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  • Question 1 - Under normal conditions, what is the major source of energy of cardiac muscles?...

    Correct

    • Under normal conditions, what is the major source of energy of cardiac muscles?

      Your Answer: Fatty acids

      Explanation:

      Under basal conditions, most of the energy needed by cardiac muscle for metabolism is derived from fats (60%), 35% by carbohydrates, and 5% by ketones and amino acids. However, after intake of large amounts of glucose, lactate and pyruvate are mainly used. During prolonged starvation, fat acts as the primary source. 50% of the used lipids are sourced from circulating fatty acids.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      7
      Seconds
  • Question 2 - 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
      7.3
      Seconds
  • Question 3 - A 47-year old-woman diagnosed with pancreatitis presented to the emergency department complaining of...

    Correct

    • A 47-year old-woman diagnosed with pancreatitis presented to the emergency department complaining of a worsening shortness of breath, fever, agitation and cough. Oxygen saturation was 67% in room air. Her respiratory status continued to deteriorate therefore she was intubated. She was admitted to the intensive care unit for management. Chest X-ray demonstrated bilateral perihilar opacities. The patient failed conventional treatment and died several days later. At autopsy, the lung shows growth of type 2 pneumocytes and thickened alveolar walls. What is the most probable diagnosis?

      Your Answer: Adult respiratory distress syndrome

      Explanation:

      Acute (or adult) respiratory distress syndrome (ARDS) is a life-threatening lung condition characterised by a non-cardiogenic pulmonary oedema that leads to acute respiratory failure. The most common risk factors for ARDS include trauma with direct lung injury, sepsis, pneumonia, pancreatitis, burns, drug overdose, massive blood transfusion and shock. Acute onset of dyspnoea with hypoxemia, anxiety and agitation is typical. Chest X ray most commonly demonstrates bilateral pulmonary infiltrates. Histological changes include the exudative, proliferative and fibrotic phase. ARDS is mainly a clinical diagnosis.

    • This question is part of the following fields:

      • Pathology
      • Respiratory
      125
      Seconds
  • Question 4 - Different portions of the renal tubule have varying degrees of water permeability. Which...

    Correct

    • Different portions of the renal tubule have varying degrees of water permeability. Which of the following renal sites is characterised by low water permeability under normal circumstances?

      Your Answer: Thick ascending limb of the loop of Henlé

      Explanation:

      Within the nephron of the kidney, the ascending limb of the loop of Henle is a segment of the loop of Henle downstream of the descending limb, after the sharp bend of the loop. Both the thin and the thick ascending limbs of the loop of Henlé have very low permeability to water. Since there are no regulatory mechanisms to alter its permeability, it remains poorly permeable to water under all circumstances. Sodium and chloride are transported out of the luminal fluid into the surrounding interstitial spaces, where they are reabsorbed. Water must remain behind because it is not reabsorbed, so the solute concentration becomes less and less (the luminal fluid becomes more dilute). This is one of the principal mechanisms (along with diminution of ADH secretion) for the production of a dilute, hypo-osmotic urine (water diuresis).

    • This question is part of the following fields:

      • Physiology
      • Renal
      43.3
      Seconds
  • Question 5 - A 59-year-old woman with hyperaldosteronism is prescribed a diuretic. Which of the following...

    Correct

    • A 59-year-old woman with hyperaldosteronism is prescribed a diuretic. Which of the following diuretics promotes diuresis by opposing the action of aldosterone?

      Your Answer: Potassium-sparing diuretic

      Explanation:

      The term potassium-sparing refers to an effect rather than a mechanism or location. Potassium-sparing diuretics act by either antagonising the action of aldosterone (spironolactone) or inhibiting Na+ reabsorption in the distal tubules (amiloride). This group of drugs is often used as adjunctive therapy, in combination with other drugs, for the management of chronic heart failure. Spironolactone, the first member of the class, is also used in the management of hyperaldosteronism (including Conn’s syndrome) and female hirsutism (due to additional antiandrogen actions).

    • This question is part of the following fields:

      • Physiology
      • Renal
      12.5
      Seconds
  • Question 6 - Which of the following conditions causes an elevation of the pH in the...

    Correct

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

      Your 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
      56.1
      Seconds
  • Question 7 - Diuretics that act on the ascending limb of the loop of Henle produce:...

