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Question 1
Correct
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Question 2
Correct
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Factors influencing cardiac output include which of the following?
Your Answer: All of the above
Explanation:There is a correlation between resting CO and body surface area. The output per min per square meter of body surface (the cardiac index) averages 3.2l.
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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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The coronary arteries supply which part of the heart’s subendocardial region exclusively in diastole?
Your Answer: Left ventricle
Explanation:It is only during diastole that the blood flows to the subendocardial portion of the left ventricle, as the heart muscle relaxes and the coronary arteries regain their patency.
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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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Activation of baroreceptor reflex involves:
Your Answer: Short term regulation of systemic blood pressure
Explanation:Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.
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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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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 6
Correct
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Which of the following antiarrhythmic drugs may be used in the treatment of long QT syndrome?
Your 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 7
Correct
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The following determines the strength of contraction
Your Answer: Plateau phase
Explanation:The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction
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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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The coronary sinus, which empties into the right atrium, serves to?
Your Answer: Drain the venous supply of the myocardium
Explanation:The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.
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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 is NOT associated with the development of aortic regurgitation?
Your 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 10
Incorrect
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Where on the surface of the chest is the normal site of auscultation for the mitral area?
Your Answer: 5th left intercostal space mid-axillary line
Correct Answer: 4th left intercostal space in the mid-clavicular line
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum, in the mid clavicular line.
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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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In the Fick‘s method of measuring cardiac output, the arterial oxygen content can be measured in a sample obtained from
Your Answer: The pulmonary vein
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Note that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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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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The following is true in relation to coronary venous drainage?
Your Answer: Most venous return ultimately drains into right atrium via the coronary sinus
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Correct
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Which of the following normally has a slow depolarizing “prepotential”?
Your 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 14
Correct
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What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?
Your Answer: To detect hypokalaemia
Explanation:All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.
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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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Question 16
Correct
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Water hammer pulse is found in:
Your Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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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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Which of the following is true of the Natriuretic hormones?
Your Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Correct
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Question 20
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 21
Correct
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Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.
Your Answer: ATP
Explanation:A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.
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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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The direct determinants of cardiac output are
Your Answer: Stroke volume and heart rate
Explanation:Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]
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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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In which area is depolarization initiated?
Your Answer: SA node
Explanation:SA node is the pacemaker of the heart. It determines the rate of contractions. It is the place where depolarization is initiated. It exhibits phase 4 depolarization or automaticity. Electrical impulses then spread to the AV node, purkinje fibers, bundle of his and the ventricular muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Correct
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During exercise, a man consumes 2L O2/min, his arterial 02 content is 190 ml/l and the 02 content of his mixed venous blood is 130ml/l. His cardiac output is approximately:
Your Answer: 33l/min
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Therefore CO = 2/(0.190-0.130) = 33l/minNote that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Correct
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What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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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 are responsible for the 4th heart sound?
Your Answer: Ventricular hypertrophy
Explanation:The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.
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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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Which of the following factors serve to decrease cardiac output?
Your 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 28
Correct
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Regarding cardiac muscle contractility, the afterload refers to:
Your Answer: The resistance against which blood is expected
Explanation:The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.
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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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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 30
Incorrect
SESSION STATS - PERFORMANCE PER SPECIALTY
