Double circulatory human

1.	Double circulatory human
Answer» 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. So, it is called Double Circulation of blood.The double circulation of blood includes:(i) Systematic Circulation(ii) Pulmonary CirculationSystemic circulation: First stage of systemic circulation starts from left atrium to left ventricle. This transfers the oxygen rich blood to aorta for the supply to various parts of the body. Later, the veins and venules collect the blood from various parts of the body. This blood is rich in carbon dioxide than oxygen and is known as deoxygenated blood.Pulmonary circulation: The pulmonary artery collects the blood from right ventricle and passes to lungs for oxygenation. Lungs collects the deoxygenated blood supplied to it and purifies. Then the oxygenated blood is pumped back to left atrium of the heart through the pulmonary vein. Left atrium passes the blood to left ventricles where they pump the oxygenated blood to aorta for systemic circulation.

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