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  • Question 1 - A 24-year-old athlete drinks a 500 ml hypertonic sports drink before an endurance...

    Correct

    • A 24-year-old athlete drinks a 500 ml hypertonic sports drink before an endurance event he participates in.Which of the following effects will this cause?

      Your Answer: The interstitial fluid becomes more concentrated

      Explanation:

      Osmosis is the passive movement of water across a semipermeable membrane from a region of low solute concentration to a region of higher solute concentration.When hypertonic fluid is ingested:The plasma becomes CONCENTRATED. The cells lose water and shrinkThe intracellular fluid becomes more concentrated.Water and ions move freely from the plasma into the interstitial fluid and the interstitial fluid becomes more concentrated. The increased osmotic potential draws water out of the cells.

    • This question is part of the following fields:

      • Basic Cellular Physiology
      • Physiology
      14.2
      Seconds
  • Question 2 - Where: Capillary hydrostatic pressure is (P c) Hydrostatic pressure in the interstices is (P I...

    Incorrect

    • Where: Capillary hydrostatic pressure is (P c) Hydrostatic pressure in the interstices is (P I )Plasma oncotic pressure is (π p) Interstitial oncotic pressure is (π i)Which of the following formulas best represents fluid flow at the capillary bed?

      Your Answer: Volume / min = (P c - P i ) - (π i - π p )

      Correct Answer: Volume / min = (P c - P i ) - (π p - π i )

      Explanation:

      Starling’s equation for fluid filtration describes fluid flow at the capillary bed.Filtration forces (capillary hydrostatic pressure and interstitial oncotic pressure) stimulate fluid movement out of the capillary, while resorption forces promote fluid movement into the capillary (interstitial hydrostatic pressure and plasma oncotic pressure). Although the forces fluctuate along the length of the capillary bed, overall filtration is achieved.At the capillary bed, there is fluid movement.The reflection coefficient (σ), the surface area accessible (S), and the hydraulic conductance of the wall (Lp) are frequently used to account for the endothelium’s semi-permeability, yielding:Volume / min = LpS [(Pc- Pi) –  σ(πp– πi)]Volume /min = (Pc-Pi) – (πp–πi) describes the fluid circulation at the capillaries.Where:Pc= capillary hydrostatic pressurePi= interstitial hydrostatic pressureπp= plasma oncotic pressureπi= interstitial oncotic pressure

    • This question is part of the following fields:

      • Cardiovascular Physiology
      • Physiology
      33.4
      Seconds
  • Question 3 - The flow of ions across a cell membrane causes electrical activity in biological...

    Incorrect

    • The flow of ions across a cell membrane causes electrical activity in biological tissues. Excitable tissues are specialized tissues that may generate a significant electrical signal called an action potential, which is followed by a refractory period.Which set of ion channels is responsible for the refractory period? 

      Your Answer: Non-selective cation channels

      Correct Answer: Sodium channels

      Explanation:

      A refractory period follows each action potential. The absolute refractory time and the relative refractory period are two divisions of refractory periods. Because the sodium channels seal after an AP, they enter an inactive state during which they cannot be reopened regardless of membrane potential, this time occurs.The sodium channels slowly come out of inactivation during the relative refractory period that follows. During this time, a stronger stimulus than that required to initiate an action potential can excite the cell. The strength of the stimulus required early in the relative refractory period is relatively high, and it steadily decreases as more sodium channels recover from the inactivation of the refractory period.Nodes of Ranvier are periodic holes in a myelinate axon when there is no myelin and the axonal membrane is exposed. There are no gated ion channels in the portion of the axon covered by the myelin sheath, but there is a high density of ion channels in the Nodes of Ranvier. Action potentials can only occur at the nodes as a result of this.

    • This question is part of the following fields:

      • Basic Cellular Physiology
      • Physiology
      30.3
      Seconds
  • Question 4 - Which of the following is NOT a pharmacological effect of beta-blockers: ...

    Correct

    • Which of the following is NOT a pharmacological effect of beta-blockers:

      Your Answer: Reduced AV conduction time

      Explanation:

      Effects of beta-blockers:Cardiovascular system: Reduce blood pressureReduce heart rate, contractility and cardiac outputIncrease AV conduction time, refractoriness and suppress automaticityEye:Reduce intraocular pressureRespiratory system:Cause bronchoconstriction

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      12.7
      Seconds
  • Question 5 - Which of the following states that the total pressure exerted by a mixture...

