When the SA node generates an action potential, it stimulates the atrial systole, which results in

Question

When the SA node generates an action potential, it stimulates the atrial systole, which results in (A) complete ventricular filling (B) complete emptying of atria (C) increased flow of blood into the ventricles by about 30%, but semilunar valves must be open (D) increased flow of blood into the ventricle by about 30% but semilunar valves must be closed

Tardigrade Admin · Accepted Answer

Conduction system of the heart consists of SA node, AV node, Bundle of His, and Purkinje fibers. This system is responsible for contraction and relaxation of heart i.e. systole and diastole which constitutes the cardiac cycle. As SA node begins its conduction, the atria begin to contract, as a result of which the AV valves open and blood from atria enter the ventricles. During this phase, the ventricles are in a relaxed state and thus the semilunar valves are closed. The blood flow is increased by 30% from auricle to ventricle.

Q. When the SA node generates an action potential, it stimulates the atrial systole, which results in

complete ventricular filling

complete emptying of atria

increased flow of blood into the ventricles by about 30%, but semilunar valves must be open

increased flow of blood into the ventricle by about 30% but semilunar valves must be closed