Body Fluids and Circulation Question 50
50. A specialised nodal tissue embedded in the lower corner of the right atrium, close to Atrioventricular septum, delays the spreading of impulses to heart apex for about $0.1 sec$.
This delay allows
[2019]
(a) the atria to empty completely.
(b) blood to enter aorta.
(c) the ventricles to empty completely.
(d) blood to enter pulmonary arteries.
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Answer : a
Hints & Solutions
(a) The delay in transmission of impulse from SAN to the ventricles provided by AVN prevents simultaneous contraction of ventricles and auricles. This allows atria to empty completely before ventricles start contraction.