    Incorrect

    • Diuretics that act on the ascending limb of the loop of Henle produce:

      Your Answer: Reduced absorption of water

      Correct Answer: Reduced active transport of sodium

      Explanation:

      The loop of Henlé leads from the proximal convoluted tubule to the distal convoluted tubule. Its primary function uses a counter current multiplier mechanism in the medulla to reabsorb water and ions from the urine. It can be divided into four parts:

      1. Descending limb of loop of HenlĂ© – low permeability to ions and urea, while being highly permeable to water

      2. Thin ascending limb of loop of HenlĂ© – not permeable to water, but it is permeable to ions

      3. Medullary thick ascending limb of loop of HenlĂ© – sodium (Na+), potassium (K+) and chloride (Cl–) ions are reabsorbed by active transport. K+ is passively transported along its concentration gradient through a K+ channel in the basolateral aspect of the cells, back into the lumen of the ascending limb.

      4. The cortical thick ascending limb – the site of action where loop diuretics such as furosemide block the K+/Na+/2Cl− co-transporters = reduced active transport.

    • This question is part of the following fields:

      • Physiology
      • Renal
      93.3
      Seconds
  • Question 8 - Which of the following variables are needed to calculate inspiratory reserve volume of...

    Correct

    • Which of the following variables are needed to calculate inspiratory reserve volume of a patient?

      Your Answer: Tidal volume, vital capacity and expiratory reserve volume

      Explanation:

      Vital capacity = inspiratory reserve volume + tidal volume + expiratory reserve volume. Thus, inspiratory reserve volume can be calculated if tidal volume, vital capacity and expiratory reserve volume are known.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      9.8
      Seconds
  • Question 9 - An 18 -year-old female is diagnosed with folliculitis in the left axilla. What...

    Correct

    • An 18 -year-old female is diagnosed with folliculitis in the left axilla. What is the most likely organism that could cause this condition?

      Your Answer: Staphylococcus aureus

      Explanation:

      Folliculitis is the inflammation of the hair follicles. It is usually caused by Staphylococcus infection.

    • This question is part of the following fields:

      • Microbiology
      • Pathology
      25.8
      Seconds
  • Question 10 - A diabetic 58-year-old man, after the injection of radiographic contrast, has a decreased...

    Correct

    • A diabetic 58-year-old man, after the injection of radiographic contrast, has a decreased urine output and decreased level of consciousness. Which of the following conditions has he most likely developed

      Your Answer: Acute tubular necrosis

      Explanation:

      Acute tubular necrosis (ATN) involves damage to the tubule cells of the kidneys and is the most common cause of acute kidney injury. ATN in the majority of the cases is caused by ischaemia of the kidneys due to lack of perfusion and oxygenation but it may also occur due to poison or harmful substance. Contrast used for radiology may cause ATN in patients with several risk factors e.g. diabetic nephropathy. Symptoms may include oliguria, nausea, fluid retention, fatigue and decreased consciousness.

    • This question is part of the following fields:

      • Pathology
      • Renal
      32.1
      Seconds
  • Question 11 - Which portion of the renal tubule absorbs amino acids and glucose? ...

    Correct

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

      Your Answer: Proximal convoluted tubule

      Explanation:

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

    • This question is part of the following fields:

      • Physiology
      • Renal
      36.5
      Seconds
  • Question 12 - 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
      9.6
      Seconds
  • Question 13 - A 30-year-old woman is diagnosed with Hodgkin's lymphoma. Which of the following chemotherapy...

    Incorrect

    • A 30-year-old woman is diagnosed with Hodgkin's lymphoma. Which of the following chemotherapy regimens would be used in this case?

      Your Answer: CHOP

      Correct Answer: ABVD

      Explanation:

      ABVD is a chemotherapy regimen used in the first-line treatment of Hodgkin’s lymphoma. It consists of concurrent treatment with the chemotherapy drugs, adriamycin, bleomycin, vinblastine and dacarbazine. It supplanted the older MOPP protocol.

    • This question is part of the following fields:

      • Pathology
      • Pharmacology
      10.4
      Seconds
  • Question 14 - A 30-year-old woman feels thirsty. This thirst is probably due to: ...

    Incorrect

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

      Your Answer: Hypoglycaemia

      Correct 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
      9.3
      Seconds
  • Question 15 - A victim of road traffic accident presented to the emergency department with a...

