Question

Give appropriate biological or technical terms for the following:
The relaxation phase of the heart.

Answer 1

Hint: The sequence of alternating contraction and relaxation of the atria and ventricles in order to pump blood throughout the body with the help of the heart is termed as the cardiac cycle. Each cardiac cycle has a diastolic phase and a systolic phase. Both the atria and ventricles undergo alternating states of systole and diastole in the cardiac cycle.

Complete answer:
The heart is about a fist-sized muscular organ. It is located just behind and slightly to that of the breastbone. Heart pumps blood through a series of networks of arteries and veins known as the cardiovascular system and is the most important organ in animals.
In simple words, the performance of the human heart from the beginning of one heartbeat to the beginning of the next is known as the cardiac cycle. When the heart begins to contract, the cardiac cycle begins as early as \[{4^{th}}\] gestation weeks.
The two cardiac cycle phases are systematic and diastolic. The diastolic phase or the called diastole is when the heart chamber is in a state of relaxation and fills with blood which is received from the veins. The systolic phase or systole is when the heart chambers are contracting and pumps the blood towards the periphery through the arteries.

Hence the relaxation phase of the heart is termed as diastole.

Note:
Throughout most of the period of diastole, blood passively flows from left atrium and right atrium into the left ventricle and right ventricle. The aortic and pulmonic valves open to permit ejection into the aorta and pulmonary artery during systolic phase. During systole, the atrioventricular valves are closed and therefore no blood enters the ventricle.