    Correct

    • Which of the following states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each of the gases in the mixture:

      Your Answer: Dalton's law

      Explanation:

      Dalton’s law states that when two or more gases, which do not react chemically, are present in the same container, the total pressure is the sum of the partial pressures of each gas.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      9.6
      Seconds
  • Question 6 - Pressure across the wall of a flexible tube (the transmural pressure) increases wall...

    Incorrect

    • Pressure across the wall of a flexible tube (the transmural pressure) increases wall tension and extends it.Which law best describes transmural pressure?

      Your Answer: Starling’s law

      Correct Answer: Laplace’s law

      Explanation:

      The transmural pressure (pressure across the wall of a flexible tube) can be described by Laplace’s law which states that:Transmural pressure = (Tw) / rWhere:T = Wall tensionw = Wall thicknessr = The radiusA small bubble with the same wall tension as a larger bubble will contain higher pressure and will collapse into the larger bubble if the two meet and join.Fick’s law describes the rate of diffusion in a solutionPoiseuille’s law is used to calculate volume of flow rate in laminar flowDarcy’s law describes the flow of a fluid through a porous medium.Starling’s law describes cardiac haemodynamics as it relates to myocyte contractility and stretch.

    • This question is part of the following fields:

      • Basic Cellular Physiology
      • Physiology
      9.9
      Seconds
  • Question 7 - As a response to low blood pressure, the baroreceptor reflex will facilitate vasoconstriction...

    Correct

    • As a response to low blood pressure, the baroreceptor reflex will facilitate vasoconstriction by activating which receptor?

      Your Answer: Alpha1

      Explanation:

      The rate of baroreceptor firing slows down when blood pressure falls too low. This causes an increase in sympathetic stimulation of the heart, resulting in an increase in cardiac output. It also causes vasoconstriction by activating alpha 1 receptors in smooth muscle, which causes sympathetic stimulation of peripheral vessels. Alpha2 receptors can be found in both the brain and the peripheral nervous system. They control sympathetic outflow in the brain stem. Beta1 receptors, which are found on the cell membrane of cardiac muscle cells, stimulate heart rate and myocardial contractility. The smooth muscle cell membrane contains beta2 receptors, which promote smooth muscle relaxation in the lungs causing bronchodilation, GI tract, and peripheral blood vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      12.8
      Seconds
  • Question 8 - On her most recent blood tests, a 55 year-old female with a history of hypertension...

    Incorrect

    • On her most recent blood tests, a 55 year-old female with a history of hypertension was discovered to be hypokalaemic. She  is diagnosed with primary hyperaldosteronism.Which of the following is a direct action of aldosterone?

      Your Answer: Reabsorption of Na + into the proximal convoluted tubule

      Correct Answer: Secretion of H + into the distal convoluted tubule

      Explanation:

      Aldosterone is a steroid hormone produced in the adrenal cortex’s zona glomerulosa. It is the most important mineralocorticoid hormone in the control of blood pressure. It does so primarily by promoting the synthesis of Na+/K+ATPases and the insertion of more Na+/K+ATPases into the basolateral membrane of the nephron’s distal tubules and collecting ducts, as well as stimulating apical sodium and potassium channel activity, resulting in increased sodium reabsorption and potassium secretion. This results in sodium conservation, potassium secretion, water retention, and a rise in blood volume and blood pressure.Aldosterone is produced in response to the following stimuli:Angiotensin II levels have risen.Potassium levels have increased.ACTH levels have risen.Aldosterone’s principal actions are as follows:Na+ reabsorption from the convoluted tubule’s distal endWater resorption from the distal convoluted tubule (followed by Na+)Cl is reabsorbed from the distal convoluted tubule.K+ secretion into the convoluted distal tubule’s H+ secretion into the convoluted distal tubule’s 

    • This question is part of the following fields:

      • Physiology
      • Renal Physiology
      11.9
      Seconds
  • Question 9 - A 50-year-old man presents with headaches, lethargy, hypertension, and electrolyte disturbance. A diagnosis...

    Incorrect

    • A 50-year-old man presents with headaches, lethargy, hypertension, and electrolyte disturbance. A diagnosis of primary hyperaldosteronism is made.Which biochemical pictures would best support this diagnosis?

