C5a (a complement component) is a potent?

      Your Answer: Opsonin

      Correct Answer: Anaphylotoxin

      Explanation:

      C5a is a strong chemoattractant as well as an anaphylotoxin and is involved in the recruitment of inflammatory cells such as neutrophils, eosinophils, monocytes, and T lymphocytes. It is also involved in activation of phagocytic cells, release of granule-based enzymes and generation of oxidants. All of which contribute to innate immune functions.

    • This question is part of the following fields:

      • General
      • Physiology
      10.1
      Seconds
  • Question 3 - In what form are fats primarily transported in the body? ...

    Incorrect

    • In what form are fats primarily transported in the body?

      Your Answer: Phospholipids

      Correct Answer: Free fatty acids

      Explanation:

      Fat is mainly transported in the body as free fatty acids. Once out of the adipose cell, the free fatty acids get ionized and combine with albumin.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      51.4
      Seconds
  • Question 4 - What is the reason for a deranged thrombin clotting time? ...

    Incorrect

    • What is the reason for a deranged thrombin clotting time?

      Your Answer: Warfarin therapy

      Correct Answer: Heparin therapy

      Explanation:

      Thrombic clotting time is also known as thrombin time. It is clinically performed to determine the therapeutic levels of heparin. After plasma is isolated from the blood, bovine thrombin is added to it and the time it takes from the addition to clot is recorded. The reference interval is usually <21s. deranged results are indicative of heparin therapy, hypofibrinogenemia, hyperfibrinogenaemia or lupus anticoagulant.

    • This question is part of the following fields:

      • General
      • Physiology
      22
      Seconds
  • Question 5 - Severe abdominal pain radiating to the back, along with increased serum amylase levels,...

    Incorrect

    • Severe abdominal pain radiating to the back, along with increased serum amylase levels, is seen in which of the following conditions?

      Your Answer: Hepatitis

      Correct Answer: Pancreatitis

      Explanation:

      The primary test for diagnosis and monitoring of pancreatitis is amylase. Increased plasma levels of amylase can be found in: salivary trauma (including anaesthetic intubation), mumps, pancreatitis and renal failure. However, a rise in the total amylase levels over 10 times the upper limit of normal (ULN) is suggestive of pancreatitis; 5–10 times the ULN may indicate ileus or duodenal disease or renal failure. Lower levels are commonly found in salivary gland disease.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      6
      Seconds
  • Question 6 - After having donated a unit of blood. The blood bank will prefer to...

    Incorrect

    • After having donated a unit of blood. The blood bank will prefer to use which of the following anticoagulants to store the blood?

      Your Answer: Heparin

      Correct Answer: Citrate

      Explanation:

      Calcium is necessary for coagulation to occur. Citrate being a chelator and combining with calcium ions to form un-ionised compound will prevent coagulation. Following transfusion the citrate is removed by the liver with in a few minutes. Oxalate also works on the same principle but it is toxic to the body.

    • This question is part of the following fields:

      • General
      • Physiology
      4.1
      Seconds
  • Question 7 - The majority of gallstones are mainly composed of: ...

    Incorrect

    • The majority of gallstones are mainly composed of:

      Your Answer: Calcium

      Correct Answer: Cholesterol

      Explanation:

      Bile salts are formed out of cholesterol in the liver cells. Occasionally, precipitation of cholesterol occurs resulting into cholesterol stones developing in the gall bladder.

      These cholesterol gallstones are the most common type and account for 80% of all gallstones. Another type, accounting for 20% gallstones is pigment stones which are composed of bilirubin and calcium salts. Occasionally, stones of mixed origin are also seen.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      23
      Seconds
  • Question 8 - Calculate the total peripheral resistance for a patient with a blood pressure of...

    Incorrect

    • Calculate the total peripheral resistance for a patient with a blood pressure of 130/70 mm HG and cardiac output of 5 litres / min?

      Your Answer: 30 mmHg × min/l

      Correct Answer: 18 mmHg × min/l

      Explanation:

      Total peripheral resistance = Mean arterial pressure/Cardiac output. And the mean arterial pressure = Diastolic pressure + 1/3 (Systolic pressure – Diastolic pressure), i.e., 70 + 1/3 (130-70) = 90 mmHg. Therefore, total peripheral resistance = 90 mmHg/5 l per min = 18 mmHg × min/l.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      28.8
      Seconds
  • Question 9 - With respect to far accommodation, which of the following is a TRUE statement?...

    Incorrect

    • With respect to far accommodation, which of the following is a TRUE statement?

      Your Answer: The focal length of the lens is short

      Correct Answer: The ciliary muscles are relaxed

      Explanation:

      Myopia or near-sightedness is a disease due to elongated eyeballs or too strong a lens. For far accommodation (focus of a distant object onto the retina), the lens needs to decrease its refractive power, or in other words, increase its focal length. This is done by relaxation of ciliary muscles which tightens the zonular fibres and flattening of the lens. Relaxation of the zonular fibres, rounding of the lens, shortening of the focal length and constriction of the pupil occurs during near accommodation.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      10.7
      Seconds
  • Question 10 - When does the heart rate decrease? ...

    Incorrect

    • When does the heart rate decrease?

      Your Answer: On inspiration

      Correct Answer: Pressure on the eyeball

      Explanation:

      Various vagotonic manoeuvres (e.g. Valsalva manoeuvre, carotid sinus massage, pressure on eyeballs, ice-water facial immersion, swallowing of ice-cold water) result in increased parasympathetic tone through the vagus nerve which results in a decrease in heart rate. These manoeuvres may be clinically useful in terminating supraventricular arrhythmias.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      14.1
      Seconds
  • Question 11 - A 50-year-old woman goes to the doctor complaining of myalgia, muscle cramps, and...

    Incorrect

    • A 50-year-old woman goes to the doctor complaining of myalgia, muscle cramps, and weakness; she is diagnosed with severe hypokalaemia. Which of the following is the most common cause of hypokalaemia?

      Your Answer: Acute respiratory acidosis

      Correct Answer: Prolonged vomiting

      Explanation:

      Potassium is one of the body’s major ions. Nearly 98% of the body’s potassium is intracellular. The ratio of intracellular to extracellular potassium is important in determining the cellular membrane potential. Small changes in the extracellular potassium level can have profound effects on the function of the cardiovascular and neuromuscular systems. Hypokalaemia may result from conditions as varied as renal or gastrointestinal (GI) losses, inadequate diet, transcellular shift (movement of potassium from serum into cells) and medications. The important causes of hypokalaemia are:

      Renal losses: renal tubular acidosis, hyperaldosteronism, magnesium depletion, leukaemia (mechanism uncertain).

      GI losses: vomiting or nasogastric suctioning, diarrhoea, enemas or laxative use, ileal loop.

      Medication effects: diuretics (most common cause), β-adrenergic agonists, steroids, theophylline, aminoglycosides.

      Transcellular shift: insulin, alkalosis.

      Severe hypokalaemia, with serum potassium concentrations of 2.5–3 meq/l, may cause muscle weakness, myalgia, tremor, muscle cramps and constipation.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      18.9
      Seconds
  • Question 12 - Which of the following has the highest content of triglycerides? ...

    Incorrect

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

      Your Answer: VLDL

      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
      30.5
      Seconds
  • Question 13 - 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: Chronic renal failure

      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
      12.8
      Seconds
  • Question 14 - The bronchial circulation is a part of the circulatory system that supplies nutrients and oxygen to the pulmonary...

    Incorrect

    • The bronchial circulation is a part of the circulatory system that supplies nutrients and oxygen to the pulmonary parenchyma. What percentage of cardiac output is received by bronchial circulation?

      Your Answer: 30%

      Correct Answer: 2%

      Explanation:

      The bronchial circulation is part of the systemic circulation and receives about 2% of the cardiac output from the left heart. Bronchial arteries arise from branches of the aorta, intercostal, subclavian or internal mammary arteries. The bronchial arteries supply the tracheobronchial tree with both nutrients and O2. It is complementary to the pulmonary circulation that brings deoxygenated blood to the lungs and carries oxygenated blood away from them in order to oxygenate the rest of the body.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      34.4
      Seconds
  • Question 15 - Which of the following is likely to induce secretion of glucagon? ...

