Describe the structure of the heart, relating to it's function.

The heart is divided into two halves - right and left. In each half there are two chambers - an atria and a ventricle, which are connected by a valve. The right atria receives deoxygenated blood from the body via the vena cava. When the right atria contracts, blood travels through the tricuspid valve to the right ventricle. From the right ventricle, blood travels through the pulmonary valve the lungs, via the pulmonary artery. The left atria receives oxygenated blood from the lungs via the pulmonary vein. Upon contraction, blood travels through the mitral valve to the left ventricle which pumps the blood through the aortic valve via the aorta to the organs.