      Your Answer: Hypokalaemic metabolic acidosis

      Correct Answer: Hypokalaemic metabolic alkalosis

      Explanation:

      When there are excessive levels of aldosterone outside of the renin-angiotensin axis, primary hyperaldosteronism occurs. High renin levels will lead to secondary hyperaldosteronism. The classical presentation of hyperaldosteronism when symptoms are present include:HypokalaemiaMetabolic alkalosisHypertensionNormal or slightly raised sodium levels

    • This question is part of the following fields:

      • Endocrine Physiology
      • Physiology
      16
      Seconds
  • Question 10 - Bile acids are essential for the digestion and absorption of which of the...

    Correct

    • Bile acids are essential for the digestion and absorption of which of the following:

      Your Answer: Lipids and fat-soluble vitamins

      Explanation:

      Bile acids are synthesised from cholesterol by hepatocyte and excreted into bile. Bile acids are essential for lipid digestion and absorption. Of the bile acids excreted into the intestine, about 95% are reabsorbed into the portal circulation by active transport mechanisms in the distal ileum and recycled by the liver. Many of the bile salts are reabsorbed unaltered, some are converted by intestinal bacteria into secondary bile acids (deoxycholic acid and lithocholic acid) and then reabsorbed and a small proportion escapes reabsorption and is excreted in the faeces.

    • This question is part of the following fields:

      • Gastrointestinal
      • Physiology
      6.9
      Seconds
  • Question 11 - Angiotensin II is part of the RAAS system. One of its effects is...

    Incorrect

    • Angiotensin II is part of the RAAS system. One of its effects is the constriction of efferent arterioles. Which of the following best describes the effect of angiotensin II- mediated constriction of efferent arterioles?

      Your Answer:

      Correct Answer: Decreased renal plasma flow, increased filtration fraction, increased GFR

      Explanation:

      The Renin-Angiotensin-Aldosterone System (RAAS) is a hormone system composed of renin, angiotensin, and aldosterone. Those hormones are essential for the regulation of blood pressure and fluid balance. Cases of hypotension, sympathetic stimulation, or hyponatremia can activate the Renin-angiotensin-aldosterone system (RAAS). The following process will then increase the blood volume and blood pressure as a response. When renin is released it will convert the circulating angiotensinogen to angiotensin I. The ACE or angiotensin-converting enzyme will then catalyst its conversion to angiotensin II, which is a potent vasoconstrictor. Angiotensin II can constrict the vascular smooth muscles and the efferent arteriole of the glomerulus. The efferent arteriole is a blood vessel that delivers blood away from the capillaries of the kidney. The angiotensin II-mediated constriction of efferent arterioles increases GFR, reduces renal blood flow and peritubular capillary hydrostatic pressure, and increases peritubular colloid osmotic pressure, as a response to its action of increasing the filtration fraction.

    • This question is part of the following fields:

      • Physiology
      • Renal Physiology
      0
      Seconds
  • Question 12 - Depolarisation of a neuron begins with which of the following: ...

    Incorrect

    • Depolarisation of a neuron begins with which of the following:

      Your Answer:

      Correct Answer: Opening of ligand-gated Na + channels

      Explanation:

      Action potentials are initiated in nerves by activation of ligand-gated Na+channels by neurotransmitters. Opening of these Na+channels results in a small influx of sodium and depolarisation of the negative resting membrane potential (-70 mV). If the stimulus is sufficiently strong, the resting membrane depolarises enough to reach threshold potential (generally around -55 mV), at which point an action potential can occur. Voltage-gated Na+channels open, causing further depolarisation and activating more voltage-gated Na+channels and there is a sudden and massive sodium influx, driving the cell membrane potential to about +40 mV.

    • This question is part of the following fields:

      • Basic Cellular
      • Physiology
      0
      Seconds
  • Question 13 - Antispasmodic drugs are primarily indicated in which of the following conditions: ...

    Incorrect

    • Antispasmodic drugs are primarily indicated in which of the following conditions:

      Your Answer:

      Correct Answer: Irritable bowel syndrome

      Explanation:

      Antispasmodics, such as antimuscarinics, may be used in the management of irritable bowel syndrome. Other antispasmodics used include direct-acting smooth muscle relaxants such as mebeverine, alverine, and peppermint oil. Antispasmodics are contraindicated in bowel obstruction and severe inflammatory bowel disease. Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects. Antimuscarinics are contraindicated in urinary retention.

