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Question 1
Correct
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Myocardium requires more oxygen to expel blood in:
Your Answer: A stenotic aortic valve
Explanation:In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.
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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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Sinus bradycardia may be caused by disease of which of the following:
Your Answer: Left coronary artery
Correct Answer: Right coronary artery
Explanation:Disease of the right coronary artery may cause sinus bradycardia and AV nodal block.
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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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Question 4
Incorrect
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Which of the following factors serve to decrease cardiac output?
Your Answer: Increased ambient temperature
Correct Answer: Standing from a lying position
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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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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Although variable, branches of which artery most often supply the SA and AV nodes?
Your Answer: Right coronary artery
Explanation:The RCA (right coronary artery) supplies the SA and the AV nodes along with the postero-basal wall of the left ventricle, posterior one third of the inferior vena cava, right ventricle and the posteromedial papillary muscle in the left ventricle.
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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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Question 7
Correct
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Which ion channel does not contribute to the myocardial action potential?
Your Answer: Chloride channel
Explanation:The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 8
Correct
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What is a characteristic findings on ECG in hyperkalaemia?
Your Answer: Tall, tented T waves
Explanation:Hyperkalaemia leads to:
– Prolonged PR interval
– Small P waves
– Tall, tented T waves
– Widened QRS complexes and eventually asystole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Correct
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Which of the following affects the magnitude of the action potential?
Your Answer: Changes in the external Na+ concentration
Explanation:The magnitude of the action potential is determined by the sodium current. Increase in external sodium will result in increased influx of sodium and hence generation of a stronger action potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Incorrect
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In Jugular vein pressure the “a” wave represents?
Your Answer: Atrial relaxation
Correct Answer: Atrial systole
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described: The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 11
Correct
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Coronary arteries fill up during
Your Answer: Diastole
Explanation:During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high ventricular pressures. This compression results in momentary retrograde blood flow (i.e., blood flows backward toward the aorta) which further inhibits perfusion of myocardium during systole. However, the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain open. Because of this, blood flow in the sub endocardium stops during ventricular contraction. As a result, most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are open and under lower pressure.
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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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Question 13
Incorrect
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Vasodilatation in skeletal muscle can be caused by:
Your Answer: Thromboxane a2
Correct Answer: Sympathetic cholinergic nerves
Explanation:In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.
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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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All valves are closed in which phase of the cardiac cycle?
Your Answer: Isovolumetric relaxation
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
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 16
Correct
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What is the isolated effect of B2 stimulation on the coronaries?
Your Answer: Vasodilatation
Explanation:Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.
Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.
Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.
Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.
Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Incorrect
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Which of the following is NOT associated with the development of aortic regurgitation?
Your Answer: Ankylosing spondylitis
Correct Answer: Dilated cardiomyopathy
Explanation:Aortic insufficiency, is often due to the aortic root dilation, which is idiopathic in over 80% of cases, but otherwise may result from aging, syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Bechet’s disease, reactive arthritis and systemic hypertension. Additionally, aortic insufficiency has been linked to the use of some medications and other potential causes that affect the valve directly including Marfan’s syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, and systemic lupus erythematosus. In acute cases of aortic insufficiency, the main causes are infective endocarditis, aortic dissection or trauma. Dilated cardiomyopathy is associated with the development of mitral regurgitation, not aortic regurgitation
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 18
Correct
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The branche(s) of the left coronary artery include:
Your Answer: Left circumflex artery & anterior interventricular artery
Explanation:The left main coronary divides into branches:
1. The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.
2. The circumflex artery branches off the left coronary artery and encircles the heart muscle.
The anterior interventricular artery is otherwise known as the anterior descending branch. The posterior descending artery comes from Right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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The process by which depolarization of the muscle fiber initiates contraction is called?
Your Answer: Excitation – contraction coupling
Correct Answer: Action potential
Explanation:This process is known as an action potential. Upon generation of an action potential when depolarization reaches threshold, it spreads throughout the muscle fiber, resulting in generation of an excitation-contraction coupling leading to contraction of the muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Incorrect
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Which of the following is true with AV nodal delay?
Your Answer: The delay is about 0.01s
Correct Answer: Shortened by sympathetic stimulation
Explanation:AV nodal delay Is about 0.1s before the action potential spreads to the ventricles. It is shortened by stimulation of the sympathetic nervous system and lengthened by stimulation of the parasympathetic system.
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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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Xanthines such as caffeine and theophylline are positively inotropic due to:
Your Answer: Inhibition of cAMP breakdown
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contractions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Correct
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Regarding blood supply to the heart;
Your Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Correct
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Question 24
Correct
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Question 25
Incorrect
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All of the following are consistent with the indicator dilution method except---
Your Answer: The cardiac output is equal to the amount of indicator injected divided by its average concentration in arterial blood after a single circulation though the heart
Correct Answer: In thermodilution, the indicator used is warm saline
Explanation:In thermodilution, the indicator used is cold saline.
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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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Cholinergic vagal supply to the SA and AV nodes results in slowing of the heart rate via:
Your Answer: M2 muscarinic receptors
Explanation:M2 muscarinic receptors are the receptors for the parasympathetic system to the SA and the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 27
Correct
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In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should be made at:
Your Answer: 200 J
Explanation:Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. If the patient is in Ventricular tachycardia (VT) or ventricular fibrillation (VF) on the monitor, immediately apply the pads and shock the patient with 120-200 Joules on a biphasic defibrillator or 360 Joules on a monophasic defibrillator.
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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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The steps of cardiac cycle in sequence are:
Your Answer: Isovolumetric relaxation, isovolumetric contraction, ejection, passive ventricular filling, active ventricular filling
Correct Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.1st stage: diastole, or passive filling is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th stage: isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 29
Correct
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The bradycardia that occurs in patients with raised intracranial pressure is a result of the?
Your Answer: Cushing reflex
Explanation:When intracranial pressure is increased, the blood supply to RVLM neurons is compromised. This results in an increase in their discharge as a result of hypoxia and hypercapnia. The resultant rise in systemic arterial pressure (Cushing reflex) tends to restore the blood flow to the medulla.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Incorrect
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The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?
Your Answer: K
Correct Answer: Ca
Explanation:Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
