Write about the function of heart.

Explanation

The function of heart in the circulatory sys- tem is like a pump.
(a) The sequence of events that occur repeat- edly in the heart is called cardiac cycle.
(b) There are two phases of cardiac cycle : diastole phase and systole phase.
(c) In the diastole phase, the heart gets filled with the blood and ventricles relax.
(d) In the systole phase, the ventricles con- tract and the outflow of the blood cakes place from the heart to the arteries.
(e) Thus, one cardiac cycle gets completed and one contraction (systole) and one relaxation (diastole) causes one heartbeat.
(f) Heartbeats due to this rhythmic contrac- tion and relaxation of the heart muscle.