    • This question is part of the following fields:

      • Gastrointestinal
      • Pharmacology
      0
      Seconds
  • Question 14 - In adult basic life support, chest compressions should be performed at which of...

    Incorrect

    • In adult basic life support, chest compressions should be performed at which of the following rates:

      Your Answer:

      Correct Answer: 100 - 120 per minute

      Explanation:

      Chest compressions should be performed at a rate of 100 – 120 per minute.

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      0
      Seconds
  • Question 15 - Regarding the partial pressure of gases, which of the following statements is INCORRECT:...

    Incorrect

    • Regarding the partial pressure of gases, which of the following statements is INCORRECT:

      Your Answer:

      Correct Answer: At high altitude, the oxygen fraction is reduced.

      Explanation:

      At altitude, the oxygen fraction is unaltered but the barometric pressure and thus partial pressure of oxygen is reduced.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      0
      Seconds
  • Question 16 - Which of the following is NOT an adverse effect associated with warfarin therapy:...

    Incorrect

    • Which of the following is NOT an adverse effect associated with warfarin therapy:

      Your Answer:

      Correct Answer: Neutropenia

      Explanation:

      Adverse effects of warfarin:The most common adverse effect of warfarin is bleedingOther common adverse effects of warfarin include nausea, vomiting, diarrhoea, jaundice, hepatic dysfunction, pancreatitis, pyrexia, alopecia, purpura, and rashSkin necrosis is a rare but serious adverse effect of warfarin; treatment with warfarin should be stopped if warfarin related skin necrosis is suspectedCalciphylaxis is a rare, but a very serious condition that causes vascular calcification and cutaneous necrosis

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      0
      Seconds
  • Question 17 - The following are all important buffers of H+EXCEPT for: ...

    Incorrect

    • The following are all important buffers of H+EXCEPT for:

      Your Answer:

      Correct Answer: Calcium

      Explanation:

      Buffers are weak acids or bases that can donate or accept H+ions respectively and therefore resist changes in pH. Buffering does not alter the body’s overall H+load, ultimately the body must get rid of H+by renal excretion if the buffering capacity of the body is not to be exceeded and a dangerous pH reached. Bicarbonate and carbonic acid (formed by the combination of CO2 with water, potentiated by carbonic anhydrase) are the most important buffer pair in the body, although haemoglobin provides about 20% of buffering in the blood, and phosphate and proteins provide intracellular buffering. Buffers in urine, largely phosphate, allow the excretion of large quantities of H+.

    • This question is part of the following fields:

      • Physiology
      • Renal
      0
      Seconds
  • Question 18 - A 39-year-old woman is feeling unwell one week after a parathyroid surgery.Which of...

    Incorrect

    • A 39-year-old woman is feeling unwell one week after a parathyroid surgery.Which of the following stimulates release of parathyroid hormone (PTH)?

      Your Answer:

      Correct Answer: Increased plasma phosphate concentration

      Explanation:

      PTH is synthesised and released from the chief cells of the four parathyroid glands located behind the thyroid gland.It is a polypeptide containing 84 amino acids and it controls free calcium in the body.The following stimuli causes release of PTH:Increased plasma phosphate concentrationDecreased plasma calcium concentrationPTH release is inhibited by:Normal or increased plasma calcium concentrationHypomagnesaemiaThe main actions of PTH are:Increases plasma calcium concentrationDecreases plasma phosphate concentrationIncreases osteoclastic activity (increasing calcium and phosphate resorption from bone)Increases renal tubular reabsorption of calciumDecreases renal phosphate reabsorptionIncreases renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol (via stimulation of 1-alpha hydroxylase)Increases calcium and phosphate absorption in the small intestine (indirectly via increased 1,25-dihydroxycholecalciferol)

    • This question is part of the following fields:

      • Endocrine Physiology
      • Physiology
      0
      Seconds
  • Question 19 - On review of a patient's serum and urine osmolality test result, you note...

    Incorrect

    • On review of a patient's serum and urine osmolality test result, you note that both osmolarities are decreased. There urine osmolality does not increase with fluid ingestion.What is the most likely cause?