    Incorrect

    • Which of the following is likely to induce secretion of glucagon?

      Your Answer: High serum concentration of glucose

      Correct Answer: Low serum concentration of glucose

      Explanation:

      The most potent stimulus for secretion of glucagon is hypoglycaemia whereas hyperglycaemia is a stimulus for insulin release. Glucagon secretion also occurs in response to high levels of amino acids. Somatostatin inhibits glucagon secretion. Parasympathetic stimulation increases pancreatic acinar secretion, but not of α-cells.

    • This question is part of the following fields:

      • Endocrinology
      • Physiology
      23.1
      Seconds
  • Question 16 - Which of the following substances is most likely to cause pulmonary vasodilatation? ...

    Incorrect

    • Which of the following substances is most likely to cause pulmonary vasodilatation?

      Your Answer: ADH

      Correct Answer: Nitric oxide

      Explanation:

      In the body, nitric oxide is synthesised from arginine and oxygen by various nitric oxide synthase (NOS) enzymes and by sequential reduction of inorganic nitrate. The endothelium of blood vessels uses nitric oxide to signal the surrounding smooth muscle to relax, so dilating the artery and increasing blood flow. Nitric oxide/oxygen blends are used in critical care to promote capillary and pulmonary dilation to treat primary pulmonary hypertension in neonatal patients post-meconium aspiration and related to birth defects.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      61.9
      Seconds
  • Question 17 - A 20-year old gentleman was brought to the emergency department with headache and...

    Incorrect

    • A 20-year old gentleman was brought to the emergency department with headache and nausea for 2 days. He also complained of intolerance to bright light and loud sounds. Lumbar puncture showed glucose < 45 mg/dl, protein > 5 mg/dl and neutrophil leucocytosis. The likely diagnosis is:

      Your Answer: Cerebral malaria

      Correct Answer: Meningitis

      Explanation:

      Diagnosis of meningitis can be carried out with examination of cerebrospinal fluid (CSF) with a lumbar puncture (LP). In a case of bacterial meningitis, the CSF analysis will show:

      – Opening pressure: > 180 mmH2O

      – White blood cell count: 10–10 000/μl with neutrophil predominance

      – Glucose: < 40 mg/dl – CSF glucose to serum glucose ratio: < 0.4 – Protein: > 4.5 mg/dl

      – Gram stain: positive in > 60%

      – Culture: positive in > 80%

      – Latex agglutination: may be positive in meningitis due to Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Escherichia coli and group B streptococci

      – Limulus, lysates: positive in Gram-negative meningitis

    • This question is part of the following fields:

      • Neurology
      • Physiology
      38.4
      Seconds
  • Question 18 - Gastric acid secretion is stimulated by which of the following? ...

    Incorrect

    • Gastric acid secretion is stimulated by which of the following?

      Your Answer: Cholecystokinin

      Correct Answer: Gastrin

      Explanation:

      Gastric acid secretion is stimulated by three factors:

      – Acetylcholine, from parasympathetic neurones of the vagus nerve that innervate parietal cells directly

      – Gastrin, produced by pyloric G-cells

      – Histamine, produced by mast cells.

      Gastric acid is inhibited by three factors:

      – Somatostatin

      – Secretin

      – Cholecystokinin

    • This question is part of the following fields:

      • Endocrine
      • Physiology
      94.6
      Seconds
  • Question 19 - A 65-year old patient with altered bowl movement experienced the worsening of...

    Correct

    • A 65-year old patient with altered bowl movement experienced the worsening of shortness of breath and exertional chest pains over the course of 8 weeks. Examination shows pallor and jugular venous distension. Furthermore, a test of the stool for occult blood is positive. Laboratory studies show:

      Haemoglobin 7.4 g/dl

      Mean corpuscular volume 70 fl Leukocyte count 5400/mm3

      Platelet count 580 000/mm3 Erythrocyte sedimentation 33 mm/h

      A blood smear shows hypochromic, microcytic RBCs with moderate poikilocytosis. Which of the following is the most likely diagnosis?

      Your Answer: Iron deficiency anaemia

      Explanation:

      Iron deficiency anaemia is the most common type of anaemia. It can occur due to deficiency of iron due to decreased intake or due to faulty absorption. An MCV less than 80 will indicated iron deficiency anaemia. On the smear the RBC will be microcytic hypochromic and will also show piokilocytosis. iron profiles tests are important to make a diagnosis. Clinically the patient will be pale and lethargic.

    • This question is part of the following fields:

      • General
      • Physiology
      17.7
      Seconds
  • Question 20 - Basal Metabolic Rate (BMR) will most likely be reduced by which of the...

    Correct

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

      Your 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
      21.7
      Seconds
  • Question 21 - Calculate the resistance of the artery if the pressure at one end is...

    Correct

    • Calculate the resistance of the artery if the pressure at one end is 60 mmHg, pressure at the other end is 20 mm Hg and the flow rate in the artery is 200 ml/min.

      Your Answer: 0.2

      Explanation:

      Flow in any vessel = Effective perfusion pressure divided by resistance, where effective perfusion pressure is the mean intraluminal pressure at the arterial end minus the mean pressure at the venous end. Thus, in the given problem, resistance = (60 − 20)/200 = 0.2 mmHg/ml per min.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      35.4
      Seconds
  • Question 22 - Calculate the cardiac output of a patient with the following measurements: oxygen uptake...

    Incorrect

    • Calculate the cardiac output of a patient with the following measurements: oxygen uptake 200 ml/min, oxygen concentration in the peripheral vein 7 vol%, oxygen concentration in the pulmonary artery 10 vol% and oxygen concentration in the aorta 15 vol%.

      Your Answer: 3500 ml/min

      Correct Answer: 4000 ml/min

      Explanation:

      The Fick’s principle states that the uptake of a substance by an organ equals the arteriovenous difference of the substance multiplied by the blood flowing through the organ. We can thus calculate the pulmonary blood flow with pulmonary arterial (i.e., mixed venous) oxygen content, aortic oxygen content and oxygen uptake. The pulmonary blood flow, systemic blood flow and cardiac output can be considered the same assuming there are no intracardiac shunts. Thus, we can calculate the cardiac output. Cardiac output = oxygen uptake/(aortic − mixed venous oxygen content) = 200 ml/min/(15 ml O2/100 ml − 10 ml O2/100 ml) = 200 ml/min/(5 ml O2/100 ml) = 200 ml/min/0.05 = 4000 ml/min.

      It is crucial to remember to use pulmonary arterial oxygen content and not peripheral vein oxygen content, when calculating the cardiac output by Fick’s method.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      7.4
      Seconds
  • Question 23 - Production of pain is most likely associated with: ...

    Correct

    • Production of pain is most likely associated with:

      Your Answer: Substance P

      Explanation:

      Substance P is a short-chain polypeptide that functions as a neurotransmitter and as a neuromodulator, and is thus, a neuropeptide. It has been linked with pain regulation, mood disorders, stress, reinforcement, neurogenesis, respiratory rhythm, neurotoxicity, nausea and emesis. It is also a potent vasodilator as it brings about release of nitric oxide from the endothelium. Its release can also cause hypotension.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      67.7
      Seconds
  • Question 24 - Selective destruction of which of the following cells will affect antibody synthesis? ...

    Incorrect

    • Selective destruction of which of the following cells will affect antibody synthesis?

      Your Answer: Reticulocytes

      Correct Answer: Plasma cells

      Explanation:

      Plasma cell are memory cells. After the antigen Is engulfed by the B cells it is presented to the CD4+ helper cells via the MCH II receptor and this leads to their activation which in turn stimulates the B cells to form antibodies against that specific antigen. Some B cells differentiate into plasma cells also called memory cells that get activated after subsequent infection.

    • This question is part of the following fields:

      • General
      • Physiology
      22.9
      Seconds
  • Question 25 - Which of the following is a true statement regarding the pupil? ...

    Incorrect

    • Which of the following is a true statement regarding the pupil?