    Incorrect

    • A victim of road traffic accident presented to the emergency department with a blood pressure of 120/90 mm Hg, with a drop in systolic pressure to 100 mm Hg on inhalation. This is known as:

      Your Answer: Pulsus bisferiens

      Correct Answer: Pulsus paradoxus

      Explanation:

      Weakening of pulse with inhalation and strengthening with exhalation is known as pulsus paradoxus. This represents an exaggeration of the normal variation of the pulse in relation to respiration. It indicates conditions such as cardiac tamponade and lung disease. The paradox refers to the auscultation of extra cardiac beats on inspiration, as compared to the pulse. Due to a decrease in blood pressure, the radial pulse becomes impalpable along with an increase in jugular venous pressure height (Kussmaul sign). Normal systolic blood pressure variation (with respiration) is considered to be >10 mmHg. It is >100 mmHg in Pulsus paradoxus. It is also predictive of the severity of cardiac tamponade.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      23.9
      Seconds
  • Question 16 - The renal tubule is the portion of the nephron that contains the fluid...

    Incorrect

    • The renal tubule is the portion of the nephron that contains the fluid that has been filtered by the glomerulus. Which of the following substances is actively secreted into the renal tubules?

      Your Answer: Glucose

      Correct Answer: Potassium

      Explanation:

      The renal corpuscle filters out solutes from the blood, delivering water and small solutes to the renal tubule for modification. In normal circumstances more than 90% of the filtered load of K is reabsorbed by the proximal tubules and loops of Henlé and almost all K appearing in the urine has been secreted by the late distal tubules and collecting tubules. So the rate of excretion is usually independent of the rate of filtration, but is closely tied to the rate of secretion and control of K excretion, largely accomplished by control of the secretion rate. Around 65–70% of the filtered potassium is reabsorbed along with water in the proximal tubule and the concentration of potassium in the tubular fluid varies little from that of the plasma.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      22.1
      Seconds
  • Question 17 - Chest X-ray of a 45-year old gentleman with a week history of pleurisy...

    Incorrect

    • Chest X-ray of a 45-year old gentleman with a week history of pleurisy showed a small pneumothorax with moderate-sized pleural effusion. Arterial blood gas analysis showed p(CO2) = 23 mmHg, p(O2) = 234.5 mmHg, standard bicarbonate = 16 mmol/l. What are we most likely dealing with?

      Your Answer: Mixed acidosis

      Correct Answer: Compensated respiratory alkalosis

      Explanation:

      Normal pH with low p(CO2) and low standard bicarbonate could indicate either compensated respiratory alkalosis or a compensated metabolic acidosis. However, the history of hyperventilation for 5 days (pleurisy) favours compensated respiratory alkalosis. Compensated metabolic acidosis would have been likely in a diabetic patient with fever, vomiting and high glucose (diabetic ketoacidosis).

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      25.2
      Seconds
  • Question 18 - Which of these conditions is mithramycin used for? ...

    Incorrect

    • Which of these conditions is mithramycin used for?

      Your Answer: Fever

      Correct Answer: Hypercalcaemia of malignancy

      Explanation:

      Mithramycin or Plicamycin is a tricyclic pentaglycosidic antibiotic derived from Streptomyces strains. It inhibits RNA and protein synthesis by adhering to DNA. It is used as a fluorescent dye and as an antineoplastic agent. It is also used to reduce hypercalcaemia, especially caused by malignancy. Plicamycin is currently used in multiple areas of research, including cancer cell apoptosis and as a metastasis inhibitor.

    • This question is part of the following fields:

      • Pathology
      • Pharmacology
      48.7
      Seconds
  • Question 19 - Calculate the stroke volume in an adult male with the following parameters:

    Heart...

    Incorrect

    • Calculate the stroke volume 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: 75 ml

      Correct Answer: 90 ml

      Explanation:

      Fick’s principle states that, VO2 = (CO × CAO2) – (CO × CVO2) where VO2 = oxygen consumption, CO = cardiac output, CAO2 = oxygen concentration of arterial blood and CVO2 = oxygen concentration of venous blood. Thus, CO = VO2/CAO2– CVO2, CO = 500/0.24–0.16, CO = 500/0.8, CO = 6.25 l/min. Cardiac output is also given by product of stroke volume and heart rate. Thus, stroke volume = cardiac output / heart rate = 6.25/70 × 1000 stroke volume = 90 ml approximately.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      8.8
      Seconds
  • Question 20 - There are several mechanisms involved in the transport of sodium ions from blood...

