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A : The cardiac impulse which originates...

A : The cardiac impulse which originates from SA node in mammalian heart cannot spread directly from atria to ventricles
R : In mammalian heart there is no continuity between cardiac muscle fibres of atria and those of ventricles except AV bundles.

A

If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.

B

If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.

C

If Assertion is true, but Reason is false.

D

If both Assertion and Reason are false.

Text Solution

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The correct Answer is:
A
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Explore conceptually related problems

Indicate whether the following statements are true of false : (a) Both auricles of amphibian heart open into the same ventricle. (b) Prawn's heart carries only oxygenated blood. (c ) Purkinje fibres are nerve fibres supplying the ventricular muscles. (d) The first heart sound results from a closure of semilunar valves. (e ) The vagus nerve reduces the heart rate. (f) The A-V node normally initiates the cardiac impulse. (g) Semilunar valves open during the ventricular diastole.

Which of the following statement(s) is/are correct? I. Bundle of His originates from the SA-node. SA-node is situated in the wall of right auricle. III. Auricular contraction stimulates the AV-node. IV. AV-node sets up the cardiac impulses 72 times per minute. Choose the correct answer.

Knowledge Check

  • Assertion : The AV bundle is essential for the conduction of cardiac impulse. Reason: There is no continuity between the cardiac muscle fibers of the auricles and those of the ventricles.

    A
    If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
    B
    If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
    C
    If Assertion is true, but Reason is false.
    D
    If both Assertion and Reason are false.

  • In order for the blood to flow from right ventricle to left ventricle in mammalian heart, it must flow through

    A
    Right ventricle, pulmonary arteries Lungs Pulmonary veins, Left atrium
    B
    Right ventricle, Pulmonary veins, Lungs Pulmonary arteries, Left atrium
    C
    Right ventricle, Right atrium lungs pulmonary veins Left atrium
    D
    Right ventricle , systemic aorta lungs pulmonary veins left atrium

  • The problem of electrical discontinuity caused in the normal heart by the connective tissue separating the atria from the ventricles is solved by

    A
    coordinating electrical activity in the atria with electrical activity in the ventricles by connecting them via the bundle of His
    B
    having the A-V node function as a secondary pacemaker
    C
    having an ectopic pacemaker
    D
    coordinating electrical activity in the atria with electrical activity in the venticles by connecting them via the vagus nerve

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    Explore conceptually related problems

    Read the following statements and select the correct ones (i) Nodal tissue is specialised cardiac musculature in human heart which has the ability to generate action potential due to an external stimuli (ii) Position of SAN - right corner of right atrium (iii) Position of AVN - right corner of ventricle (iv) AV bundle continues from AVN (v) Purkinje fibres are modified cardiac muscle fibres that originate from the atrioventricular node and spread into the two ventricles.

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