NEET Zoology Heart & Circulation MCQ Question
Which combination of statements about the heart's electrical conduction system and its function is correct?
The sino-atrial node initiates the heartbeat, and the atrioventricular node coordinates the contraction of the ventricles.
The ventricles contract before the atria, and the heart is regulated by external hormonal signals only.
The atrioventricular node generates the action potential and the sino-atrial node is responsible for the heart rate.
The heart's contraction is solely dependent on the autonomic nervous system, and valves prevent backflow of blood.
Correct Answer
Detailed Explanation
The sino-atrial node functions as the pacemaker of the heart, initiating the heartbeat, while the atrioventricular node coordinates the contraction of the ventricles. This aligns with the NCERT context that describes the roles of the nodal tissue in heart function.
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