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  • Question 1 - In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.1
      Seconds

  • Question 2 - Sinus bradycardia may be caused by disease of which of the following: ...

    Correct

    • Sinus bradycardia may be caused by disease of which of the following:

      Your Answer: Right coronary artery

      Explanation:

      Disease of the right coronary artery may cause sinus bradycardia and AV nodal block.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7
      Seconds

  • Question 3 - The rate of depolarization of the SA node membrane potential is modulated by...

    Incorrect

    • The rate of depolarization of the SA node membrane potential is modulated by the following:

      Your Answer: Autonomic tone

      Correct Answer: All of the above

      Explanation:

      Rate of depolarization of the SA node is modulated by all of these.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.2
      Seconds

  • Question 4 - Which of the following causes the closure of the ductus arteriosus during birth?...

    Correct

    • Which of the following causes the closure of the ductus arteriosus during birth?

      Your Answer: Reduced levels of prostaglandins

      Explanation:

      Ductus arteriosus is kept open by the prostaglandin E2 which is a vasodilator. At birth the high levels of cyclooxygenase blocks the production of prostaglandins which results in the closure of the ductus arteriosus.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.2
      Seconds

  • Question 5 - AV valves open during? ...

    Incorrect

    • AV valves open during?

      Your Answer: Isovolumetric contraction of ventricles

      Correct Answer: Early diastole

      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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      34
      Seconds

  • Question 6 - Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:...

    Correct

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

      Your 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
      20.9
      Seconds

  • Question 7 - The coronary sinus drains into the: ...

    Correct

    • The coronary sinus drains into the:

      Your Answer: Right atrium

      Explanation:

      The coronary sinus drains into the right atrium. 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.4
      Seconds

  • Question 8 - Myocardium requires more oxygen to expel blood in: ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.5
      Seconds

  • Question 9 - In Starling’s law of the heart, the decrease in tension developed by muscle...

    Incorrect

    • In Starling’s law of the heart, the decrease in tension developed by muscle contraction at high degrees of stretch is due to:

      Your Answer: A decrease in the number of cross bridges between myosin and actin

      Correct Answer: Disruption of myocardial fibers

      Explanation:

      Starling law states that the force of contraction is directly proportional to the preload. When the heart muscle is stretched beyond its limit the tension that is developed decreases, this is not due to loss of formation of effective myosin and actin cross bridges. The heart muscles despite being fully stretched is never stretched to this point. The reason for this decreased tension is physical disruption of the myocardial fibers.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.3
      Seconds

  • Question 10 - Which of the following components regulate cardiac output? ...

    Correct

    • Which of the following components regulate cardiac output?

      Your Answer: All of the above

      Explanation:

      Cardiac output is regulated by the autonomic nervous system with sympathetic nerves having a positive chronotropic and inotropic effect and parasympathetic nerves having the opposite effect. An increase in preload will increase cardiac output likewise an afterload increase will also increase cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10
      Seconds

  • Question 11 - Which of the following concerning PR interval is INCORRECT? ...

    Incorrect

    • Which of the following concerning PR interval is INCORRECT?

      Your Answer: PR interval shorten during exercise

      Correct Answer: Always measured from the beginning of p wave to the beginning of r wave

      Explanation:

      The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization. The PR interval is only measured from the beginning of P wave to beginning of R wave if the Q wave is absent.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      28.3
      Seconds

  • Question 12 - Which of the following conditions has no effect on cardiac output? ...

    Correct

    • Which of the following conditions has no effect on cardiac output?

      Your Answer: Sleep

      Explanation:

      Sleep has no effect on the cardiac output. Anxiety, excitement and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.5
      Seconds

  • Question 13 - The T-tubular system in cardiac muscle is: ...

    Correct

    • The T-tubular system in cardiac muscle is:

      Your Answer: Transmits action potential from sarcolemma to the SR to allow for Ca2+ release into the cytoplasm

      Explanation:

      Action potentials are 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, which are voltage gated calcium channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.6
      Seconds

  • Question 14 - Which vaso metabolite decreases coronary blood flow? ...

    Correct

    • Which vaso metabolite decreases coronary blood flow?

      Your Answer: Endothelin

      Explanation:

      Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.5
      Seconds

  • Question 15 - 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
      6.5
      Seconds

  • Question 16 - Activation of baroreceptor reflex involves: ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.8
      Seconds

  • Question 17 - In a 30 year old male with hypertrophic obstructive cardiomyopathy (HOCM), which of...

    Incorrect

    • In a 30 year old male with hypertrophic obstructive cardiomyopathy (HOCM), which of the following is not associated with increased risk of sudden death?

      Your Answer: Unexplained syncope

      Correct Answer: Age

      Explanation:

      Hypertrophic cardiomyopathy (HCM) is a disease in which a portion of the myocardium (heart muscle) is enlarged without any obvious cause, creating functional impairment of the heart. It is the leading cause of sudden death in young athletes. The major risk factors for sudden death (SD) are recent unexplained syncope unlikely to be neurocardiogenic; HCM-related SD in first-degree or other close relatives; repetitive and/or prolonged nonsustained ventricular tachycardia (NSVT) episodes on Holter or extended ambulatory monitoring; massive left ventricular hypertrophy (LVH) (wall thickness ≥30 mm); extensive/diffuse late gadolinium enhancement (LGE); end-stage heart failure usually with systolic dysfunction; and thin-walled akinetic LV apical aneurysm with regional scarring.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13
      Seconds

  • Question 18 - 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: Localised tapping apex beat

      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
      9.3
      Seconds

  • Question 19 - Heart rate can be slowed by: ...

    Correct

    • Heart rate can be slowed by:

      Your Answer: Grief

      Explanation:

      Grief stimulates the parasympathetic nervous system, resulting in a decrease in the heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.8
      Seconds

  • Question 20 - The basic unit of contraction in myocytes is: ...

    Correct

    • The basic unit of contraction in myocytes is:

      Your Answer: Sarcomere

      Explanation:

      Sarcomere is the organelle where calcium is stored to be released during contraction of the muscle. It is the basic unit of contraction in striated muscle fibers. As myocytes are also striated muscles, sarcomeres also forms the basic unit of contraction. The impulses travel along the membrane and via its interaction with the dihydropyridine receptors it releases the stored calcium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.4
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (14/20) 70%
Medicine (14/20) 70%
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