      Your Answer: General increase in sympathetic tone during emotional excitement results in pupil constriction

      Correct Answer: Phentolamine causes pupil constriction

      Explanation:

      A balance between the sympathetic tone to the radial fibres of the iris and parasympathetic tone to the pupillary sphincter muscle determines the pupil size. Phentolamine (α-adrenergic receptor blocker) causes pupillary constriction. Dilatation of the pupil occurs with increased sympathetic activity, decreased parasympathetic activity during darkness or block of muscarinic receptors by atropine.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      43.2
      Seconds
  • Question 26 - A 26-year-old female patient had the following blood report: RBC count = 4....

    Incorrect

    • A 26-year-old female patient had the following blood report: RBC count = 4. 0 × 106/μl, haematocrit = 27% and haemoglobin = 11 g/dl, mean corpuscular volume (MCV) = 80–100 fl, mean corpuscular haemoglobin concentration (MCHC) = 31–37 g/dl. Which of the following is correct regarding this patient’s erythrocytes:

      Your Answer: Normal MCHC

      Correct Answer: Normal MCV

      Explanation:

      MCV is the mean corpuscular volume and it is calculated from the haematocrit and the RBC count. It is normally 90 fl. Mean corpuscular haemoglobin concentration (MCHC) [g/dl] = haemoglobin [g/dl]/haematocrit = 11/0.27 = 41 g/dl and is higher than normal range (32 to 36 g/dL).

    • This question is part of the following fields:

      • General
      • Physiology
      17.2
      Seconds
  • Question 27 - The anatomical dead space in a patient with low oxygen saturation, is 125...

    Correct

    • The anatomical dead space in a patient with low oxygen saturation, is 125 ml, with a tidal volume of 500 ml and pa(CO2) of 40 mm Hg. The dead space was determined by Fowler's method. If we assume that the patient's lungs are healthy, what will his mixed expired CO2 tension [pE(CO2)] be?

      Your Answer: 30 mmHg

      Explanation:

      According to Bohr’s equation, VD/VT = (pA(CO2) − pE(CO2))/pA(CO2), where pE(CO2) is mixed expired CO2 and pA(CO2) is alveolar CO2pressure. Normally, the pa(CO2) is virtually identical to pA(CO2). Thus, VD/VT = (pa(CO2)) − pE(CO2)/pa(CO2). By Fowler’s method, VD/VT= 0.25. In the given problem, (pa(CO2) − pE(CO2)/pa(CO2) = (40 − pE(CO2)/40 = 0.25. Thus, pE(CO2) = 30 mmHg. If there is a great perfusion/ventilation inequality, pE(CO2) could be significantly lower than 30 mm Hg, and the patient’s physiological dead space would exceed the anatomical dead space.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      22.2
      Seconds
  • Question 28 - If the blood flow is constant, oxygen extraction by tissues will show the...

    Incorrect

    • If the blood flow is constant, oxygen extraction by tissues will show the greatest decrease due to which of the following interventions?

      Your Answer: Fever

      Correct Answer: Tissue cooling

      Explanation:

      With a constant blood flow to a given tissue bed, there will be an increase in oxygen extraction by the tissue with the following; an increase in tissue metabolism and oxygen requirements: warming (or fever), exercise, catecholamines and thyroxine. With cooling, the demand for oxygen decreases, leading to decreased oxygen extraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      24.3
      Seconds
  • Question 29 - What is the normal duration of PR interval on an electrocardiogram of a...

    Correct

    • What is the normal duration of PR interval on an electrocardiogram of a healthy individual?

      Your Answer: 0.12–0.20 s

      Explanation:

      PR interval extends from the beginning of the P-wave until the beginning of the QRS complex. The normal duration of the PR interval is 0.12-0.20 s. It can be prolonged in first degree heart block, and reduced in Wolff-Parkinson-White syndrome.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      35.5
      Seconds
  • Question 30 - A 50 year old man was admitted to the surgical ICU following a...

    Incorrect

    • A 50 year old man was admitted to the surgical ICU following a hemicolectomy for carcinoma of the caecum. A full blood count revealed: haematocrit = 30%, erythrocytes = 4 × 106/μ, haemoglobin level = 8 g/dl. To determine the likely cause of his anaemia, red blood cell indices were calculated. Which RBC indices are correct?

      Your Answer: MCV = haemoglobin concentration/haematocrit

      Correct Answer: MCHC = haemoglobin concentration/haematocrit

      Explanation:

      Mean corpuscular haemoglobin concentration (MCHC) is calculated simply by dividing the haemoglobin concentration (8 g/dl) by the haematocrit (0.3). The normal range is 31–36 g/dl. This patient has a hypochromic anaemia (MCHC = 8/0.3 = 26.7 g/dl). Dividing the haemoglobin concentration × 10 by erythrocyte number yields mean corpuscular haemoglobin (MCH). Normal range is 25.4–34.6 pg/cell and this patient has a significantly reduced cellular haemoglobin content (MCH = 8 × 10/4 = 20 pg/cell). Mean corpuscular volume (MCV) is calculated by dividing haematocrit × 1000 by erythrocyte number (4 × 106/μl). Normal range is 80–100 fl and this patient has a microcytic anaemia (MCV = 0.3 × 1000/4 = 75 fl). Microcytic, hypochromic anaemia is characteristic for iron-deficiency.

    • This question is part of the following fields:

      • General
      • Physiology
      54.5
      Seconds
  • Question 31 - A 79-year-old has been bedridden for 2 months after suffering from a stroke....

    Incorrect

    • A 79-year-old has been bedridden for 2 months after suffering from a stroke. She suddenly developed shortness of breath and chest pain, and was diagnosed with a pulmonary embolism. Which of the following is most likely to increase in this case?

      Your Answer: Lung volume

      Correct Answer: Ventilation/perfusion ratio

      Explanation:

      Pulmonary embolism (PE) is a blockage of an artery in the lungs by an embolus that has travelled from elsewhere in the body through the bloodstream. The change in cardiopulmonary function is proportional to the extent of the obstruction, which varies with the size and number of emboli obstructing the pulmonary arteries. The resulting physiological changes may include pulmonary hypertension with right ventricular failure and shock, dyspnoea with tachypnoea and hyperventilation, arterial hypoxaemia and pulmonary infarction. Consequent alveolar hyperventilation is manifested by a lowered pa(CO2). After occlusion of the pulmonary artery, areas of the lung are ventilated but not perfused, resulting in wasted ventilation with an increased ventilation/perfusion ratio – the physiological hallmark of PE – contributing to a further hyperventilatory state. The risk of blood clots is increased by cancer, prolonged bed rest, smoking, stroke, certain genetic conditions, oestrogen-based medication, pregnancy, obesity, and post surgery.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      12.5
      Seconds
  • Question 32 - A patient admitted for esophagectomy showed low levels of the lightest plasma protein...

    Correct

    • A patient admitted for esophagectomy showed low levels of the lightest plasma protein in terms of weight. Which of the following is the lightest plasma protein:

      Your Answer: Albumin

      Explanation:

      Albumin is the most abundant and the lightest of all the plasma proteins. It maintains osmotic pressure, transports unconjugated bilirubin, thyroid hormones, fatty acids, drugs and acts as a buffer for pH.

    • This question is part of the following fields:

      • General
      • Physiology
      7.3
      Seconds
  • Question 33 - The primary area involved in the pathology of Parkinson's disease is: ...

    Incorrect

    • The primary area involved in the pathology of Parkinson's disease is:

      Your Answer: Basal ganglia

      Correct Answer: Substantia nigra

      Explanation:

      Parkinson’s disease is a degenerative, movement disorder of the central nervous system, and is typically characterized by muscle rigidity, tremor and bradykinesia (in extreme cases, akinesia). Secondary symptoms include high-level cognitive dysfunction and subtle language problems.

      Parkinson’s disease is also called ‘primary Parkinsonism’ or ‘idiopathic Parkinson’s disease and is the most common cause of Parkinsonism, a group of similar symptoms. The disorder is caused due to loss of pigmented dopaminergic cells in the pars compacta region of the substantia nigra.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      45.7
      Seconds
  • Question 34 - During strenuous exercise, what else occurs besides tachycardia? ...

    Incorrect

    • During strenuous exercise, what else occurs besides tachycardia?

