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  • Question 1 - Which of the following is true with AV nodal delay? ...

    Correct

    • Which of the following is true with AV nodal delay?

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.4
      Seconds

  • Question 2 - Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:...

    Incorrect

    • Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:

      Your Answer: Calmodulin

      Correct Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      46.8
      Seconds

  • Question 3 - Myocyte action potentials – Choose the false statement: ...

    Correct

    • Myocyte action potentials – Choose the false statement:

      Your Answer: Repolarisation is due to net k+ influx

      Explanation:

      Final repolarization (phase 3) to the resting membrane potential (phase 4) is due to closure of the Ca2+ channels and a slow, delayed increase of K+ efflux through various types of K+ channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      55.5
      Seconds

  • Question 4 - The predominant receptors in the hearts conduction system are? ...

    Incorrect

    • The predominant receptors in the hearts conduction system are?

      Your Answer: Both β1 and β2

      Correct Answer: Î’1

      Explanation:

      All of the components of the intrinsic conduction system contain autorhythmic cells that spontaneously depolarize. In the absence of extrinsic neural or hormonal influences, the SA node pacing rate would be about 100 beats per minute (bpm). The heart rate and cardiac output, however, must vary in response to the needs of the body’s cells for oxygen and nutrients under varying conditions. In order to respond rapidly to changing requirements of the body’s tissues, the heart rate and contractility are regulated by the autonomic nervous system (ANS), hormones, and other factors. The ANS has two interacting systems: the sympathetic and parasympathetic systems.

      Sympathetic receptors: There are two types of adrenergic receptors: β and α. In the cardiovascular system there are β1, β2, α1, and α2 adrenergic receptors. β1 adrenergic receptors are expressed in the heart conduction system (in the SA node, AV node, and on atrial and ventricular cardiomyocytes). The activation of β1 receptors increases heart rate (via the SA node), and contractility.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12.2
      Seconds

  • Question 5 - What is pulse pressure? ...

    Incorrect

    • What is pulse pressure?

      Your Answer: Average pressure throughout the cardiac cycle

      Correct Answer: Difference between systolic and diastolic pressure

      Explanation:

      The pulse pressure is the difference between the measured systolic and diastolic pressures.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.2
      Seconds

  • Question 6 - The AV Node: ...

    Correct

    • The AV Node:

      Your Answer: It decelerates impulses passing to the ventricles

      Explanation:

      The action potentials in the sinoatrial (SA) and atrioventricular (AV) nodes are largely due to Ca2+, with no contribution by Na+ influx. The depolarization continues to conduct slowly through the atrioventricular (AV) node. The AV node is located in the right posterior portion of the interatrial septum. This is small and bean-shaped. The atrial conductive system is organized so that the cardiac impulse does not travel from the atria into the ventricles too rapidly; this delay allows the atria to empty before ventricular contraction begins. It is the AV node and its adjacent conductive fibers that delay this transmission into the ventricles. Conduction through the AV Node is represented on the ECG by the PR interval.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.4
      Seconds

  • Question 7 - Which of the following affects the magnitude of the action potential? ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.2
      Seconds

  • Question 8 - The SA and AV nodes are usually supplied by which artery? ...

    Correct

    • The SA and AV nodes are usually supplied by which artery?

      Your Answer: Right coronary artery

      Explanation:

      The right coronary artery supplies the right atrium, right ventricle, SA and AV nodes.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.5
      Seconds

  • Question 9 - Absolute refractory period in a cardiac action potential graph occurs during. ...

    Correct

    • Absolute refractory period in a cardiac action potential graph occurs during.

      Your Answer: All of the above

      Explanation:

      Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.2
      Seconds

  • Question 10 - If both the noradrenergic and the cholinergic systems are blocked in the heart,...

    Correct

    • If both the noradrenergic and the cholinergic systems are blocked in the heart, the rate will be approximately:

      Your Answer: 100/min

      Explanation:

      The normal heart beat is about 70/min. This is due to a predominant parasympathetic activity. If sympathetic activity was unopposed the heart rate would have been 150/min. When both the noradrenergic and cholinergic systems are blocked the heart rate is 100/min. This is the normal firing rate of the SA node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.7
      Seconds

  • Question 11 - The major factor in controlling coronary artery blood flow is considered to be?...

    Correct

    • The major factor in controlling coronary artery blood flow is considered to be?

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      26.3
      Seconds

  • Question 12 - Excitation-contraction coupling in cardiac muscle involves all of the following except: ...

    Incorrect

    • Excitation-contraction coupling in cardiac muscle involves all of the following except:

      Your Answer: ATP hydrolysis

      Correct 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      99.8
      Seconds

  • Question 13 - Calcium is mobilized from the sarcoplasmic reticulum through: ...