    Incorrect

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

      Your Answer: Active transport through endothelial cell membranes

      Correct Answer: Diffusion through channels between endothelial cells

      Explanation:

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

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      8.4
      Seconds
  • Question 21 - A 56-year-old woman weighs 75 kg. In this patient, total body water, intracellular...

    Correct

    • A 56-year-old woman weighs 75 kg. In this patient, total body water, intracellular fluid and extracellular fluid are respectively:

      Your Answer: 45 l, 30 l, 15 l

      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. The total body water (TBW) content of humans is approximately 60% of body weight. Two-thirds is located in the intracellular and one-third in the extracellular compartment. So, in a 75-kg individual, TBW = 60 Ă— 75/100 = 45 l. Intracellular content = 2/3 Ă— 45 = 30 l and extracellular content = 1/3 Ă— 45 = 15 l.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      4.2
      Seconds
  • Question 22 - A 30 year old female presented in the emergency with an irregular pulse....

    Incorrect

    • A 30 year old female presented in the emergency with an irregular pulse. Her ECG showed absent P-waves with irregular RR interval. What is the most likely diagnosis?

      Your Answer: Ventricular tachycardia

      Correct Answer: Atrial fibrillation

      Explanation:

      Atrial fibrillation is one of the most common cardiac arrhythmias. It is often asymptomatic but may present with symptoms of palpitations, fainting, chest pain and heart failure. Characteristic findings are: absence of P-waves, unorganised electrical activity in their place, irregularity of RR interval due to irregular conduction of impulses to the ventricles and if paroxysmal AF is suspected, episodes may be documented with the use of Holter monitoring

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      6.7
      Seconds
  • Question 23 - Whilst snorkelling, a 30-year old gentleman has the respiratory rate of 10/min, tidal...

    Incorrect

    • Whilst snorkelling, a 30-year old gentleman has the respiratory rate of 10/min, tidal volume of 550 ml and an effective anatomical dead space of 250 ml. Which of the following will bring about a maximum increase in his alveolar ventilation?

      Your Answer: A 2x increase in tidal volume

      Correct Answer: A 2x increase in tidal volume and a shorter snorkel

      Explanation:

      Alveolar ventilation = respiratory rate Ă— (tidal volume − anatomical dead space volume). Increase in respiratory rate simply causes movement of air in the anatomical dead space, with no contribution to the alveolar ventilation. By use of a shorter snorkel, the effective anatomical dead space will decrease and will cause a maximum rise in alveolar ventilation along with doubling of tidal volume.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      9.3
      Seconds
  • Question 24 - Gastric acid secretion is stimulated by which of the following? ...

    Correct

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

      Your 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
      10.9
      Seconds
  • Question 25 - A 43-year-old diabetic man complains of headaches, palpitations, anxiety, abdominal pain and weakness....

    Incorrect

    • A 43-year-old diabetic man complains of headaches, palpitations, anxiety, abdominal pain and weakness. He is administered sodium bicarbonate used to treat:

      Your Answer: Hypokalaemia

      Correct Answer: Metabolic acidosis

      Explanation:

      Sodium bicarbonate is indicated in the management of metabolic acidosis, which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis. Bicarbonate is given at 50-100 mmol at a time under scrupulous monitoring of the arterial blood gas readings. This intervention, however, has some serious complications including lactic acidosis, and in those cases, should be used with great care.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      9.5
      Seconds
  • Question 26 - 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
      6.9
      Seconds
  • Question 27 - A 76-year-old man with a urinary tract obstruction due to prostatic hyperplasia develops...

    Correct

    • A 76-year-old man with a urinary tract obstruction due to prostatic hyperplasia develops acute renal failure. Which of the following physiological abnormalities of acute renal failure will be most life threatening for this patient?