      Your Answer: Increased renal blood flow

      Correct Answer: Increased stroke volume

      Explanation:

      During strenuous exercise there is an increase in:

      – Heart rate, stroke volume and therefore cardiac output. (CO = HR x SV)

      – Respiratory rate (hyperventilation) which will lead to a reduction in Paco2.

      – Oxygen demand of skeletal muscle, therefore leading to a reduction in mixed venous blood oxygen concentration.

      Renal blood flow is autoregulated, so renal blood flow is preserved and will tend to remain the same. Mean arterial blood pressure is a function of cardiac output and total peripheral resistance and will increase with exercise, mainly as a result of the increase in cardiac output that occurs.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.1
      Seconds
  • Question 35 - A 30 year old female suffered from mismatched transfusion induced haemolysis. Which substance...

    Correct

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

      Your 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
      4.5
      Seconds
  • Question 36 - Which of the following can lead to haemolytic anaemia? ...

    Incorrect

    • Which of the following can lead to haemolytic anaemia?

      Your Answer: Living at high altitude

      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
      46.7
      Seconds
  • Question 37 - Extracellular body fluid as compared with intracellular body fluid: ...

    Correct

    • Extracellular body fluid as compared with intracellular body fluid:

      Your 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
      10.5
      Seconds
  • Question 38 - What is the pH of freshly formed saliva at ultimate stimulation? ...

    Incorrect

    • What is the pH of freshly formed saliva at ultimate stimulation?

      Your Answer: 2. 0

      Correct Answer: 8

      Explanation:

      Saliva has four major components: mucus (lubricant), α-amylase (enzyme that initiates digestion of starch), lingual lipase (enzyme that begins fat digestion), and a slightly alkaline electrolyte solution for moistening food. As the secretion rate of saliva increases, its osmolality increases. Moreover, the pH changes from slightly acidic (at rest) to basic (pH 8) at ultimate stimulation. This occurs due to increase of HCO3-. Amylase and mucus also increase in concentration after stimulation.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      21.4
      Seconds
  • Question 39 - Diffusion is the movement of molecules from a region of high concentration to a...

    Correct

    • 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: 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
      42.3
      Seconds
  • Question 40 - A 77-year-old woman's renal function is tested. The following results were obtained during...

    Incorrect

    • A 77-year-old woman's renal function is tested. The following results were obtained during a 24-h period:

      Urine flow rate: 2. 0 ml/min

      Urine inulin: 0.5 mg/ml

      Plasma inulin: 0.02 mg/ml

      Urine urea: 220 mmol/l

      Plasma urea: 5 mmol/l.

      What is the urea clearance?

      Your Answer: 320 ml/min

      Correct Answer: 88 ml/min

      Explanation:

      Urea is reabsorbed in the inner medullary collecting ducts of the nephrons. The clearance (C) of any substance can be calculated as follows: C = (U × V)/P, where U and P are the urine and plasma concentrations of the substance, respectively and V is the urine flow rate. So, glomerular filtration rate = (0.220 × 2. 0)/0.005 = 88 ml/min.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      16.2
      Seconds
  • Question 41 - A 25 year old man presented with a history of headache and peripheral...

    Incorrect

    • A 25 year old man presented with a history of headache and peripheral cyanosis. He had been living in the Himalayas for 6 months prior to this. What is the reason for his condition?

      Your Answer: Polycythaemia vera

      Correct Answer: Physiological polycythaemia

      Explanation:

      Polycythaemia is a condition that results in an increase in the total number of red blood cells (RBCs) in the blood. It can be due to myeloproliferative syndrome or due to chronically low oxygen levels or rarely malignancy. In primary polycythaemia/polycythaemia vera the increase is due to an abnormality in the bone marrow, resulting in increases RBCs, white blood cells (WBCs) and platelets. In secondary polycythaemia the increase occurs due to high levels of erythropoietin either artificially or naturally. The increase is about 6-8 million/cm3 of blood. A type of secondary polycythaemia is physiological polycythaemia where people living in high altitudes who are exposed to hypoxic conditions produce more erythropoietin as a compensatory mechanism for thin oxygen and low oxygen partial pressure.

    • This question is part of the following fields:

      • General
      • Physiology
      35.4
      Seconds
  • Question 42 - Which of the following is a likely consequence of severe diarrhoea? ...

    Correct

    • Which of the following is a likely consequence of severe diarrhoea?

      Your Answer: A decrease in the sodium content of the body

      Explanation:

      Diarrhoea can occur due to any of the numerous aetiologies, which include infectious, drug-induced, food related, surgical, inflammatory, transit-related or malabsorption. Four mechanisms have been implicated in diarrhoea: increased osmotic load, increased secretion, inflammation and decreased absorption time. Diarrhoea can result in fluid loss with consequent dehydration, electrolyte loss (Na+, K+, Mg2+, Cl–) and even vascular collapse. Loss of bicarbonate ions can lead to a metabolic acidosis.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      37.6
      Seconds
  • Question 43 - A young women following a road traffic accident suffered heavy blood loss and...

    Correct

    • A young women following a road traffic accident suffered heavy blood loss and developed subsequent anaemia. Which of the following is a consequence of this?

      Your Answer: A high reticulocyte count

      Explanation:

      Anaemia refers to a decrease in the circulating levels of haemoglobin in the blood resulting in a reduced ability of the body to transport oxygen effectively. Anaemia from blood loss results in the body further compensating by releasing stored RBCs and immature RBCs from the bone marrow. Thus resulting in a high reticulocyte count.

    • This question is part of the following fields:

      • General
      • Physiology
      17.3
      Seconds
  • Question 44 - Normally, the O2 transfer in the lungs from alveolar to capillary is perfusion-limited....

    Incorrect

    • Normally, the O2 transfer in the lungs from alveolar to capillary is perfusion-limited. In which of the following situations does it become a diffusion-limited process?

      Your Answer: Increased ventilatory rate

      Correct Answer: Pulmonary oedema

      Explanation:

      Normally, the transfer of oxygen from air spaces to blood takes place across the alveolar-capillary membrane by simple diffusion and depends entirely on the amount of blood flow (perfusion-limited process). Diseases that affect this diffusion will transform the normal process to a diffusion limited process. Thus, the diseases which cause a thickened barrier (such as pulmonary oedema due to increased extravascular lung water or asbestosis) will limit the diffusion of oxygen. Chronic obstructive lung diseases will have little effect on diffusion. Inhaling hyperbaric gas mixtures might overcome the diffusion limitation in patients with mild asbestosis or interstitial oedema, by increasing the driving force. Strenuous (not mild) exercise might also favour diffusion limitation and decrease passage time. Increasing the rate of ventilation will not have this affect but will only maintain a high oxygen gradient from air to blood.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      121.1
      Seconds
  • Question 45 - During cardiac catheterisation in a 20-year old man, the following data is obtained:...

    Incorrect

    • During cardiac catheterisation in a 20-year old man, the following data is obtained: Pressure (mmHg), O2 saturation (%) Right atrium 7 (N = 5) 90 (N = 75), Right ventricle 35/7 (N = 25/5) 90 (N = 75), Pulmonary artery 35/8 (N = 25/15), 90 (N = 75), Left atrium 7 (N = 9) 95 (N = 95), Left ventricle 110/7 (N = 110/9) 95 (N = 95), Aorta 110/75 (N = 110/75) 95 (N = 95) where N = Normal value. What is the likely diagnosis?

      Your Answer: Patent ductus arteriosus

      Correct Answer: Atrial septal defect

      Explanation:

      A congenital heart disease, ASD or atrial septal defect leads to a communication between the right and left atria due to a defect in the interatrial septum. This leads to mixing of arterial and venous blood from the right and left side of the heart. The hemodynamic significance of this defect depends on the presence of shunting of blood. Normally, the left side of the heart has higher pressure than the right as the left side has to pump blood throughout the body. A large ASD (> 9 mm) will result in a clinically significant left-to-right shunt, causing volume overload of the right atrium and ventricle, eventually leading to heart failure. Cardiac catheterization would reveal very high oxygen saturation in the right atrium, right ventricle and pulmonary artery. Eventually, the left-to-right shunt will lead to pulmonary hypertension and increased afterload in the right ventricle, along with the increased preload due to the shunted blood. This will either cause right ventricular failure, or raise the pressure in the right side of the heart to equal or more than that in the left. Elevation of right atrial pressure to that of left atrial pressure would thus lead to diminishing or complete cessation of the shunt. If left uncorrected, there will be reversal of the shunt, known as Eisenmenger syndrome, resulting in clinical signs of cyanosis as the oxygen-poor blood form right side of the heart will mix with the blood in left side and reach the peripheral vascular system.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      21.1
      Seconds
  • Question 46 - The most likely cause of prominent U waves on the electrocardiogram (ECG) of...

