The normal heart reviewed
The heart is a pump consisting of four chambers. Its job is to pump blood which has already been around the body, to the lungs to obtain oxygen, and then back around the body to supply the organs. The two chambers at the top are the left and right atria, sometimes known as the receiving chambers as they act as reservoirs for their respective ventricles. The two chambers at the bottom are the left and right ventricles, sometimes known as the pumping chambers as they are responsible for pumping the blood to the body and the lungs. A valve links the top and bottom chambers on each side, the mitral valve on the left side and the tricuspid valve on the right side, and the wall between the left and right sides of the heart is called the septum (central heart wall). Blood returning from the body enters the right atrium by way of the superior and inferior vena cava, from where it passes to the right ventricle via the tricuspid valve. When the heart muscle contracts, the tricuspid valve closes, and the pressure in the right ventricle rises and forces open the pulmonary valve allowing blood to enter the lungs via the pulmonary artery. The main arteries of the lungs branch into very many smaller vessels (much like the structure of a tree: trunk, branches, twigs), with much thinner walls which are able to take oxygen from the air in the airways of the lungs into the blood stream. The oxygenated blood then returns from the lungs in the four read more