      Your Answer:

      Correct Answer: Hyponatraemia

      Explanation:

      As part of the investigation of hyponatraemia, serum osmolality is commonly requested in combination with urine osmolality to aid diagnosis.When: Serum osmolality is decreased and urine osmolality is decreased with no intake of fluid, the causes areHyponatraemiaOverhydrationAdrenocortical insufficiencySodium loss (diuretic or a low-salt diet)Serum osmolality is normal or increased and urine osmolality is increased the causes include:DehydrationHyperkalaemiaHyperglycaemiaHyponatremiaMannitol therapyDiabetes mellitusAlcohol ingestionCongestive heart failureRenal disease and uraemiaSerum osmolality is normal or increased and urine osmolality is decreased the usual cause is diabetes insipidusSerum osmolality is decreased and urine osmolality is increased the usual cause is syndrome of inappropriate antidiuresis (SIAD)

    • This question is part of the following fields:

      • Basic Cellular Physiology
      • Physiology
      0
      Seconds
  • Question 20 - All of the following are indications for beta-blockers EXCEPT for: ...

    Incorrect

    • All of the following are indications for beta-blockers EXCEPT for:

      Your Answer:

      Correct Answer: Prinzmetal's angina

      Explanation:

      Beta-blockers are contraindicated in Prinzmetal’s angina.Beta-blockers may be indicated in:HypertensionPheochromocytoma (only with an alpha-blocker)AnginaSecondary prevention after ACSArrhythmias including atrial fibrillationHeart failureThyrotoxicosisAnxietyProphylaxis of migraineEssential tremorGlaucoma

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      0
      Seconds
  • Question 21 - For a tachyarrhythmia caused by hypovolaemic shock, which of the following is the...

    Incorrect

    • For a tachyarrhythmia caused by hypovolaemic shock, which of the following is the first-line treatment:

      Your Answer:

      Correct Answer: Synchronised DC shock

      Explanation:

      If there are any adverse symptoms, immediate cardioversion with synchronized DC shock is recommended. If cardioversion fails to stop the arrhythmia and the symptoms persist, amiodarone 300 mg IV over 10–20 minutes should be administered before attempting another cardioversion. The loading dosage of amiodarone is followed by a 24-hour infusion of 900 mg administered into a large vein.

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      0
      Seconds
  • Question 22 - Regarding carbon dioxide transport in the blood, which of the following statements is...

    Incorrect

    • Regarding carbon dioxide transport in the blood, which of the following statements is CORRECT:

      Your Answer:

      Correct Answer: Deoxygenated haemoglobin acts as a buffer for H+ ions.

      Explanation:

      CO2generated in the tissues and water combine to form carbonic acid which readily dissociates to form HCO3-and H+. The first part of this reaction is very slow in plasma, but is accelerated dramatically by the enzyme carbonic anhydrase present in red blood cells. Bicarbonate is therefore formed preferentially in red cells, from which it freely diffuses down its concentration gradient into plasma where it is transported to the lungs. The red cell membrane is impermeable to H+ions which remain in the cell. To maintain electroneutrality, Cl-ions diffuse into the cell to replace HCO3-, an effect known as the chloride shift. Deoxygenated haemoglobin acts as a buffer for H+, allowing the reaction to continue.

    • This question is part of the following fields:

      • Physiology
      • Respiratory
      0
      Seconds
  • Question 23 - What is the main mechanism of action of dobutamine as an inotropic sympathomimetic:...

    Incorrect

    • What is the main mechanism of action of dobutamine as an inotropic sympathomimetic:

      Your Answer:

      Correct Answer: Beta1-receptor agonist

      Explanation:

      Dobutamine directly stimulates the beta1-adrenergic receptors in the heart and increases contractility and cardiac output with little effect on the rate. In addition action on beta2-receptors causes vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Pharmacology
      0
      Seconds
  • Question 24 - The renin-angiotensin-aldosterone system (RAAS) controls blood pressure and fluid balance.Which of the following...

    Incorrect

    • The renin-angiotensin-aldosterone system (RAAS) controls blood pressure and fluid balance.Which of the following sites produces the most angiotensinogen? 