    Incorrect

    • The most likely cause of prominent U waves on the electrocardiogram (ECG) of a patient is:

      Your Answer: Hyponatraemia

      Correct Answer: Hypokalaemia

      Explanation:

      The U-wave, not always visible in ECGs, is thought to represent repolarisation of papillary muscles or Purkinje fibres. When seen, it is very small and occurs after the T-wave. Inverted U-waves indicate myocardial ischaemia or left ventricular volume overload. Prominent U-waves are most commonly seen in hypokalaemia. Other causes include hypercalcaemia, thyrotoxicosis, digitalis exposure, adrenaline and class 1A and 3 anti-arrhythmic agents. It can also be seen in congenital long-QT syndrome and in intracranial haemorrhage.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      44.4
      Seconds
  • Question 47 - Routine evaluation of a 38 year old gentleman showed a slightly lower arterial...

    Incorrect

    • Routine evaluation of a 38 year old gentleman showed a slightly lower arterial oxygen [pa(O2)] than the alveolar oxygen [pA(O2)]. This difference is:

      Your Answer: Is due to significant diffusion gradients

      Correct Answer: Is normal and due to shunted blood

      Explanation:

      Blood that bypasses the ventilated parts of lung and enters the arterial circulation directly is known as shunted blood. It happens in normal people due to mixing of arterial blood with bronchial and some myocardial venous blood (which drains into the left heart). Diffusion limitation and reaction velocity with haemoglobin are immeasurably small. CO2 unloading will not affect the difference between alveolar and arterial p(O2). A large VSD will result in much lower arterial O2 as compared to alveolar O2.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      17.3
      Seconds
  • Question 48 - 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: Broca’s area

      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
      8.2
      Seconds
  • Question 49 - If your EEG shows waves with a frequency range of 8-12 Hz, the...

    Correct

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

      Your 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
      13.5
      Seconds
  • Question 50 - What is a major source of fuel being oxidised by the skeletal muscles...

    Incorrect

    • What is a major source of fuel being oxidised by the skeletal muscles of a man who has undergone starvation for 7 days?

      Your Answer: Muscle triglycerides

      Correct Answer: Serum fatty acids

      Explanation:

      Starvation is the most extreme form of malnutrition. Prolonged starvation can lead to permanent organ damage and can be fatal. Starved individuals eventually lose significant fat and muscle mass as the body uses these for energy.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      30.8
      Seconds
  • Question 51 - Evaluation of a 60-year old gentleman, who has been a coal miner all...

    Correct

    • Evaluation of a 60-year old gentleman, who has been a coal miner all his life and is suspected to have pulmonary fibrosis reveals the following: normal FEV1, arterial oxygen saturation 92%, alveolar ventilation 6000 ml/min at a tidal volume of 600 ml and a breathing rate of 12 breaths/min. There are also pathological changes in lung compliance and residual volume. Which of the following is most accurate about his residual volume?

      Your Answer: Cannot be measured directly with a spirometer

      Explanation:

      Residual volume is the air left in the lungs after maximal expiration is done. Thus, this is not a part of vital capacity and cannot be measured with a spirometer directly. It can be measured by the methods such as body plethysmography or inert gas dilution. Expiratory reserve volume is vital capacity minus inspiratory capacity. Resting volume of lungs is he sum of residual volume and expiratory reserve volume. Lungs recoil inward until the recoil pressure becomes zero, which corresponds to a volume significantly lower than residual volume.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      980.2
      Seconds
  • Question 52 - Skeletal muscle fibres are divided into two basic types, type I (slow-twitch fibres)...

    Incorrect

    • Skeletal muscle fibres are divided into two basic types, type I (slow-twitch fibres) and type II (fast-twitch fibres). Fast muscle fibres do which of the following:

      Your Answer: Have relatively high endurance

      Correct Answer: Use anaerobic metabolism

      Explanation:

      Skeletal muscles are divided into two types:

      1) type I also known as the slow twitch fibres. They use oxygen for their metabolism and as a result they have a high endurance potential. To support this they have abundant mitochondria and myoglobin, so they appear red/dark.

      2) type II fibres also called fast twitch fibres, are low endurance fibres used during anaerobic metabolism. They are required for short bursts of strength and cannot sustain contractions for long periods of time.

    • This question is part of the following fields:

      • General
      • Physiology
      11
      Seconds
  • Question 53 - What is the role of factor VII in coagulation? ...

    Incorrect

    • What is the role of factor VII in coagulation?

      Your Answer: Deficiency is common

      Correct Answer: Initiates the process of coagulation in conjunction with tissue factor

      Explanation:

      The main role of factor VII is to initiate the process of coagulation along with tissue factor (TF). TF is found in the blood vessels and is not normally exposed to the bloodstream. When a vessel is injured tissue factor is exposed to blood and circulating factor VII. Factor VII is converted to VIIa by TF.

    • This question is part of the following fields:

      • General
      • Physiology
      7.1
      Seconds
  • Question 54 - Regarding the coagulation cascade, Factor VII: ...

    Correct

    • Regarding the coagulation cascade, Factor VII:

      Your 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
      67.4
      Seconds
  • Question 55 - As per the Poiseuille-Hagen formula, doubling the diameter of a vessel will change...

    Incorrect

    • As per the Poiseuille-Hagen formula, doubling the diameter of a vessel will change the resistance of the vessel from 16 peripheral resistance units (PRU) to:

      Your Answer: 4 PRU

      Correct Answer: 1 PRU

      Explanation:

      Poiseuille-Hagen formula for flow in along narrow tube states that F = (PA– PB) × (Π/8) × (1/η) × (r4/l) where F = flow, PA– PB = pressure difference between the two ends of the tube, η = viscosity, r = radius of tube and L = length of tube. Also, flow is given by pressure difference divided by resistance. Hence, R = 8ηL ÷ Πr4. Hence, the resistance of the vessel changes in inverse proportion to the fourth power of the diameter. So, if the diameter of the vessel is increased to twice the original, it will lead to decrease in resistance to one-sixteenth its initial value.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      26.2
      Seconds
  • Question 56 - Atractyloside is an inhibitor of electron transport chain. It is expected to have...

    Incorrect

    • Atractyloside is an inhibitor of electron transport chain. It is expected to have little or no effect on the functioning of which of the following cell types?

      Your Answer: Intestinal luminal cells

      Correct Answer: Red blood cells

      Explanation:

      Electron transport chain is a series of electron carriers that are embedded in the mitochondrial membrane. It is the place where ATP is made. Inhibiting the electron transport chain will stop production of ATP. Red blood cells are the only cell in the given option which do not contain ATP.

    • This question is part of the following fields:

      • General
      • Physiology
      7.1
      Seconds
  • Question 57 - 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: Small intestine

      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
      7.9
      Seconds
  • Question 58 - Which of the following is NOT a nutritional factor involved in wound healing:...

    Correct

    • Which of the following is NOT a nutritional factor involved in wound healing:

      Your Answer: Vitamin B3

      Explanation:

      Vitamin B6 is required for collagen cross-links.

      Vitamin A is required for epithelial cell proliferation.

      Zinc is required for RNA and DNA synthesis.

      Copper is required for cross-linking of collagen.

    • This question is part of the following fields:

      • Cell Injury & Wound Healing
      • Physiology
      17
      Seconds
  • Question 59 - 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: Loss of appetite

      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
      11.4
      Seconds
  • Question 60 - Most of the coagulation factors are serine proteases. Which of the following is...

    Correct

    • Most of the coagulation factors are serine proteases. Which of the following is not one of them?

