Question

Describe double circulation in human beings.

Hint:

- Double circulation ensures that the oxygenated and deoxygenated blood never mix, allowing efficient oxygen delivery and waste removal. - The heart plays a central role in maintaining the separate circulations of the body and lungs.

Answer 1

Double circulation refers to the two separate circuits through which blood circulates in the human body. It involves two distinct loops: the pulmonary circulation and the systemic circulation.
1. Pulmonary Circulation:
Pulmonary circulation is the flow of blood from the heart to the lungs and back to the heart. It helps in the exchange of gases (oxygen and carbon dioxide).

Deoxygenated blood from the body flows into the right atrium of the heart.
From the right atrium, the blood moves into the right ventricle.
The right ventricle pumps the deoxygenated blood through the pulmonary artery to the lungs.
In the lungs, the blood releases carbon dioxide and picks up oxygen.
The oxygenated blood then returns to the left atrium of the heart through the pulmonary veins.

2. Systemic Circulation:
Systemic circulation is the flow of oxygenated blood from the heart to the rest of the body and back.

Oxygenated blood from the left atrium passes into the left ventricle.
The left ventricle pumps the oxygenated blood through the aorta to all parts of the body.
The oxygen and nutrients are delivered to the body’s cells, and waste products like carbon dioxide are collected.
The deoxygenated blood then returns to the right atrium of the heart through the superior and inferior vena cava.

Importance of Double Circulation:
- Double circulation ensures that oxygenated blood is delivered efficiently to body tissues, while deoxygenated blood is sent to the lungs for gas exchange.
- It maintains a high pressure in the systemic circulation, allowing effective nutrient and oxygen distribution, while the pulmonary circulation operates at a lower pressure, preventing damage to the lungs.