Question

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


NCERT Class X
Science - Science

Chapter_Life Processes

Answer 1

Double circulation system is usually found in complex organisms like us , humans.It has two parts - Pulmonary and Systemic.
Let's start from pulmonary circulation . The right ventricle pumps the deoxygenated blood into the lungs and it is returned in the left auricle. Simultaneously in systemic circulation , the left ventricle pumps blood to all parts of the body and returns back in the right auricle. Valves in heart check that the blood flows in one direction only. In this system, blood flows twice to complete a single cycle and is known as Double circulatory system. It is necessary for maintaining body temperature and collecting CO2 from cells and provising oxygen and energy to cells & tissues.

Answer 2

"In human beings, the blood passes through the human heart two times to supply once to the whole body. This is known as Double Circulation of blood."

There are different types of double circulation

1. Systematic Circulation
2. Pulmonary Circulation

Systematic Circulation

• Systemic circulation shifts oxygenated blood from the left ventricle to the capillaries in the tissue.
• The oxygen-rich blood goes through the aorta for distribution to various body parts.
• The veins afterwards absorb the deoxygenated blood, which contains carbon dioxide from different parts of the body.
• The deoxygenated blood is shifted back to the superior vena cava, and then onto the right atrium.
• The right atrium then transports the blood to the right ventricle for pulmonary circulation after getting the deoxygenated blood.

Pulmonary Circulation

• The distribution of blood begins in the pulmonary circulation from the right atrium to the left atrium.
• The pulmonary artery gets the blood from the right ventricle and carries it to the lungs for oxygenation.
• When this oxygenated blood is pumped back to the left atrium through the pulmonary vein, it is brought to the left ventricles after the purification process.
• It is important for a human being to separate oxygenated and de-oxygenated blood as this makes their circulatory system more efficient and maintains constant body temperature.

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