Heart is the most important organ for the living organisms.
It functions to pump blood throughout the whole body. However, having the same function in all the organisms, it works differently according to species. Mammals have dual heart action in which the blood is pumped to lungs and back, the other in which it is pumped to whole body and back.Humans have four chambers in their heart. These chambers are 2 atrium and 2 ventricles. And according to their locations, their names are- right atrium, right ventricle, left atrium and left ventricle.
Our body is comprises of many vessels for the transportations of the oxygen situated in blood throughout the body. There are 2 main vessels which helps the heart to perform its function, which are aorta and pulmonary artery. There are 4 valves in heart. The valve separating the right atrium with the right ventricle is tricuspid valve. The valve separating the left atrium with the left ventricle is called mitral or bicuspid valve.
The largest vessel in the body is aorta which is separated to left ventricle by aortic valve. And the pulmonary artery is separated with the left ventricle by pulmonary valve. Remember, all these valves are one way valves. Our body constantly needs energy to grow, repair, and build and to maintain other body functions. Oxygen is one of the major factor from which we get energy. The oxygen we breathe travels into our blood which is transported to whole body.
So, heart pumps blood which carries oxygen, and this blood is called oxygenated blood. When the blood does not carry oxygen, it is called deoxygenated blood.The oxygenated blood is formed by absorbing the oxygen from lungs and then enters the left atrium through pulmonary vein. The left atrium contracts to send the blood to left ventricle by opening of mitral or bicuspid valve. During the contraction of left atrium, the left ventricle relaxes to allow the blood enter in it.
And then the left ventricle contracts to send this oxygenated blood through the aortic valve which allows the travel of blood to all parts of the body except lungs. The vessel which takes blood to all the parts of the body are called arteries. When the blood reaches to all the parts, they becomes deoxygenated which are received by the large vessels called veins. Now the vein brings the deoxygenated blood to heart and enters to right atrium. The right atrium contracts allowing the deoxygenated blood enter into right ventricle by opening of the tricuspid valve.
The one way valve causes the contraction of the right ventricle which leads to pushing deoxygenated blood into pulmonary artery through pulmonary valve. The pulmonary artery carries the deoxygenated blood to the lungs for the oxygenation of the blood. The lungs oxygenates the blood by exchange of gases and releasing carbon dioxide out of the body and oxygenated blood flows back into the heart through pulmonary vein, and hence starts the circulatory cycle all over again. This one cycle is repeated on an average of 72 times in a minute.