The left ventricle of the heart pumps oxygenated to the organs of the body. The ventricular septum keeps the left and right ventricles separate. The left ventricle is the more muscular of the two ventricles.
Oxygenated blood from the lungs enters the right atrium. A contraction from the left atrium sends this oxygenated blood through the mitral valve into the left atrium. The mitral valve closes so that blood does not seep back into the left atrium when the left ventricle contracts.
Left ventricle contraction pushes blood into the aorta, the largest artery into the body. From the aorta, several smaller constituent arteries arise, and these arteries bring blood to nourish the different parts of the body.