Page 6 - Health & Physical edu- 8

are called atrium and the lower chambers are called ventricle. The inferior venacava
and superior venacava open from the right atrium. Similarly, the pulmonary veins
open from the left atrium. The Pulmonary artery begins from the right ventricle
and aorta begins from the left ventricle. Between right atrium and right ventricle,
there lies tricuspid valve. Similarly, between left atrium and left ventricle, there lies

bicuspid valve. The functions of the heart are as follows.

a. It circulates the pure blood to different parts of the body.

b. It sends the impure blood to the lungs in order to purify it.

c. It assists to circulate the oxygen and nutrients hormones to different parts of the
body.

d. It helps to maintain temperature by blood circulation.
Blood Vessels

The vessels through which the blood flows are called blood vessels. The blood that
is pumped by the heart reaches the cells through the blood vessels. The same blood
again returns to the heart through the blood vessels. Such types of blood vessels
are of three types. They are: arteries, veins and capillaries. Except the pulmonary
artery, in all other arteries the pure blood flows and it reaches different parts of
the body. The pulmonary artery leads the blood to the lungs for purification. The

arteries divide into innumerable capillaries. The capillaries reach the cells. The
blood takes the oxygen and nutrients to cells and it takes back carbon dioxide and
other toxic elements again to the heart. In this process, the capillaries integrate into
veins and through those veins, the blood moves to the heart. Through all the veins,
the deoxygenated blood circulates but through the pulmonary veins, oxygenated
blood circulates.

The Blood

The red-coloured liquid in our body is called the blood. In the body of an adult
person, the quantity of the blood is approximately five liters. The blood consists of
blood cells and plasma. The blood cells are formed in bone marrow. The blood cells
are of three types. They are: red blood cells, white blood cells, and platelets. The
function of the blood is to take the nutrients, oxygen to the cells and concentrate

2 Health & Physical Education, Class-8