Final answer:
The time between two successive heart beats is referred to as the cardiac cycle, consisting of a systole and diastole. The cycle begins with the atria contracting and ends with the ventricles relaxing, ensuring efficient blood pumping. The period per beat can be calculated if the heart rate is known.
Step-by-step explanation:
The period of time between two successive heart beats is known as the cardiac cycle, which includes phases of contraction and relaxation termed systole and diastole respectively. During the cardiac cycle, the heart chambers go through these phases in a coordinated manner to efficiently pump blood.
Initially, the contractile phase called atrial systole happens. This is followed by ventricular systole when blood is pumped out. Afterward, the ventricles and atria enter the relaxation phase, known as diastole, where the heart fills with blood, completing the cycle.
A typical cardiac cycle is composed of both the atrial and ventricular systole and diastole. The heart's pacemaker cells, located in the sinoatrial node, initiate the cardiac cycle by creating electrical signals, ensuring that the atria and ventricles contract in a coordinated fashion.
If the heart rate is known, such as 150 beats per minute during exercise, the time per beat in seconds can be calculated. To illustrate, for a heart rate of 150 beats per minute, the period comes out to be 0.4 seconds per beat (60 seconds/150 beats).