Question

Explain the following terms-

1. Systole and diastole
2. Pulse
3. Blood pressure
4. Systemic circulation
5. Single circulation

Answer 1

a. Systole and Diastole

The complete set of events within a heart from the beginning of one heartbeat to the beginning of the next heartbeat is called the cardiac cycle. A cardiac cycle is best explained in two terms systole and diastole.

Systole means the contraction of heart chambers to pump blood out. Diastole implies the relaxation of the heart chambers between two contractions.

b. Pulse

The rhythmic throbbing of the arterial wall due to the pressure exerted by the blood in them is called a pulse. It occurs as a result of the regular rhythmic contraction and relaxation of the heart chamber.

c. Blood pressure

It is the pressure exerted by the blood against the wall of arteries. Blood pressure is measured in two parts- systolic and diastolic. In humans, the normal blood pressure ranges from 120-140/70-80 mm of Hg.

d. Systemic circulation

Double circulation, i.e., the circle in which blood passes through the heart twice in one complete cycle, has two parts- Systemic circulation and Pulmonary circulation.

The blood circulation between the heart and various body parts is known as systemic circulation. The pathway of which can be given as follows:

$\mathrm{Left}\mathrm{ventricle}\stackrel{\mathrm{Oxygenated}\mathrm{blood}}{\to }\mathrm{Aorta}\stackrel{\mathrm{Oxygenated}\mathrm{blood}}{\to }\mathrm{Arteries}\stackrel{\mathrm{Oxygenated}\mathrm{blood}}{\to }\mathrm{Body}\mathrm{Parts}/\mathrm{Tissues}\stackrel{\mathrm{Deoxygenated}\mathrm{blood}}{\to }\mathrm{Veins}\stackrel{\mathrm{Deoxygenated}\mathrm{blood}}{\to }\mathrm{Vena}\mathrm{cava}\stackrel{\mathrm{Deoxygenated}\mathrm{blood}}{\to }\mathrm{Right}\mathrm{atrium}$

e. Single circulation

Single circulation is the circulatory system in which blood passes through the heart only once in a complete cycle. This type of circulation is typically found in Fish.