Draw a sectional view of human heart and label on it aorta, pulmonary vein, vena cava, left ventricle.

Question

(a) Draw a sectional view of human heart and label on it aorta, pulmonary vein, vena cava, left ventricle. 

(b) Why is double circulation of blood necessary in human being?

Answer 1

(a)

(b) The blood passes through the heart twice. Right side of the heart receives deoxygenated blood which is circulated to lungs for purification. At the same time the left side of the heart receives oxygenated blood which is circulated to the body. This is called double circulation.