      Your Answer: Acidosis

      Explanation:

      Acute renal failure (ARF) is a rapid loss of renal function due to damage to the kidneys, resulting in retention of nitrogenous (urea and creatinine) and non-nitrogenous waste products that are normally excreted by the kidney. This accumulation may be accompanied by metabolic disturbances, such as metabolic acidosis and hyperkalaemia, changes in body fluid balance and effects on many other organ systems. Metabolic acidosis and hyperkalaemia are the two most serious biochemical manifestations of acute renal failure and may require medical treatment with sodium bicarbonate administration and antihyperkalaemic measures. If not appropriately treated these can be life-threatening. ARF is diagnosed on the basis of characteristic laboratory findings, such as elevated blood urea nitrogen and creatinine, or inability of the kidneys to produce sufficient amounts of urine.

    • This question is part of the following fields:

      • Physiology
      • Renal
      5.5
      Seconds
  • Question 28 - Calculate the resistance of the artery if the pressure at one end is...

    Incorrect

    • 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: 0.05

      Correct 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
      12.3
      Seconds
  • Question 29 - 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: Right atrial pressure

      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
      7.8
      Seconds
  • Question 30 - The blood-brain barrier is a membrane that separates the circulating blood from the...

    Incorrect

    • The blood-brain barrier is a membrane that separates the circulating blood from the brain extracellular fluid in the central nervous system (CNS). Which of the following statements regarding the blood– brain barrier is CORRECT?

      Your Answer: It permits carbon dioxide to pass via facilitated diffusion

      Correct Answer: It breaks down in areas of brain that are infected

      Explanation:

      The blood–brain barrier is a membrane that controls the passage of substances from the blood into the central nervous system. It is a physical barrier between the local blood vessels and most parts of the central nervous system and stops many substances from travelling across it. During meningitis, the blood–brain barrier may be disrupted. This disruption may increase the penetration of various substances (including either toxins or antibiotics) into the brain. A few regions in the brain, including the circumventricular organs, do not have a blood–brain barrier.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      7.8
      Seconds
  • Question 31 - How much blood can the pulmonary vessels of a 45-year-old healthy man accommodate...

    Incorrect

    • How much blood can the pulmonary vessels of a 45-year-old healthy man accommodate when he is at rest?

      Your Answer: 2000 ml

      Correct Answer: 500 ml

      Explanation:

      Pulmonary circulation is the portion of the cardiovascular system which carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. The vessels of the pulmonary circulation are very compliant (easily distensible) and so typically accommodate about 500 ml of blood in an adult man. This large lung blood volume can serve as a reservoir for the left ventricle, particularly during periods when left ventricular output momentarily exceeds venous return.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      8.4
      Seconds
  • Question 32 - Calculate the pulmonary vascular resistance in an adult male with the following parameters:...

    Correct

    • 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: 2.0 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
      8.8
      Seconds
  • Question 33 - A 45 year old women has a 4 cm non tender mass in...

    Incorrect

    • A 45 year old women has a 4 cm non tender mass in her right breast which is fixed to the chest wall. Another 2cm non-tender mass is palpable in the left axilla. Chest x ray reveals multiple nodules ranging from 0.5 - 0.2 cm in both the lungs. What is the stage of her disease?

      Your Answer: T2 N1 M0

      Correct Answer: T4 N1 M1

      Explanation:

      This woman has an invasive primary tumour mass with axillary node and lung metastases, making this stage T4 N1 M1. Looking at the other stems, T1 N1 M0 signifies a small primary cancer with nodal metastases but no distant metastases; T1 N0 M1 signifies a small primary cancer with no lymph node metastases but with distant metastases; T2 N1 M0 signifies a larger primary cancer with nodal metastases but no distant metastases; and T3 N0 M0 indicates a larger primary cancer with no metastases to either lymph nodes or to distant sites.

    • This question is part of the following fields:

      • Neoplasia; Female Health
      • Pathology
      10.4
      Seconds
  • Question 34 - Which of the following is responsible for the maximum increase in total peripheral...

    Incorrect

    • Which of the following is responsible for the maximum increase in total peripheral resistance on sympathetic stimulation?

      Your Answer: Both arteries and veins

      Correct Answer: Arterioles

      Explanation:

      Arterioles are also known as the resistance vessels as they are responsible for approximately half the resistance of the entire systemic circulation. They are richly innervated by the autonomic nervous system and hence, will bring about the maximum increase in peripheral resistance on sympathetic stimulation.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      8.9
      Seconds
  • Question 35 - A 45-year-old man with short bowel syndrome requires parenteral nutrition. The solution of...

