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Question 1
Correct
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The amount of a substance taken up by an organ (or whole body) per unit time is = (the arterial level - the venous level) * the blood flow. This statement describes?
Your Answer: The Fick principle
Explanation:The essence of the Fick principle is that blood flow to an organ can be calculated using a marker substance if the following information is known:- Amount of marker substance taken up by the organ per unit time- Concentration of marker substance in arterial blood supplying the organ- Concentration of marker substance in venous blood leaving the organ
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 2
Incorrect
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Which of the following regulates the calcium release channels?
Your Answer: The calcium concentration
Correct Answer: Calstabin 2
Explanation:Ca2+ is released from the SR through a Ca2+ release channel, a cardiac isoform of the ryanodine receptor (RyR2), which controls intracytoplasmic [Ca2+] and, as in vascular smooth-muscle cells, leads to the local changes in intracellular [Ca2+] called calcium sparks. A number of regulatory proteins, including calstabin 2, inhibit RyR2 and, thereby, the release of Ca2+ from the SR.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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Excitation-contraction coupling in cardiac muscle involves all of the following except:
Your Answer: Binding of Ca2+ to calmodulin
Explanation:In the excitation contraction coupling model, an action potential is transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors. These are voltage gates calcium channels. Calcium binds to calmodulin during contraction of the smooth muscle and not the cardiac muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 4
Correct
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The principle by which the energy of contraction is proportional to the initial length of cardiac muscle fiber is known as:
Your Answer: Starling’s law
Explanation:The Frank starling relationship describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increase venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and increased development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relation is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Correct
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The following products of the vascular endothelium produce vasodilation except:
Your Answer: Endothelin
Explanation:Endothelin: This is incorrect in the context of vasodilation. Endothelin is actually a potent vasoconstrictor produced by the endothelium, leading to the narrowing of blood vessels and increased blood pressure.
Nitrous oxide (Nitric oxide): This is correct for vasodilation. Nitric oxide is a powerful vasodilator produced by the endothelium, which helps relax and widen blood vessels.
Prostacyclin: This is correct for vasodilation. Prostacyclin (PGI2) is a vasodilator and inhibits platelet aggregation, helping to maintain blood flow and reduce clot formation.
Endothelial-derived hyperpolarizing factor (EDHF): This is correct for vasodilation. EDHF causes vasodilation by hyperpolarizing the smooth muscle cells of blood vessels.
Vascular endothelial growth factor (VEGF): This is correct for vasodilation. VEGF primarily promotes the growth of new blood vessels but also has vasodilatory effects through nitric oxide production.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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According to Starling's law of the heart:
Your Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Correct
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In a normal heart rate at rest, the left ventricular end-diastolic volume is ….
Your Answer: 100-130 ml
Explanation:In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right and/or left ventricle at end load or filling in (diastole) or the amount of blood in the ventricles just before systole. Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to contraction (systole). End-diastolic volume: Right = 144 mL(± 23mL) & Left = 142 mL (± 21 mL).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 8
Incorrect
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Which of the following normally has a slow depolarizing “prepotential”?
Your Answer: Atrial muscle cells
Correct Answer: Sinoatrial node
Explanation:There are 2 main types of action potentials (AP) in the heart, the slow response and the fast response:The slow response is initiated by the slow calcium-sodium channels, found in the SA node (which is the natural pacemaker of the heart) and the conduction fibers of the AV node.The fast response occurs in the atrial and ventricles muscle cells and the purkinje fibers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Incorrect
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The following is true of the sinus node:
Your Answer: It is made up of specialised neural cells
Correct Answer: It generates impulses automatically & at a quicker rate than other cardiac cells
Explanation:The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Correct
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Question 11
Incorrect
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Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme?
Your Answer: Adenylate cyclase
Correct Answer: Guanylyl cyclase
Explanation:Impaired production or excess catabolism of NO impairs this endothelium-dependent vasodilator function and may contribute to excessive vasoconstriction under various pathological situations.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Correct
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Which of the following has the shortest duration:
Your Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?
Your Answer: Aortic regurgitation
Correct Answer: Aortic aneurysm
Explanation:Marfan syndrome (MFS) is a genetic disorder of connective tissue. The degree to which people are affected varies. People with Marfan’s tend to be tall, and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Correct
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Most of the venous blood returns to the heart through the:
Your Answer: Coronary sinus and anterior cardiac veins
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins which drain into the right atrium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Incorrect
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Which of the following antiarrhythmic drugs may be used in the treatment of long QT syndrome?
