Cardiovascular System MCQs

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| By Catherine Halcomb
Catherine Halcomb
Community Contributor
Quizzes Created: 1429 | Total Attempts: 6,065,044
Questions: 15 | Attempts: 426

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Cardiovascular System MCQs - Quiz

This informative quiz on Cardiovascular system contains wide-ranging questions that will enhance your conceptual knowledge about the cardiovascular system. This quiz will help you in your last-minute revision before the exam, so if you are looking to test your knowledge, this is the quiz for you. If you find this quiz informative was learned something new from it, make sure you share it with your friends and peers. All the best!


Questions and Answers
  • 1. 

    Hyperemia in skeletal muscle during exercise is normally associated with: 

    • A.

      Release of sympathetic vasoconstrictor tone in the exercising muscles

    • B.

      Capillary dilation clue to relaxation or capillary smooth muscle

    • C.

      A fall in arterial pressure·

    • D.

      Reflex vasoconstriction in other vascular beds

    • E.

      An increase in venous pressure

    Correct Answer
    D. Reflex vasoconstriction in other vascular beds
    Explanation
    During exercise, there is an increased demand for oxygen and nutrients in the skeletal muscles. This leads to vasodilation in the exercising muscles, allowing for increased blood flow to meet the increased demand. However, this vasodilation can also lead to a decrease in blood pressure. In order to maintain blood pressure and ensure adequate blood flow to other organs, reflex vasoconstriction occurs in other vascular beds. This vasoconstriction helps redistribute blood flow and maintain overall blood pressure during exercise.

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  • 2. 

    Sino-atrial node cells are:

    • A.

      Found in both atria

    • B.

      Innervated by the somatic nerves

    • C.

      Unable to generate impulses when completely denervated

    • D.

      Connected to the atrioventricular node by fine bundles of Purkinje tissue

    • E.

      Able to self-generate impulses because their membrane potential is unstable

    Correct Answer
    E. Able to self-generate impulses because their membrane potential is unstable
    Explanation
    Sino-atrial node cells are able to self-generate impulses because their membrane potential is unstable. This means that these cells have the ability to spontaneously depolarize and generate electrical impulses without any external stimulation. This is a crucial characteristic of the sino-atrial node, as it serves as the natural pacemaker of the heart, initiating the electrical signals that regulate the heartbeat. The unstable membrane potential allows for the regular and rhythmic contractions of the heart, ensuring its proper functioning.

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  • 3. 

    The first heart sound corresponds in time with:

    • A.

      Closure of the aortic and pulmonary valves

    • B.

      The P wave of the electrocardiogram

    • C.

      A decline in atrial pressure

    • D.

      A rise in ventricular pressure

    • E.

      The A wave in central venous pressure

    Correct Answer
    D. A rise in ventricular pressure
    Explanation
    The first heart sound corresponds in time with a rise in ventricular pressure. This is because the first heart sound, also known as S1, is produced by the closure of the atrioventricular valves (mitral and tricuspid valves) when the ventricles contract and the pressure inside them increases. This closure prevents the backflow of blood into the atria and marks the beginning of systole, the contraction phase of the cardiac cycle.

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  • 4. 

    The absolute refractory period in the heart:

    • A.

      Corresponds to the duration of relaxation

    • B.

      Lasts ti11 half of cardiac contraction

    • C.

      Is shorter than the refractory period in skeletal muscle

    • D.

      Lasts till the end of the first third of cardiac relaxation

    • E.

      Last only 10 ms

    Correct Answer
    D. Lasts till the end of the first third of cardiac relaxation
    Explanation
    The absolute refractory period in the heart refers to the period of time during which the cardiac muscle is unable to respond to any additional stimulation, regardless of the strength of the stimulus. This period lasts until the end of the first third of cardiac relaxation, meaning that the heart cannot be excited or contract during this time. This is important for ensuring that the heart has enough time to relax and refill with blood before the next contraction.

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  • 5. 

    The strength of contraction of the left ventricular muscle increases when:

    • A.

      End-diastolic ventricular filling pressure rises

    • B.

      Serum potassium levels rise

    • C.

      Blood calcium levels fall

    • D.

      Blood magnesium levels fall

    • E.