    Incorrect

    • A 45-year-old man with short bowel syndrome requires parenteral nutrition. The solution of choice for parenteral nutrition is:

      Your Answer: Darrow’s solution

      Correct Answer: Crystalline amino acids

      Explanation:

      Total parenteral nutrition (TPN), is the practice of feeding a person intravenously, circumventing the gut. It is normally used in the following situations: surgery, when feeding by mouth is not possible, when a person’s digestive system cannot absorb nutrients due to chronic disease or if a person’s nutrient requirement cannot be met by enteral feeding and supplementation. A sterile bag of nutrient solution, between 500 ml and 4L, is provided. The pump infuses a small amount (0.1–10 ml/h) continuously to keep the vein open. The nutrient solution consists of water, glucose, salts, amino acids, vitamins and sometimes emulsified fats. Ideally each patient is assessed individually before commencing on parenteral nutrition, and a team consisting of doctors, nurses, clinical pharmacists and dietitians evaluate the patient’s individual data and decide what formula to use and at what rate.

    • This question is part of the following fields:

      • Fluids & Electrolytes
      • Physiology
      8.9
      Seconds
  • Question 36 - A 31-year-old woman is diagnosed with adrenal hyperplasia, and laboratory samples are taken...

    Incorrect

    • A 31-year-old woman is diagnosed with adrenal hyperplasia, and laboratory samples are taken to measure serum aldosterone and another substance. Which is most likely to be the other test that was prescribed to this patient?

      Your Answer: Plasma prolactin

      Correct Answer: Plasma renin

      Explanation:

      The evaluation of a patient in whom hyperaldosteronism is first to determine that hyperaldosteronism is present (serum aldosterone) and, if it is present, to differentiate primary from secondary causes of hyperaldosteronism. The aldosterone-to-renin ratio (ARR) is the most sensitive means of differentiating primary from secondary causes of hyperaldosteronism as it is abnormally increased in primary hyperaldosteronism, and decreased or normal but with high renin levels in secondary hyperaldosteronism.

    • This question is part of the following fields:

      • Physiology
      • Renal
      12.6
      Seconds
  • Question 37 - During strenuous exercise, what else occurs besides tachycardia? ...

    Incorrect

    • During strenuous exercise, what else occurs besides tachycardia?

      Your Answer: Rise in mixed venous blood O2 saturation

      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
      13.7
      Seconds
  • Question 38 - Which of these conditions causes haematuria, hypertension and proteinuria in children, usually after...

    Incorrect

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

      Your Answer: Bladder stones

      Correct Answer: Acute nephritic syndrome

      Explanation:

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

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

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

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

      Multisystem diseases.

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

    • This question is part of the following fields:

      • Physiology
      • Renal
      4.3
      Seconds
  • Question 39 - A 23-year-old woman decides to donate a kidney through a kidney chain. Which...

    Incorrect

    • A 23-year-old woman decides to donate a kidney through a kidney chain. Which of the following indices would be expected to be decreased in the donor after full recovery from the operation?

      Your Answer:

      Correct Answer: Creatinine clearance

      Explanation:

      Since medication to prevent rejection is so effective, donors do not need to be similar to their recipient. Most donated kidneys come from deceased donors; however, the utilisation of living donors is on the rise. Most problems encountered with live donation are associated with the donor. Firstly, there are the potentially harmful investigative procedures carried out in the assessment phase, the most hazardous being renal angiography, where there is cannulation of the artery and injection of a radio-opaque dye to determine the blood supply to the kidney. Secondly, there are the short-term risks of nephrectomy surgery. According to the literature, there is a mortality rate of between 1 in 1600 and 1 in 3000, but this is no more than is associated with any anaesthetic. In the initial postoperative period creatinine clearance may be decreased but this recovers fully over a few weeks to months. Long-term complications include prolonged wound pain.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds
  • Question 40 - Purkinje fibres in the heart conduct action potentials at the rate of: ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (9/10) 90%
Physiology (26/32) 81%
Cell Injury & Wound Healing (1/1) 100%
Pathology (4/6) 67%
Respiratory (4/5) 80%
Renal (7/9) 78%
Fluids & Electrolytes (6/8) 75%
Microbiology (1/1) 100%
Pharmacology (1/2) 50%
Endocrine (1/1) 100%
Neoplasia; Female Health (0/1) 0%
Passmed