S4 teaching practice ppt 2

1. How the heart
works
PRESENTED BY,
ANCY.A.R
NATURAL SCIENCE
CHRIST NAGAR COLLEGE OF EDUCATION

2. The heart actually consists of two
pumps working together-one on the
left side and one on the right.
The two atria contract first, pushing
blood into the two ventricles.
The atria then relax and the ventricles
contract to push blood into blood
vessels.

3. The Heart
Figure 8.8

4. Large veins carry deoxygenated blood from different
parts of the body to the right atrium of the heart,
which relaxes to receive the blood.
The right atrium then contracts and pours this blood
into the right ventricle, which relaxes to receive it.
 The right ventricle contracts and pours deoxygenated
blood into the pulmonary arteries, which carry it to
the lungs.
Exchange of gases takes place in the lungs and oxygen-
rich blood is sent back to the left side of the heart.

5. The left atrium relaxes to receive oxygenated blood
from the pulmonary veins, which bring blood from the
lungs.
The left atrium then contracts and pours oxygenated
blood into the left ventricle, which relaxes to receive it.
The left ventricle then contracts and pours oxygenated
blood into the aorta, which is the largest artery in the
body.
The aorta branches into arteries that supply oxygenated
blood to all the cells in the body.

6. There are valves between the atrium and
ventricle , and between the ventricle and
artery, on both sides of the heart .
They ensures that blood flows only from
the atrium to the ventricle and from the
ventricle into the artery, and not in the
opposite direction.

7. Circulation Through Human
Heart
Body blood enters RIGHT SIDE of HEART
Right atrium ----> right ventricle ----> Pulmonary artery
----> alveoli in lungs----> oxygenated blood --> Pulmonary
Veins ---->
Left Atrium. ----> Left Ventricle ----> blood leaves through
Aorta (first artery) ---> flows to body