The Human Heart

The red connections signify oxygenated blood and the blue connections signify deoxygenated blood. So deoxygenated blood is pumped from either the top or bottom of your body through your right atrium into your right ventricle from where it travels to the lungs to pick up oxygen. Once it has picked up oxygen from the capillaries in the alveoli it travels into your left atrium; through your left ventricle which transports it to the rest of your body where deoxygenated blood is picked up and the process starts all over again.