    Correct

    • Calcium is mobilized from the sarcoplasmic reticulum through:

      Your Answer: Ryanodine receptor (RyR2) calcium release channels

      Explanation:

      During the plateau phase of the action potential, calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors. As a result intracellular calcium increases binding to troponin C resulting in contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11
      Seconds

  • Question 14 - Which of the atrial pressure changes represents the a-wave of the JVP ...

    Correct

    • Which of the atrial pressure changes represents the a-wave of the JVP

      Your Answer: Atrial systole

      Explanation:

      The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.1
      Seconds

  • Question 15 - Concerning surface anatomy, where is the mitral valve found? ...

    Incorrect

    • Concerning surface anatomy, where is the mitral valve found?

      Your Answer: Situated in the 4th intercostal space in the mid clavicular line

      Correct Answer: Situated in the 4th intercostal space to the left of the sternum

      Explanation:

      The mitral valve is situated in the left 4th intercostal space just beneath the sternum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      26.9
      Seconds

  • Question 16 - Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly...

    Correct

    • Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly during:

      Your Answer: Diastole

      Explanation:

      The sub endocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure from contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the sub endocardium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.6
      Seconds

  • Question 17 - The direct determinants of cardiac output are ...

    Correct

    • 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]

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.9
      Seconds

  • Question 18 - Coronary arteries arise from? ...

    Incorrect

    • Coronary arteries arise from?

      Your Answer: Ascending aorta

      Correct Answer: None of the above

      Explanation:

      Coronary arteries arise from the sinuses behind 2 of the cusps of the aortic valve at the root of aorta.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.5
      Seconds

  • Question 19 - Select the correct statement regarding the 4th heart sound, it? ...

    Incorrect

    • Select the correct statement regarding the 4th heart sound, it?

      Your Answer: Coincides with rapid ventricular filling.

      Correct Answer: Can be heard in atrial systole.

      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 by atrial systole.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.7
      Seconds

  • Question 20 - The effects of β1 stimulation include the following ...

    Correct

    • The effects of β1 stimulation include the following

      Your Answer: Increased strength of contraction

      Explanation:

      β1 stimulation include the phosphorylation of L type Ca++ channels and phospholamban and increased Ca++ influx from myocytes.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      28.7
      Seconds

  • Question 21 - Which of the following suggests the presence of mitral regurgitation as well as...

    Incorrect

    • Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?

      Your Answer: Loud P2

      Correct Answer: Displaced apex beat

      Explanation:

      Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      186.8
      Seconds

  • Question 22 - Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms ...

    Incorrect

    • Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms

      Your Answer: Down regulation of phospholambin

      Correct Answer: Increased phosphorylation of phosholamban

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      32.7
      Seconds

  • Question 23 - Regarding blood supply to the heart; ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      19
      Seconds

  • Question 24 - In the blood supply of the heart, ‘dominance’ refers to the coronary artery...

    Incorrect

    • In the blood supply of the heart, ‘dominance’ refers to the coronary artery which supplies the?

      Your Answer: Anterior interventricular artery

      Correct Answer: Posterior interventricular artery

      Explanation:

      Dominance of the coronary artery system is defined by the artery that gives rise to the posterior interventricular artery. Dominance of the right coronary artery is more common (68%). It gives rise to the large posterior interventricular branch which goes down to the apex of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.3
      Seconds

  • Question 25 - Which of the following isoforms of Nitric oxide synthase (NOS) is found in...

    Correct

    • Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?

      Your Answer: Nos 3

      Explanation:

      There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.4
      Seconds

  • Question 26 - Coronary arteries fill up during ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.5
      Seconds

  • Question 27 - The coronary arteries fill during? ...

    Correct

    • The coronary arteries fill during?

      Your Answer: Diastole

      Explanation:

      During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.2
      Seconds

  • Question 28 - In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?...

    Incorrect

    • In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?

      Your Answer: Kidneys

      Correct Answer: Liver

      Explanation:

      The liver is the organ which contains sinusoidal capillaries with discontinuous endothelium. The brain, lungs and the intestine all contain continuous capillaries, however the kidney contains fenestrated capillaries to aid in filtration.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      34.8
      Seconds

  • Question 29 - What is a characteristic findings on ECG in hyperkalaemia? ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.2
      Seconds

  • Question 30 - The function of Troponin T in cardiac muscle is? ...

    Correct

    • The function of Troponin T in cardiac muscle is?

      Your Answer: Allows attachment of troponin components to tropomyosin

      Explanation:

      Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin, and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      19.1
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (19/30) 63%
Medicine (19/30) 63%
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