differentiate between ststone and diastole explain the conduction of heart best .

Explanation

One complete contraction (Systole) and relaxation (diastole) of the atrium and ventricles of the heart constitutes Heartbeat.
The human heart is myogenic. Contraction is initiated by sino-atrial (SA) node, which is situated in the wall of the right atrium, near the opening of the superior vena cava. SA node is broader at the top and tapering below and made up of thin fibres SA node acts as the ‘pacemaker. of the heart because it is capable of initiating impulse which can stimulate the heart muscles to contract. The impulse spreads as a wave of contraction over the right and left atrial wall, pushing the blood, through the atrioventricular valves into the ventricles and the same wave from SA node reaches the atrioventricular node (AV), to emit an impulse of contraction, spreading to the ventricular muscle, through the atrioventricular bundle and the Purkinje fibres.
The expansion of the artery every time, the blood is forced into the arteries, is called pulse. Normal pulse rate ranges from 70 - 90 / min.