In this article we will discuss about the Types and Significance of Double Blood Circulation.
Types of Double Blood Circulation:
There are two types of double blood circulation. They are follows:
(i) Systemic Circulation:
The flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from various body parts to the right atrium is called systemic circulation. All systemic arteries arise from the aorta. The bronchial arteries, which carry nutrients to the lungs, are also part of the systemic circulation.
After completing the circuit, all the veins of the systemic circulation bring deoxygenated blood into the superior vena cava, the inferior vena cava or the coronary sinus, which open into the right atrium (Fig. 18.20).
Because the systemic circulation supplies blood to most of the tissues of the body, it is also called the greater circulation or peripheral circulation. The purpose of systemic circulation is to carry oxygen and nutrients to body tissues and to remove carbon dioxide and other wastes from the tissues.
(ii) Pulmonary Circulation:
The flow of deoxygenated blood from the right ventricle to the lungs and the return of oxygenated blood from the lungs to the left atrium is called the pulmonary circulation.
The pulmonary trunk arises from the right ventricle and then divides into the right pulmonary artery and left pulmonary artery which supply deoxygenated blood to the right and left lungs respectively. Exchange of gases takes place in the lungs. Two pulmonary veins from each lung transport the oxygenated blood to the left atrium (Fig. 18.20).
Significance of Double Blood Circulation:
(i) It checks the mixing of oxygenated and deoxygenated blood,
(ii) Oxygenated blood carries more oxygen,
(iii) Deoxygenated blood carries more carbon dioxide for removal.