Question

Describe double circulation of blood in human beings.Why is it necessary?

Answer 1

The human heart comprises four chambers: the right atrium, right ventricle, left atrium, and left ventricle.
Blood Circulation Through the Heart:
De-oxygenated blood from the body's upper and lower regions is transported to the heart's right atrium via the superior and inferior vena cava, respectively.


1. The right atrium contracts, moving de-oxygenated blood to the right ventricle through an atrioventricular valve.

2. The right ventricle then contracts, pumping deoxygenated blood into the pulmonary arteries. These arteries direct the blood to the lungs for oxygenation. Pulmonary veins return the oxygenated blood from the lungs to the left atrium.

3. The left atrium contracts, and through the atrioventricular valve, oxygenated blood enters the left ventricle. From the left ventricle, blood is propelled into the aorta.

4. The aorta branches into numerous arteries that distribute oxygenated blood to all bodily regions.


Schematic Diagram of Blood Circulation in Humans:

This process results in blood passing through the heart twice, a phenomenon known as double circulation.
Significance of Double Circulation:
The separation of oxygenated and de-oxygenated blood ensures an efficient oxygen supply to the body's cells. This efficient oxygen delivery system is crucial for warm-blooded animals, including humans. Warm-blooded animals must regulate their body temperature, requiring a higher metabolic rate and thus more oxygen for respiration to generate sufficient energy. Consequently, the human circulatory system's efficiency is enhanced by the double circulatory heart.