Question

Write notes on the working of the heart of the man with the help of a neat labelled diagram. Add a note on double circulation.

Answer 1

Humans have a four-chambered heart. There is contraction and relaxation of the muscles in the chambers of the heart which is responsible for the pumping of the blood to the parts of the body. The blood pumped by the right ventricle enters the pulmonary artery, whereas the left ventricle pumps blood into the aorta. The deoxygenated blood pumped into the pulmonary artery is passed onto the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. This pathway constitutes the pulmonary circulation. The oxygenated blood entering the aorta is carried by a network of arteries, arterioles and capillaries to the tissues from where the de-oxygenated blood is collected by a system of venules, veins and vena cava and emptied into the right atrium. This is the systemic circulation.

The type of blood circulation in humans is called as double circulation.These two processes pulmonary and systemic circulation are together called as double circulation. This process is necessary because the blood enters twice in the heart in a single cycle. The deoxygenated and the oxygenated blood does not get mixed and the circulation is maintained properly.