      Your Answer:

      Correct Answer: The liver

      Explanation:

      Angiotensinogen is an alpha-2-globulin generated predominantly by the liver and released into the blood. Renin, which cleaves the peptide link between the leucine and valine residues on angiotensinogen, converts it to angiotensin I.Angiotensinogen levels in the blood are raised by:Corticosteroid levels have risen.Thyroid hormone levels have risen.Oestrogen levels have risen.Angiotensin II levels have risen.

    • This question is part of the following fields:

      • Physiology
      • Renal Physiology
      0
      Seconds
  • Question 25 - Which statement regarding skeletal muscle is true? ...

    Incorrect

    • Which statement regarding skeletal muscle is true?

      Your Answer:

      Correct Answer: Myosin is the major constituent of the thick filament

      Explanation:

      Myosin is the major constituent of the thick filament. Actin is the major constituent of the THIN filament. Thin filaments consist of actin, tropomyosin and troponin in the ratio 7:1:1.

    • This question is part of the following fields:

      • Basic Cellular Physiology
      • Physiology
      0
      Seconds
  • Question 26 - Glucagon may be used as an antidote for overdose with which of the...

    Incorrect

    • Glucagon may be used as an antidote for overdose with which of the following:

      Your Answer:

      Correct Answer: Beta blockers

      Explanation:

      Glucagon is a peptide hormone that is produced and secreted by alpha cells of the islets of Langerhans, which are located in the endocrine portion of the pancreas. The main physiological role of glucagon is to stimulate hepatic glucose output, thereby leading to increases in glycaemia. It provides the major counter-regulatory mechanism to insulin in maintaining glucose homeostasis.Hypoglycaemia is the principal stimulus for the secretion of glucagon but may also be used as an antidote in beta-blocker overdose and in anaphylaxis in patients on beta-blockers that fail to respond to adrenaline. Glucagon then causes:GlycogenolysisGluconeogenesisLipolysis in adipose tissueThe secretion of glucagon is also stimulated by:AdrenalineCholecystokininArginineAlanineAcetylcholineThe secretion of glucagon is inhibited by:InsulinSomatostatinIncreased free fatty acidsIncreased urea productionGlycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released by this process is used to form ATP and NADH. Glycolysis is inhibited by glucagon, and glycolysis and gluconeogenesis are reciprocally regulated so that when one cell pathway is activated, the other is inactive and vice versa.Glucagon has a minor effect of enhancing lipolysis in adipose tissue. Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into glycerol and free fatty acids. It makes fatty acids available for oxidation.

    • This question is part of the following fields:

      • Endocrine
      • Pharmacology
      0
      Seconds
  • Question 27 - A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle...

    Incorrect

    • A 54-year-old woman has been visiting her GP with symptoms of tiredness, muscle weakness and headaches. She is known to be hypertensive and takes amlodipine to control this. Her blood results today show that her potassium level is low at 3.0 mmol/L, and her sodium level is slightly elevated at 146 mmol/L.Which of the following is the SINGLE most appropriate INITIAL investigation?

      Your Answer:

      Correct Answer: Plasma renin and aldosterone levels

      Explanation:

      Primary hyperaldosteronism occurs when there are excessive levels of aldosterone independent of the renin-angiotensin axis. Secondary hyperaldosteronism occurs due to high renin levels.The causes of primary hyperaldosteronism include:Adrenal adenoma (Conn’s syndrome) – the most common cause of hyperaldosteronism (,80% of all cases). These are usually unilateral and solitary and are more common in women.Adrenal hyperplasia – this accounts for ,15% of all cases. Usually, bilateral adrenal hyperplasia (BAH) but can be unilateral rarely. More common in men than women.Adrenal cancer – a rare diagnosis but essential not to missFamilial aldosteronism – a rare group of inherited conditions affecting the adrenal glandsThe causes of secondary hyperaldosteronism include:Drugs – diureticsObstructive renal artery disease – renal artery stenosis and atheromaRenal vasoconstriction – occurs in accelerated hypertensionOedematous disorders – heart failure, cirrhosis and nephrotic syndromePatients are often asymptomatic. When clinical features are present, the classically described presentation of hyperaldosteronism is with:HypertensionHypokalaemiaMetabolic alkalosisSodium levels can be normal or slightly raisedOther, less common, clinical features include:LethargyHeadachesMuscle weakness (from persistent hypokalaemia)Polyuria and polydipsiaIntermittent paraesthesiaTetany and paralysis (rare)Often the earliest sign of hyperaldosteronism is from aberrant urea and electrolytes showing hypokalaemia and mild hypernatraemia. If the patient is taking diuretics, and the diagnosis is suspected, these should be repeated after the patient has taken off diuretics.If the diagnosis is suspected, plasma renin and aldosterone levels should be checked. Low renin and high aldosterone levels (with a raised aldosterone: renin ratio) is suggestive of primary aldosteronism.If the renin: aldosterone ratio is high, then the effect of posture on renin, aldosterone and cortisol can be investigated to provide further information about the underlying cause of primary hyperaldosteronism. Levels should be measured lying at 9 am and standing at noon:If aldosterone and cortisol levels fall on standing, this is suggestive of an ACTH dependent cause, e.g. adrenal adenoma (Conn’s syndrome)If aldosterone levels rise and cortisol levels fall on standing, this is suggestive of an angiotensin-II dependent cause, e.g. BAHOther investigations that can help to distinguish between an adrenal adenoma and adrenal hyperplasia include:CT scanMRI scanSelective adrenal venous sampling

