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  • Question 1 - Activation of nitric oxide synthesis by endothelial cells is triggered by: ...

    Correct

    • Activation of nitric oxide synthesis by endothelial cells is triggered by:

      Your Answer: All of the above

      Explanation:

      Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      31.1
      Seconds

  • Question 2 - The heart rate can be accelerated by: ...

    Correct

    • The heart rate can be accelerated by:

      Your Answer: Exercise and thyroid hormones

      Explanation:

      The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.2
      Seconds

  • Question 3 - The Sinoatrial node in the majority of people is supplied by the? ...

    Correct

    • The Sinoatrial node in the majority of people is supplied by the?

      Your Answer: Right coronary artery

      Explanation:

      In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.3
      Seconds

  • Question 4 - The following contributes to the rate of depolarization? ...

    Correct

    • The following contributes to the rate of depolarization?

      Your Answer: All of the options given

      Explanation:

      Depolarization occurs due to impulses generated by the SA node. As the heart beats to the rhythm of the SA node, certain factors will effect the rate of depolarization. All the mentioned options effect the rate of depolarization.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.1
      Seconds

  • Question 5 - Which one of the following is a risk factor for torsade de pointes?...

    Correct

    • Which one of the following is a risk factor for torsade de pointes?

      Your Answer: Hypothermia

      Explanation:

      The following is a list of factors associated with an increased tendency toward torsades de pointes:- Hypokalaemia (low blood potassium)- Hypomagnesemia (low blood magnesium)- Hypocalcaemia (low blood calcium)- Bradycardia (slow heartbeat)- Heart failure- Left ventricular hypertrophy- Hypothermia- Subarachnoid haemorrhage- Hypothyroidism

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.1
      Seconds

  • Question 6 - AV valves open during? ...

    Correct

    • AV valves open during?

      Your 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
      9.6
      Seconds

  • Question 7 - The function of ATP in cardiac muscle contraction includes: ...

    Correct

    • The function of ATP in cardiac muscle contraction includes:

      Your Answer: Binding to myosin after the power stroke to allow uncoupling of actin and myosin

      Explanation:

      After calcium binds to the troponin C, there is a conformational change in the structure of troponin I and tropomyosin, which moves out of the way and frees the site where myosin can bind to actin. This results in the formation of the cross linkage of the actin and myosin giving rise to the power stroke in the contraction phase. This occurs with the release of ADP. When ATP combines to this complex it breaks and the cycle repeats itself.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.9
      Seconds

  • Question 8 - The amount of a substance taken up by an organ (or whole body)...

    Incorrect

    • 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 Poiseuille – Hagen principle

      Correct 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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      38.4
      Seconds

  • Question 9 - All valves are closed in which phase of the cardiac cycle? ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6
      Seconds

  • Question 10 - In a normal heart rate at rest, the left ventricular end-diastolic volume is...

    Correct

    • 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).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.6
      Seconds

  • Question 11 - Which of the following normally has a slow depolarizing “prepotential”? ...

    Incorrect

    • Which of the following normally has a slow depolarizing “prepotential”?

      Your Answer: Ventricular 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      18
      Seconds

  • Question 12 - 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
      6.2
      Seconds

  • Question 13 - 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
      3.3
      Seconds

  • Question 14 - Which of the following occurs during a Valsalva manoeuvre? ...

    Correct

    • 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:

      1. 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.
      2. 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.
      3. Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
      4. 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4
      Seconds

  • Question 15 - Coronary flow is reduced during ...

    Correct

    • Coronary flow is reduced during

      Your Answer: Tachycardia

      Explanation:

      Maximum amount of blood flow in the coronary arteries occur during diastole. When the heart rate increases which is also called tachycardia the duration of diastole decreases. Hence the amount of blood flow to the cardiac muscle also decreases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.8
      Seconds

  • Question 16 - 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
      17.8
      Seconds

  • Question 17 - The Plateau phase in myocyte action potentials does all of the following except:...

    Correct

    • The Plateau phase in myocyte action potentials does all of the following except:

      Your Answer: It allows early reactivation of the myocytes

      Explanation:

      The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. 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 (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.2
      Seconds

  • Question 18 - 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
      6.3
      Seconds

  • Question 19 - Describe the location of the SA node: ...

    Correct

    • Describe the location of the SA node:

      Your Answer: Junction of the SVC and right atrium

      Explanation:

      Anatomically the SA node is located at the junction of the superior vena cava and the right atrium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.3
      Seconds

  • Question 20 - During which phase of the cardiac cycle does most of the ventricular filling...

    Correct

    • During which phase of the cardiac cycle does most of the ventricular filling occur?

      Your Answer: Ventricular diastole

      Explanation:

      During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      820.3
      Seconds

  • Question 21 - Where is the carotid sinus located? ...

    Correct

    • Where is the carotid sinus located?

      Your Answer: After the bifurcation of the carotid artery, on the internal carotid

      Explanation:

      The carotid sinus is a small dilation in the internal carotid artery just above its bifurcation into the external and internal carotid branch. Baroreceptors are present at this dilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.7
      Seconds

  • Question 22 - Endothelial cells produce the following substance(s): ...

    Correct

    • Endothelial cells produce the following substance(s):

      Your Answer: All of the above

      Explanation:

      Endothelial cells produce thromboxane, prostacyclins, nitric oxides, endothelins, IL-1 and TNF.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.7
      Seconds

  • Question 23 - The ‘c’ wave in JVP corresponds more closely with: ...

    Correct

    • The ‘c’ wave in JVP corresponds more closely with:

      Your Answer: Isovolumetric contraction

      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 (peaks) and two downward deflections (troughs) 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).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8
      Seconds

  • Question 24 - Endothelial cells are attached to adjacent cells by adherent junctions via: ...

    Correct

    • Endothelial cells are attached to adjacent cells by adherent junctions via:

      Your Answer: Cadherins

      Explanation:

      Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.7
      Seconds

  • Question 25 - 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
      5.2
      Seconds

  • Question 26 - Factors influencing cardiac output include which of the following? ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      4.2
      Seconds

  • Question 27 - 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
      5.9
      Seconds

  • Question 28 - Vasodilatation of coronary arteries is caused by: ...

    Correct

    • Vasodilatation of coronary arteries is caused by:

      Your Answer: Hypoxia

      Explanation:

      The heart is highly metabolically active and boasts the highest oxygen consumption by mass of any organ. This demand for oxygen is met by the coronary circulation, which is responsible for delivering blood to the myocardium and represents approximately 5% of cardiac output. Vasodilation may be due to the local effect of hypoxia on coronary vessels, or local metabolic vasodilation, or the activation of β-adrenoceptors or some combination of these mechanisms.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.3
      Seconds

  • Question 29 - 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
      23.5
      Seconds

  • Question 30 - The end- diastolic ventricular volume is about? ...

    Correct

    • The end- diastolic ventricular volume is about?

      Your Answer: 130 ml

      Explanation:

      The end diastolic volume in a healthy individual is about 130 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      3.1
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (28/30) 93%
Medicine (28/30) 93%
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