Question

(a) What is meant by human circulatory system? Name the organs of the circulatory system in humans.
(b) Draw a diagram of the human heart and label its parts.
(c) What is meant by the terms 'single circulation' and 'double circulation'?

Answer 1

(a) The organ system that is responsible for the transport of materials inside the human body is known as human circulatory system. In human beings, the organs of circulatory system are heart, arteries, veins and capillaries.

(b) Diagram of human heart:


(c) Single circulation: A circulatory system in which the blood passes through the heart only once in one complete cycle is known as single circulation. It is commonly seen in fishes.
Double circulation: A circulatory system in which the blood travels twice through the heart in one complete cycle is known as double circulation. It is commonly seen in amphibians, reptiles, birds and mammals.