      Your Answer: Factor XIII

      Explanation:

      Serine protease coagulation factors include: thrombin, plasmin, Factors X, XI and XII. Factor VIII and factor V are glycoproteins and factor XIII is a transglutaminase.

    • This question is part of the following fields:

      • General
      • Physiology
      24.2
      Seconds
  • Question 61 - Mechanical distortion, and not K+ channels are responsible for distortion of which of...

    Incorrect

    • Mechanical distortion, and not K+ channels are responsible for distortion of which of the following structures?

      Your Answer: Neuromuscular junction

      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).

    • This question is part of the following fields:

      • Neurology
      • Physiology
      5.8
      Seconds
  • Question 62 - What is the normal duration of the ST segment? ...

    Correct

    • What is the normal duration of the ST segment?

      Your Answer: 0.08 s

      Explanation:

      The ST segment lies between the QRS complex and the T-wave. The normal duration of the ST segment is 0.08 s. ST-segment elevation or depression may indicate myocardial ischaemia or infarction.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      29.5
      Seconds
  • Question 63 - QT interval in the electrocardiogram of a healthy individual is normally: ...

    Correct

    • QT interval in the electrocardiogram of a healthy individual is normally:

      Your Answer: 0.40 s

      Explanation:

      QT interval extends from beginning of the QRS complex till the end of he T-wave and normally lasts for 0.40 s. It is important in the diagnosis of long-QT and short-QT syndrome. The QT interval varies on the basis of heart rate and may need to be corrected.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      35.1
      Seconds
  • Question 64 - 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: Decreased PR interval

      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
      26
      Seconds
  • Question 65 - Which of the following muscles aid in inspiration? ...

    Incorrect

    • Which of the following muscles aid in inspiration?

      Your Answer: Diaphragm, internal and external intercostals

      Correct Answer: Diaphragm and external intercostals

      Explanation:

      The diaphragm and external intercostals are muscles of inspiration as they increase the volume of thoracic cavity and reduce the intrathoracic pressure. Muscles of expiration include abdominal muscles and internal intercostals.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      26.6
      Seconds
  • Question 66 - Bile salt reuptake principally occurs where? ...

    Incorrect

    • Bile salt reuptake principally occurs where?

      Your Answer: In the duodenum

      Correct Answer: In the ileum

      Explanation:

      90 – 95% of the bile salts are absorbed from the small intestine (mostly terminal ileum and then excreted again from the liver. This is known as the enterohepatic circulation. The entire pool recycles twice per meal and approximately 6 to 8 times per day.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      8
      Seconds
  • Question 67 - An experiment was conducted in which the skeletal muscle protein (not smooth muscle)...

    Correct

    • 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: 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
      65.4
      Seconds
  • Question 68 - 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: Decrease Decrease

      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
      20.3
      Seconds
  • Question 69 - Purkinje fibres in the heart conduct action potentials at the rate of: ...

    Correct

    • Purkinje fibres in the heart conduct action potentials at the rate of:

      Your Answer: 1.5–4.0 m/s

      Explanation:

      Purkinje fibres control the heart rate along with the sinoatrial node (SA node) and the atrioventricular node (AV node). The QRS complex is associated with the impulse passing through the Purkinje fibres. These fibres conduct action potential about six times faster than the velocity in normal cardiac muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.9
      Seconds
  • Question 70 - 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: Coxsackie B virus

      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
      16.3
      Seconds
  • Question 71 - A 30-year-old woman feels thirsty. This thirst is probably due to: ...

    Correct

    • A 30-year-old woman feels thirsty. This thirst is probably due to:

      Your Answer: Increased level of angiotensin II

      Explanation:

      Thirst is the basic need or instinct to drink. It arises from a lack of fluids and/or an increase in the concentration of certain osmolites such as salt. If the water volume of the body falls below a certain threshold or the osmolite concentration becomes too high, the brain signals thirst. Excessive thirst, known as polydipsia, along with excessive urination, known as polyuria, may be an indication of diabetes. Angiotensin II is a hormone that is a powerful dipsogen (i.e. it stimulates thirst) that acts via the subfornical organ. It increases secretion of ADH in the posterior pituitary and secretion of ACTH in the anterior pituitary.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      100.9
      Seconds
  • Question 72 - After a total colectomy and ileotomy, a 50-year old diabetic man who was...

    Correct

    • After a total colectomy and ileotomy, a 50-year old diabetic man who was a known case of diabetic nephropathy had persistent metabolic acidosis. The patient appeared well perfused, with normal vital signs and normal fluid balance. Investigations revealed:

      Sodium = 132 mmol/l

      Potassium = 6.6 mmol/l

      Creatinine = 185 μmol/l (2.16 mg/dl)

      Chloride = 109 μmol/l

      8am cortisol = 500 nmol/l (18 μg/dl)

      pH = 7.29, p(CO2) = 27 mmHg

      p(O2) = 107 mmHg

      standard bicarbonate = 12 mmol/l.

      What is the likely causes of his acidosis?

      Your Answer: Renal tubular acidosis

      Explanation:

      Acidosis here is due to low bicarbonate. The low p(CO2) is seen in compensation. The anion gap is normal, ruling out intra-abdominal ischaemia (which leads to metabolic acidosis). If it was a gastrointestinal aetiology, low potassium would be seen. The history of diabetic nephropathy predisposes to renal tubular acidosis. Type 4 (hyporeninaemic hypoaldosteronism) is associated with high potassium and is found in diabetic and hypertensive renal disease.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      68.8
      Seconds
  • Question 73 - A 40 year old man suffered severe trauma following a MVA. His BP...

    Incorrect

    • A 40 year old man suffered severe trauma following a MVA. His BP is 72/30 mmhg, heart rate of 142 beats/mins and very feeble pulse. He was transfused 3 units of blood and his BP returned to 100/70 and his heart rate slowed to 90 beats/min. What decreased after transfusion?

      Your Answer: Cardiac output

      Correct Answer: Total peripheral resistance

      Explanation:

      The patient is in hypovolemic shock, he is transfused with blood, this fluid resuscitation will result in a decreased sympathetic discharge and adequate ventricular filling which will result in the decreases TPR with an increased CO and cardiac filling pressures

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      9.7
      Seconds
  • Question 74 - 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: Vomiting

      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
      16.3
      Seconds
  • Question 75 - A 34-year old gentleman presented with acute pancreatitis to the emergency department. On...

    Incorrect

    • A 34-year old gentleman presented with acute pancreatitis to the emergency department. On enquiry, there was found to be a history of recurrent pancreatitis, eruptive xanthomas and raised plasma triglyceride levels associated with chylomicrons. Which of the following will be found deficient in this patient?

      Your Answer: Low-density lipoprotein (LDL) receptors

      Correct Answer: Lipoprotein lipase

      Explanation:

      The clinical features mentioned here suggest the diagnosis of hypertriglyceridemia due to lipoprotein lipase (LPL) deficiency. LPL aids in hydrolysing the lipids in lipoproteins into free fatty acids and glycerol. Apo-CII acts as a co-factor. Deficiency of this enzyme leads to hypertriglyceridemia.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      213
      Seconds
  • Question 76 - One sensitive indicator of heavy alcohol dependence is: ...

    Incorrect

    • One sensitive indicator of heavy alcohol dependence is:

      Your Answer: Decreased mean cell volume (MCV)

      Correct Answer: Elevated serum gamma-glutamyl transpeptidase

      Explanation:

      Elevated serum gamma-glutamyl transpeptidase (GGT) may be the only laboratory abnormality in patients who are dependent on alcohol. Heavy drinkers may also have an increased MCV.

    • This question is part of the following fields:

      • Hepatobiliary
      • Physiology
      22.1
      Seconds
  • Question 77 - 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: Atrial natriuretic peptide

      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
      27.5
      Seconds
  • Question 78 - Intravenous diazepam was administered to a man who was brought to the emergency...

