Circulatory System · Animation

One red blood cell, one lap

A red blood cell travelling through the heart, lungs and body tissues A cutaway heart sits in the middle with four chambers: right atrium and right ventricle tinted blue on the left of the picture, left atrium and left ventricle tinted red on the right. Four valves open as the cell passes: tricuspid, pulmonary, mitral and aortic. The cell leaves the right ventricle through the pulmonary valve, travels the pulmonary artery to the left lung, picks up oxygen at an air sac, returns through the pulmonary vein into the left atrium, drops through the mitral valve into the left ventricle, and leaves through the aortic valve into the aorta, which arches over the top and down to the body. In the body tissues it drops off oxygen and picks up carbon dioxide, then returns through the vena cava to the right atrium. Pulmonary circuit Systemic circuit Right lung Left lung air sac Body tissues (muscle, organs, skin…) cells use O₂ and make CO₂ Rightatrium Rightventricle Leftatrium Leftventricle tricuspid mitral cutaway view · “right” and “left” are the patient's own sides pulmonary aortic Vena cava to the right atrium Pulmonary artery to the lungs Pulmonary vein to the left atrium Aortic arch Aorta largest artery Arteries → capillaries Capillaries → veins