      Peripheral resistance is decreased

    Correct Answer
    A. End-diastolic ventricular filling pressure rises
    Explanation
    When the end-diastolic ventricular filling pressure rises, it means that there is an increased volume of blood filling the left ventricle during diastole. This increased volume stretches the ventricular muscle fibers, leading to a stronger contraction during systole. As a result, the strength of contraction of the left ventricular muscle increases. This is known as the Frank-Starling mechanism, which ensures that the heart pumps out the same amount of blood that it receives.

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  • 6. 

    When Parasympaticus is activated, there is:

    • A.

      Hypertension

    • B.

      Tachycardia

    • C.

      Bradycardia

    • D.

      Increase in Stroke Volume (SV)

    • E.

      None of the above

    Correct Answer
    C. Bradycardia
    Explanation
    When the parasympathetic nervous system, specifically the parasympatheticus, is activated, it leads to bradycardia. Bradycardia refers to a slower than normal heart rate. This occurs because the parasympatheticus releases acetylcholine, which slows down the electrical signals in the heart and decreases the heart rate. As a result, the heart beats at a slower pace, leading to bradycardia.

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  • 7. 

    Cardiac Output (C.O.):

    • A.

      It is normally expressed as the output of each of the ventricles in liter per minute

    • B.

      Is about 2.0 I at rest

    • C.

      Is about 10.0 I at rest

    • D.

      Rises in a cold environment

    • E.

      Does not increase in exercise following denervation of the heart

    Correct Answer
    A. It is normally expressed as the output of each of the ventricles in liter per minute
    Explanation
    Cardiac Output (C.O.) refers to the amount of blood pumped by each ventricle of the heart in one minute. It is typically measured in liters per minute. This measurement is important in assessing the overall efficiency of the heart and its ability to meet the body's demands for oxygen and nutrients. A normal resting cardiac output is around 5 liters per minute, with each ventricle contributing approximately 2.5 liters. In certain conditions, such as exercise or exposure to cold, the cardiac output may increase to meet the increased demand for oxygen and heat distribution. However, denervation of the heart, which involves the interruption of nerve supply, can lead to a lack of response in cardiac output during exercise.

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  • 8. 

    In the brachial artery:

    • A.

      Pulse waves travel at the same velocity as blood

    • B.

      Pulse pressure falls with decreasing elasticity of the wall

    • C.

      Pressure rises markedly when the artery is occluded distally

    • D.

      Pressure falls when the arm is raised above a head level

    • E.

      Pulse pressures have a smaller amplitude than aortic pulse pressures

    Correct Answer
    D. Pressure falls when the arm is raised above a head level
    Explanation
    When the arm is raised above head level, the gravitational force causes blood to flow downwards, away from the brachial artery. This reduces the amount of blood in the artery and therefore decreases the pressure within it. As a result, the pressure falls when the arm is raised above head level.

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  • 9. 

    From a functional point of view, arterioles:

    • A.

      Allow exchange of water, salts, electrolytes, hormones, and other substances between plasma and tissues in both directions

    • B.

      Contraction is a bigger part of the blood volume

    • C.

      Decrease the big fluctuations in blood plasma during the cardiac cycle

    • D.

      Form the resistance against the ventricular contractions

    • E.

      Play the role of reservoirs of blood from the capillaries

    Correct Answer
    D. Form the resistance against the ventricular contractions
    Explanation
    Arterioles form the resistance against the ventricular contractions. This means that they regulate the flow of blood from the heart to the capillaries by constricting or dilating. By constricting, arterioles increase resistance and reduce blood flow, while by dilating, they decrease resistance and increase blood flow. This resistance is important for maintaining blood pressure and ensuring that blood is distributed appropriately to different tissues and organs in the body.

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  • 10. 

    In a denervated heart, the left ventricular stroke volume increases when the:

    • A.

      End-diastole length of the ventricular fiber increases

    • B.

      Peripheral resistance decreases

    • C.

      Blood volume falls

    • D.

      Right ventricular output decreases.

    • E.

      Veins dilate

    Correct Answer
    A. End-diastole length of the ventricular fiber increases
    Explanation
    When the end-diastole length of the ventricular fiber increases, it means that the heart muscle is stretched more during diastole, which allows it to contract more forcefully during systole. This increased contractility leads to a higher stroke volume, which is the amount of blood pumped out of the left ventricle with each heartbeat. Therefore, the correct answer is that the left ventricular stroke volume increases when the end-diastole length of the ventricular fiber increases.