    Correct

    • Intravenous diazepam was administered to a man who was brought to the emergency department with status epilepticus. He was administered 15 l/min oxygen via a reservoir bag mask. Blood investigations showed sodium = 140 mmol/l, potassium = 4 mmol/l and chloride = 98 mmol/l. His arterial blood gas analysis revealed pH 7.08, p(CO2)= 61.5 mmHg, p(O2) = 111 mmHg and standard bicarbonate = 17 mmol/l. This patient had:

      Your Answer: Mixed acidosis

      Explanation:

      Acidosis with high p(CO2) and low standard bicarbonate indicates mixed acidosis. Lower p(O2) is due to breathing of 70% oxygen. The prolonged seizures lead to lactic acidosis and the intravenous diazepam is responsible for the respiratory acidosis. Treatment includes airway manoeuvres and oxygen, assisted ventilation if needed, and treatment with fluids.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      12.9
      Seconds
  • Question 79 - During pregnancy the uterus enlarges however after delivery it regresses to its original...

    Correct

    • 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: 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
      20.6
      Seconds
  • Question 80 - Calculate the pulmonary vascular resistance in an adult male with the following parameters:...

    Incorrect

    • Calculate the pulmonary vascular resistance 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: 2.5 resistance units (mmHg/l per min)

      Correct Answer: 2.0 resistance units (mmHg/l per min)

      Explanation:

      Pulmonary vascular resistance (PVR) = (Mean pulmonary artery pressure – Pulmonary capillary wedge pressure) divided by Cardiac output. To get cardiac output, Fick’s principle needs to be applied which states that VO2 = (CO × CAO2) – (CO × CVO2) where VO2 = oxygen consumption, CO = cardiac output, CA = 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. To calculate mean pulmonary artery pressure, we use the formula: Mean pulmonary artery pressure = Diastolic pressure + 1/3(Systolic pressure – Diastolic pressure). Thus, Mean pulmonary artery pressure = 15 + 1/3(25 – 15) = 15 + 3. 33 = 18.33. Substituting these values in the first formula, PVR = 18.3–5/6.25 = 13.5/5.25 = 2.0 resistance units (mmHg/l per min) approximately.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      12.9
      Seconds
  • Question 81 - A 60 year old patient with a history of carcinoma of the head...

    Correct

    • A 60 year old patient with a history of carcinoma of the head of the pancreas, and obstructive jaundice presents with a spontaneous nose bleed and easy bruising. What is the most likely reason for this?

      Your Answer: Vitamin-K-dependent clotting factors deficiency

      Explanation:

      Vitamin K is a fat soluble vitamin requiring fat metabolism to function properly to allow for its absorption. People with obstructive jaundice develop vitamin k deficiency as fat digestion is impaired. Vit K causes carboxylation of glutamate residue and hence regulates blood coagulation including: prothrombin (factor II), factors VII, IX, X, protein C, protein S and protein Z.

    • This question is part of the following fields:

      • General
      • Physiology
      53.4
      Seconds
  • Question 82 - The most important difference between interstitial fluid and plasma is the: ...

    Incorrect

    • The most important difference between interstitial fluid and plasma is the:

      Your Answer: Concentration of sodium

      Correct Answer: Protein concentration

      Explanation:

      Interstitial fluid (or tissue fluid or intercellular fluid) is a solution that surrounds the cells of multicellular animals. It is the main component of the extracellular fluid, which also includes plasma, lymph and transcellular fluid. Plasma, the major component in blood, communicates freely with interstitial fluid through pores and intercellular clefts in capillary endothelium. Interstitial fluid consists of a water solvent containing amino acids, sugars, fatty acids, coenzymes, hormones, neurotransmitters, salts, as well as waste products from the cells. Red blood cells, platelets and plasma proteins cannot pass through the walls of the capillaries. The resulting mixture that does pass through is essentially blood plasma without the plasma proteins. Tissue fluid also contains certain types of white blood cells. Once the extracellular fluid collects into small vessels it is considered to be lymph, and the vessels that carry it back to the blood are called the lymphatic vessels. The lymphatic system returns protein and excess interstitial fluid to the circulation.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      18
      Seconds
  • Question 83 - Action potentials are used extensively by the nervous system to communicate between neurones...

    Incorrect

    • Action potentials are used extensively by the nervous system to communicate between neurones and muscles or glands. What happens during the activation of a nerve cell membrane?

      Your Answer: Potassium ions flow inward

      Correct Answer: Sodium ions flow inward

      Explanation:

      During the generation of an action potential, the membrane gets depolarized which cause the voltage gated sodium channels to open and sodium diffuses inside the neuron, resulting in the membrane potential moving towards a positive value. This positive potential will then open the voltage gated potassium channels and cause more K+ to move out decreasing the membrane potential and restoring the membrane potential to its resting value.

    • This question is part of the following fields:

      • General
      • Physiology
      36.9
      Seconds
  • Question 84 - 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: Will mainly affect HCO3 – secretion

      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
      19.9
      Seconds
  • Question 85 - A brain tumour causing blockage of the hypophyseal portal system is likely to...

    Incorrect

    • A brain tumour causing blockage of the hypophyseal portal system is likely to result in an increased secretion of which of the following hormones?

      Your Answer: Thyroid-stimulating hormone

      Correct Answer: Prolactin

      Explanation:

      The hypophyseal portal system links the hypothalamus and the anterior pituitary. With the help of this system, the anterior pituitary receives releasing and inhibitory hormones from the hypothalamus and regulates the action of other endocrine glands. One of the inhibitory hormones carried by this system is the prolactin-inhibitory hormone. In the absence of this hormone which might occur in case of a blockage of the system, prolactin secretion increases to about three times normal levels.

    • This question is part of the following fields:

      • Endocrinology
      • Physiology
      54.3
      Seconds
  • Question 86 - 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: Decrease in temperature

      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
      42.6
      Seconds
  • Question 87 - A 7-year-old boy is diagnosed with metabolic acidosis as a result of severe...

    Correct

    • A 7-year-old boy is diagnosed with metabolic acidosis as a result of severe dehydration. Which of the following conditions is most likely to cause severe dehydration and metabolic acidosis?

      Your Answer: Severe diarrhoea

      Explanation:

      Diarrhoea is defined as having three or more loose or liquid stools per day, or as having more stools than is normal for that person. Severe diarrhoea, causing fluid loss and loss of bicarbonate, will result in marked dehydration and metabolic acidosis.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      11.9
      Seconds
  • Question 88 - Which antibiotic acts by inhibiting protein synthesis? ...

    Incorrect

    • Which antibiotic acts by inhibiting protein synthesis?

      Your Answer: Cefuroxime

      Correct Answer: Erythromycin

      Explanation:

      Penicillins and cephalosporins (e.g. cefuroxime, cefotaxime, ceftriaxone) inhibit bacterial cell wall synthesis through the inhibition of peptidoglycan cross-linking.

      Macrolides (e.g. erythromycin), tetracyclines, aminoglycosides and chloramphenicol act by interfering with bacterial protein synthesis.

      Sulphonamides (e.g. trimethoprim, co-trimoxazole) work by inhibiting the synthesis of nucleic acid

    • This question is part of the following fields:

      • Pharmacology; Microbiology
      • Physiology
      17.4
      Seconds
  • Question 89 - Which of the following clinical signs will be demonstrated in a case of...

    Correct

    • Which of the following clinical signs will be demonstrated in a case of Brown-Séquard syndrome due to hemisection of the spinal cord at mid-thoracic level?

      Your Answer: Ipsilateral spastic paralysis, ipsilateral loss of vibration and proprioception (position sense) and contralateral loss of pain and temperature sensation beginning one or two segments below the lesion

      Explanation:

      Brown–Séquard syndrome results due to lateral hemisection of the spinal cord and results in a loss of motricity (paralysis and ataxia) and sensation. The hemisection of the cord results in a lesion of each of the three main neural systems: the principal upper motor neurone pathway of the corticospinal tract, one or both dorsal columns and the spinothalamic tract. As a result of the injury to these three main brain pathways the patient will present with three lesions. The corticospinal lesion produces spastic paralysis on the same side of the body (the loss of moderation by the upper motor neurons). The lesion to fasciculus gracilis or fasciculus cuneatus results in ipsilateral loss of vibration and proprioception (position sense). The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion. At the lesion site, all sensory modalities are lost on the same side, and an ipsilateral flaccid paralysis.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      6.6
      Seconds
  • Question 90 - What percentage of cardiac output is delivered to the skin? ...