Your Answer: Amiodarone
Correct Answer: Atenolol
Explanation:Beta-blockers are the mainstay of treatment in long QT syndrome. Implantable cardioverter-defibrillators are the most effective treatment in genotypes with a high risk of recurrence.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 16
Correct
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The initial rapid depolarization in the action potential of cardiac muscle cells is due to:
Your Answer: Opening of voltage-gated Na+ channels
Explanation:The initial depolarization of the action potential in a cardiac muscle cell is due to the sodium current generated by opening of the voltage gated sodium channels leading to an influx of sodium ions into the cell and raising the membrane potential towards threshold.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Correct
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Question 18
Correct
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Question 19
Correct
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Which one of the following have not been shown to improve mortality in patients with chronic heart failure?
Your Answer: Furosemide
Explanation:A number of drugs have been shown to improve mortality in patients with chronic heart failure:
- ACE inhibitors (SAVE, SOLVD, CONSENSUS)
- spironolactone (RALES)
- beta-blockers (CIBIS)
- hydralazine with nitrates (VHEFT-1)
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Correct
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Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 21
Correct
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What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?
Your Answer: Shifts the diastolic pressure curve upward and leftward
Explanation:Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Incorrect
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Question 23
Correct
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Question 24
Correct
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The triangle with the heart at its centre, using limb leads is called:
Your Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Incorrect
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The major factor in controlling coronary artery blood flow is considered to be?
Your Answer: Parasympathetic input
Correct Answer: Metabolites of oxygen consumption
Explanation:There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Correct
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Which of the following occurs during a Valsalva manoeuvre?
Your Answer: An initial rise in blood pressure
Explanation:The Valsalva maneuver involves forced expiration against a closed glottis. It has several phases, each affecting the cardiovascular system differently:
- Phase I: During the initial forced expiration against the closed glottis, there is a transient rise in intrathoracic pressure, which compresses the thoracic aorta and causes a brief increase in blood pressure.
- Phase II: Continued straining leads to decreased venous return to the heart, reducing cardiac output and causing a drop in blood pressure. This phase is characterized by a compensatory increase in heart rate.
- Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
- Phase IV: Blood pressure then rises rapidly as venous return to the heart is restored, leading to increased cardiac output. This is often followed by a reflex bradycardia (slow heart rate).
Given these phases, the most accurate statement about what occurs during the Valsalva maneuver is the initial rise in blood pressure (Phase I).
Other options explained:
- Forced inspiration against a closed glottis: Incorrect. The Valsalva maneuver involves forced expiration, not inspiration, against a closed glottis.
- Low intrathoracic pressures throughout: Incorrect. The Valsalva maneuver involves high intrathoracic pressures due to forced expiration.
- Disruption of autonomic function: Incorrect. The Valsalva maneuver affects autonomic function but does not disrupt it. Instead, it triggers autonomic responses to changes in blood pressure and heart rate.
- No change: Incorrect. The Valsalva maneuver causes significant changes in blood pressure and heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 27
Incorrect
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The V wave in the jugular pulse is caused by:
Your Answer: Ventricular filling
Correct Answer: Atrial filling
Explanation:The v wave reflects the passive increase in pressure and volume of the right atrium as it fills in late systole and early diastole.
The jugular vein pulsations usually have two elevations and two troughs. The first elevation (a wave) corresponds to the slight rise in atrial pressure resulting from atrial contraction. The first descent (x descent) reflects a fall in atrial pressure that starts with atrial relaxation. The second elevation (v wave) corresponds to ventricular systole when blood is entering the right atrium from the vena cavae while the tricuspid valve is closed. Finally, the second descent (y descent) reflects falling right atrial pressure as the tricuspid valve opens and blood drains from the atrium into the ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 28
Incorrect
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Concerning S3, which of the following statements is INCORRECT?
Your Answer: Occurs during ventricular rapid filling phase
Correct Answer: Coincide with atrial contraction
Explanation:A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 29
Incorrect
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Where are the baroreceptors of the great arteries located?
Your Answer: In the smooth muscle
Correct Answer: In the adventitia
Explanation:Arterial baroreceptors are located in the aortic arch and carotid sinuses, and are formed by small nerve endings present in the adventitia of these vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Correct
SESSION STATS - PERFORMANCE PER SPECIALTY