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  • 11. 

    The greater the distance from the heart is, the arterial:

    • A.

      Walls contain relatively more smooth muscle fibers than elastic

    • B.

      Flow has a greater tendency to be turbulent

    • C.

      Mean pressure tends to decrease slightly

    • D.

      Pulse pressure tends to increase slightly

    • E.

      PO2 falls appreciably

    Correct Answer
    A. Walls contain relatively more smooth muscle fibers than elastic
    Explanation
    As the distance from the heart increases, the arterial walls contain relatively more smooth muscle fibers than elastic. This is because the smooth muscle fibers provide the necessary contractility and control of blood flow in the smaller arteries and arterioles, which are located further away from the heart. The elastic fibers, on the other hand, are more abundant in the larger arteries closer to the heart, allowing them to stretch and recoil to accommodate the pulsatile flow of blood.

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  • 12. 

    The heart rate is decreased when:

    • A.

      Atropine is injected

    • B.

      Vagus is stimulated

    • C.

      Glucocorticoids are injected

    • D.

      Ca2+ is applied

    • E.

      Adrenaline is injected

    Correct Answer
    B. Vagus is stimulated
    Explanation
    When the vagus nerve is stimulated, it releases acetylcholine, which binds to muscarinic receptors on the heart. This activation leads to a decrease in heart rate through a series of intracellular signaling pathways. Therefore, the correct answer is vagus is stimulated.

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  • 13. 

    Systemic hypertension may be caused by:

    • A.

      Hypoxia due to chronic respiratory failure

    • B.

      The excessive secretion of aldosterone

    • C.

      Excessive secretion of insulin

    • D.

      Myocardial thickening (hypertrophy) of the left ventricle

    • E.

      The rapid cardiac action of ventricular fibrillation

    Correct Answer
    B. The excessive secretion of aldosterone
    Explanation
    Excessive secretion of aldosterone can cause systemic hypertension. Aldosterone is a hormone produced by the adrenal glands that regulates the balance of salt and water in the body. When there is an excessive secretion of aldosterone, it can lead to an increase in sodium reabsorption and water retention, which in turn raises blood pressure. This can occur in conditions such as primary aldosteronism or adrenal adenoma, where there is an abnormal overproduction of aldosterone.

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  • 14. 

    The main factor determining the diastolic blood pressure is:

    • A.

      The volume of blood

    • B.

      Viscosity of blood

    • C.

      Cardiac performance

    • D.

      Peripheral vascular resistance

    • E.

      The length of the blood vessel

    Correct Answer
    D. Peripheral vascular resistance
    Explanation
    Diastolic blood pressure is the pressure in the arteries when the heart is at rest between beats. Peripheral vascular resistance refers to the resistance that the blood encounters as it flows through the blood vessels. It is determined by factors such as the diameter of the blood vessels, the elasticity of the vessel walls, and the viscosity of the blood. When peripheral vascular resistance is high, it causes an increase in diastolic blood pressure. Therefore, peripheral vascular resistance is the main factor determining diastolic blood pressure.

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  • 15. 

    Ln atrial fibrillation:

    • A.

      The electrocardiogram shows no evidence of atrial activity

    • B.

      The ventricular rate is lower than the atrial rate

    • C.

      Respiratory sinus arrhythmia can usually be registered

    • D.

      The ventricular rate is higher than the atrial rate

    • E.

      The QRS complex has an abnormal configuration

    Correct Answer
    B. The ventricular rate is lower than the atrial rate
    Explanation
    In atrial fibrillation, the normal electrical signals in the heart are disrupted, causing the atria to quiver instead of contracting properly. This results in the absence of coordinated atrial activity, which is reflected in the electrocardiogram (ECG) as no evidence of atrial activity. Additionally, in atrial fibrillation, the ventricular rate (heartbeat) is typically lower than the atrial rate because the irregular and chaotic electrical signals from the atria fail to reach and fully activate the ventricles. Therefore, the correct answer is "The ventricular rate is lower than the atrial rate."

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Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Nov 16, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Apr 20, 2023
    Quiz Created by
    Catherine Halcomb
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