    Incorrect

    • What percentage of cardiac output is delivered to the skin?

      Your Answer: 12%

      Correct Answer: 2%

      Explanation:

      Making up 4-5% of total body weight, the skin receives approximately 2% of cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      4.6
      Seconds
  • Question 91 - Which of the following organelles have the capacity to regenerate and spontaneously replicate?...

    Incorrect

    • Which of the following organelles have the capacity to regenerate and spontaneously replicate?

      Your Answer: Rough endoplasmic reticulum

      Correct Answer: Mitochondrion

      Explanation:

      A mitochondria is a membrane bound organelle found in eukaryotic cells. They are called the powerhouse of the cell and are the place where ATP is formed from energy generated through metabolism. They are capable of replication as well as repair and regeneration.

    • This question is part of the following fields:

      • General
      • Physiology
      20.8
      Seconds
  • Question 92 - A sudden loud sound is more likely to result in cochlear damage than...

    Incorrect

    • A sudden loud sound is more likely to result in cochlear damage than a slowly developing loud sound. This is because:

      Your Answer: A sudden sound carries more energy

      Correct Answer: There is a latent period before the attenuation reflex can occur

      Explanation:

      On transmission of a loud sound into the central nervous system, an attenuation reflex occurs after a latent period of 40-80 ms. This reflex contracts the two muscles that pull malleus and stapes closer, developing a high degree of rigidity in the entire ossicular chain. This reduces the ossicular conduction of low frequency sounds to the cochlea by 30-40 decibels. In this way, the cochlea is protected from damage due to loud sounds (these are low frequency sounds) when they develop slowly.

    • This question is part of the following fields:

      • Neurology
      • Physiology
      16.5
      Seconds
  • Question 93 - A 26-year-old female patient had the following blood report: RBC count =...

    Correct

    • A 26-year-old female patient had the following blood report: RBC count = 4. 0 × 106/μl, haematocrit = 27% and haemoglobin = 11 g/dl, mean corpuscular volume (MCV) = 90 fl, mean corpuscular haemoglobin concentration (MCHC) = 41 g/dl. Further examination of blood sample revealed increased osmotic fragility of the erythrocytes. Which of the following is the most likely cause of this patient’s findings?

      Your Answer: Spherocytosis

      Explanation:

      Spherocytes are small rounded RBCs. It is due to an inherited defect of the RBC cytoskeleton membrane tethering proteins. Membrane blebs form that are lost over time and cells become round instead of biconcave. As it is a normochromic anaemia, the MCV is normal. it is diagnosed by osmotic fragility test which reveals increased fragility in a hypotonic solution.

    • This question is part of the following fields:

      • General
      • Physiology
      6.3
      Seconds
  • Question 94 - The mechanism of action of streptokinase involves: ...

    Incorrect

    • The mechanism of action of streptokinase involves:

      Your Answer: Activation of factor X

      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
      7.4
      Seconds
  • Question 95 - 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: Anaemic hypoxia

      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
      4.3
      Seconds
  • Question 96 - What is the basic chemical reaction that takes place in the breakdown of...

    Incorrect

    • What is the basic chemical reaction that takes place in the breakdown of complex foodstuffs?

      Your Answer: Neutralisation

      Correct Answer: Hydrolysis

      Explanation:

      Breakdown of complex food into simpler compounds is achieved by hydrolysis, with the help of different enzymes specific for different compounds.

    • This question is part of the following fields:

      • Gastroenterology
      • Physiology
      5.9
      Seconds
  • Question 97 - Which organ is most vulnerable to haemorrhagic shock? ...

    Correct

    • Which organ is most vulnerable to haemorrhagic shock?

      Your Answer: Kidneys

      Explanation:

      At rest, the brain receives 15% cardiac output, muscles 15%, gastrointestinal tract 30% and kidneys receive 20%. However, if normalised by weight, the largest specific blood flow is received by the kidneys at rest (400 ml/min x 100g), making them highly vulnerable in the case of a haemorrhagic shock.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      4.4
      Seconds
  • Question 98 - what is the cause of a prolonged PT(prothrombin time)? ...

    Incorrect

    • what is the cause of a prolonged PT(prothrombin time)?

      Your Answer: Heparin therapy

      Correct Answer: Liver disease

      Explanation:

      PT measure the intrinsic pathway of coagulation. It determines the measure of the warfarin dose regime, liver disease and vit K deficiency status along with the clotting tendency of blood. PT measured factors are II,V,VII,X and fibrinogen. It is used along with aPTT which measure the intrinsic pathway.

    • This question is part of the following fields:

      • General
      • Physiology
      18.9
      Seconds
  • Question 99 - After a prolonged coronary artery bypass surgery, a 60-year old gentleman was transfused...

    Incorrect

    • After a prolonged coronary artery bypass surgery, a 60-year old gentleman was transfused 3 units of fresh-frozen plasma and 2 units of packed red cells. Two days later, the nurse noticed that he was tachypnoeic and chest X-ray showed signs consistent with adult respiratory distress syndrome. Which of the following variables will be low in this patient?

      Your Answer: Alveolar–arterial p(O2) difference

      Correct Answer: Compliance of the lung

      Explanation:

      Acute or adult respiratory distress syndrome (ARDS) is a reaction to several forms of lung injuries and is commonly associated with sepsis and SIRS (systemic inflammatory response syndrome), severe traumatic injury, severe head injury, narcotics overdose, drowning, pulmonary contusion, and multiple blood transfusions. There is an increase in risk due to pre-existing liver disease or coagulation abnormalities. It results due to indirect toxic effects of neutrophil-derived inflammatory mediators in the lungs. ARDS is defined by the 1994 American–European Consensus Committee as the acute onset of bilateral infiltrates on chest X-ray, a partial pressure of arterial oxygen (pa(O2)) to fraction of inspired oxygen Fi(O2) ratio of less than 200 mmHg and a pulmonary artery occlusion pressure of less than 18 or the absence of clinical evidence of left arterial hypertension. ARDS is basically pulmonary oedema in the absence of volume overload or poor left ventricular function. This is different from acute lung injury, which shows a pa(O2)/Fi(O2) ratio of less than 300 mmHg. Pathogenesis of ARDS starts from damage to alveolar epithelium and vascular endothelium, causing increased permeability. Damage to surfactant-producing type II cells disrupts the production and function of pulmonary surfactant, causing micro atelectasis and poor gas exchange. There is a decrease in lung compliance and increase in work of breathing. Eventually, there is resorption of alveolar oedema, regeneration of epithelial cells, proliferation and differentiation of type II alveolar cells and alveolar remodelling. Some show resolution and some progress to fibrosing alveolitis, which involves the deposition of collagen in alveolar, vascular and interstitial spaces.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      75.5
      Seconds
  • Question 100 - A 40-year old lady with a flail chest due to trauma was breathing...

    Incorrect

    • A 40-year old lady with a flail chest due to trauma was breathing with the help of a mechanical ventilator in the ICU, and was heavily sedated on muscle relaxants. Due to sudden power failure, a nurse began to hand-ventilate the patient with a Ambu bag. What change will occur in the following parameters: (Arterial p(CO2), pH) in the intervening period between power failure and hand ventilation?

      Your Answer:

      Correct Answer: Increase, Decrease

      Explanation:

      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. Respiratory acidosis can be acute or chronic. In acute respiratory acidosis, the p(CO2) is raised above the upper limit of normal (over 45 mm Hg) with 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). The given problem represents acute respiratory acidosis and thus, will show a increase in arterial p(CO2) and decrease in pH.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

General (18/26) 69%
Physiology (63/99) 64%
Gastroenterology (11/14) 79%
Cardiovascular (9/19) 47%
Neurology (8/11) 73%
Fluids & Electrolytes (5/8) 63%
Respiratory (8/14) 57%
Endocrinology (2/3) 67%
Endocrine (1/1) 100%
Cell Injury & Wound Healing (0/1) 0%
Hepatobiliary (1/1) 100%
Pharmacology; Microbiology (0/1) 0%
Passmed