    • This question is part of the following fields:

      • Endocrine Physiology
      • Physiology
      0
      Seconds
  • Question 28 - When the pulmonary artery is completely blocked, what is the ventilation over perfusion...

    Incorrect

    • When the pulmonary artery is completely blocked, what is the ventilation over perfusion ratio for the area that it supplies?

      Your Answer:

      Correct Answer: Infinity

      Explanation:

      The ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the matching ventilation and perfusion. A pulmonary artery carries deoxygenated blood from the right side of the heart to the lungs. When a large pulmonary embolus completed blocked a pulmonary artery the alveoli were ventilated but not perfused at all, then the V/Q ratio would be infinity.

    • This question is part of the following fields:

      • Physiology
      • Respiratory Physiology
      0
      Seconds
  • Question 29 - A 58-year-old woman presents with symptoms of increase in weight, proximal muscular weakening...

    Incorrect

    • A 58-year-old woman presents with symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that she has a full, plethoric aspect to her face, as well as significant supraclavicular fat pads, when you examine her. She has previously been diagnosed with Cushing's syndrome.Which of the following biochemical profiles best supports this diagnosis?

      Your Answer:

      Correct Answer: Hypokalaemic metabolic alkalosis

      Explanation:

      Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.A typical biochemical profile can help establish a diagnosis of Cushing’s syndrome. The following are the primary characteristics:HypokalaemiaAlkalosis metabolique

    • This question is part of the following fields:

      • Endocrine Physiology
      • Physiology
      0
      Seconds
  • Question 30 - A 59-year-old otherwise well woman presents with a history of polydipsia and polyuria....

    Incorrect

    • A 59-year-old otherwise well woman presents with a history of polydipsia and polyuria. There is a past history of kidney stones, and blood tests done reveal the following: Na: 147 mmol/L (135-147 mmol/L) K: 4.0 mmol/L (3.5-5.5 mmol/L) Urea: 7.3 mmol/L (2.0-6.6 mmol/L) Creatinine: 126 mmol/L (75-125 mmol/L) Fasting blood glucose: 5.0 mmol/L (3.4-5.5 mmol/L) Corrected calcium: 3.21 mmol/L (2.05-2.60 mmol/L) Phosphate: 0.70 mmol/L (0.8-1.4 mmol/L) Parathyroid hormone: 189 ng/L (10-60 ng/L)The most likely diagnosis is?

      Your Answer:

      Correct Answer: Primary hyperparathyroidism

      Explanation:

      ​Primary hyperparathyroidism the commonest cause of hypercalcaemia. It is commonest in women aged 50 to 60.The commonest cause of primary hyperparathyroidism is a solitary adenoma of the parathyroid gland (approximately 85% of cases). Primary hyperparathyroidism may present with features of hypercalcaemia such as polyuria, polydipsia, renal stones, bone and joint pain, constipation, and psychiatric disorders.In primary Hyperparathyroidism:PTH is elevatedCalcium is elevatedPhosphate is loweredIn secondary Hyperparathyroidism:PTH is elevatedCalcium is low or low-normalPhosphate is raised in CRFIn tertiary Hyperparathyroidism:PTH is elevatedCalcium is elevatedPhosphate is lowered in CRF

    • This question is part of the following fields:

      • Endocrine Physiology
      • Physiology
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