Question

Write a note on the working of the human heart.

Answer 1

Hint: The heart is a major part of the circulatory system. The main function of the heart is to pump oxygenated blood to all parts of the body through arteries. Humans have a four chambered heart-two upper chambers (the atria) and two lower ones (the ventricles).

Complete answer:
The heart is present between the lungs in the thoracic cavity. The heart has 2 layers of covering known as the pericardium, which is protective in function. The human heart has a major role in pumping oxygenated blood to all parts of the body. It meanwhile contracts and relaxes rhythmically.

There are two types of blood vessels associated with the heart i.e. artery and veins. The heart is supplying oxygen and nutrients to the tissues and removing wastes from the body. The heart is made up of four chambers consisting of two atria (left and right) and two ventricles (left and right) which contract and relaxes alternatively to pump the blood. These 4 chambers are connected with each other by means of four valves- tricuspid, pulmonic, mitral, and aortic valves. These valves allow unidirectional flows of blood and prevent the backflow of blood.

Blood enters through two large veins, inferior and superior vena cava, and then flows from the right atrium to right ventricles through tricuspid valves. The blood leaves the right ventricles and then flows into the lungs through the pulmonary artery. In the lungs, the blood gets oxygenated and returns to the heart via the pulmonary vein into the left atrium. Then the blood passes to the left ventricles through mitral valves. The blood leaves the heart through the aortic valve to the aorta and body.

Note: The arteries carry oxygenated blood away from the heart (except pulmonary artery which carries deoxygenated blood) to all the parts of the body. The aorta is the largest artery. The veins carry deoxygenated blood towards the heart from all parts of the body(except pulmonary vein).