... of four chambers which are divided by the vertical septum. The upper chambers are the left and right atria, the lower chambers are the left and right ventricles there is a one-way valve system which means that the blood only travels in one way. (Snell 2000). With each contraction, or heartbeat the heart pumps blood forwards in to the arteries. The arteries divide off into smaller branches to supply a network of capillaries, taking the blood to every part of the body. The veins collect the blood from the capillaries, and the branches of the veins join to larger veins which deliver the blood back to the heart. The blood from the veins fill the heart as it relaxes during the interval between each contraction. The right side of the heart receives blood from the body and pumps it through the pulmonary artery to the lungs. There it picks up fresh ...

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