Question

Write about single circulation and double circulation

Answer 1

Answer:

The human circulatory system is a double circulatory system. It has two separate circuits and blood passes through the heart twice: the pulmonary circuit is between the heart and lungs. the systemic circuit is between the heart and the other organs.

Answer 2

Single circulation

Blood flows only once through the heart during one cycle of passage through the body.

Occurs only in fishes


Only venous blood passes through the heart

Less efficient as gill capillaries slow down the blood flow, hence the body receives blood at a low pressure which decreases the rate of oxygen supply to the cells.





Double circulation

Blood flows twice through the heart during one cycle of passage through the body.

Occurs in all other vertebrates other than fishes



Mixed or oxygenated or venous blood passes through the heart.


More efficient as blood flows at higher pressure especially in birds and mammals. This increases the rate of supply of food and oxygen to the cell and also rapid removal of wastes from them.