Double Circulation

In human beings, the blood goes through the heart twice during each cycle i.e. the blood passes through the human heart two times to supply once to the whole body This type of circulation is called Double Circulation of blood.

Double Circulation has two components

Pulmonary circulation

Systemic circulation.

Also Check – Double Circulation -Definition, 2 Loops, Flowchart,Types, Importance

Also check – Transportation in Human Beings

Pulmonary circulation

• It is the movement of blood from the heart to the lungs and back.
• Deoxygenated blood of the body enters the right auricle, passes into the right ventricle which pumps it into the pulmonary arch. 
• With the help of two separate pulmonary arteries the blood passes into the lungs. Here the arteries break up into arterioles and then capillaries for oxygenation.
• Oxygenated blood comes back to the left atrium of the heart through pulmonary veins.

Systemic Circulation

•  It is the circulation of blood between the heart and different parts of the body except lungs. 
• Oxygenated blood received by the left atrium passes into the left ventricle. 
• The left ventricle pumps it into the aorta for supply to different body parts. 
• Inside the organs the arteries break up into arterioles and then capillaries.
• Capillaries provide oxygen and nutrients to tissues. They receive carbon dioxide and wastes from the tissues.
• Capillaries unite to form venules which join to produce veins. Veins take the deoxygenated blood to the heart but now into the right Auricle.

Also Check – Describe the Flow of Blood through the Heart of Human Beings

Also Check – Difference between Double Circulation and Single Circulation

Advantages of Double Circulation

4 Important Reasons for Why Double Circulation is necessary for Human Beings –

1. Double circulation is made possible by the heart being divided into two by the septum.
2. This helps Oxygenated blood be separated from deoxygenated blood. The separation of oxygenated blood and deoxy-genated blood allows a more efficient supply of O₂ to the cells.
3. By having a double circulation, the heart can increase the pressure of the blood after it has passed through the lungs. In other words, the systemic circulation carries blood at higher pressure than the pulmonary circulation. This allows for a more rapid circulation of blood to body tissues without damaging the delicate capillaries in the lungs
4. Blood entering lungs is at low pressure compared to blood leaving. This ensures that blood flows slowly in the lungs allowing more time for blood to be well oxygenated.