b'Anatomy of a HeartbeatChapter hapterYour heart is made up of two muscular pumps that circulate blood around the body.The right atrium and ventricle receives de-oxygenated blood from the veins,pumps the blood to the lungs where oxygen is added and carbon dioxide lost and thengoes back to the left side of the heart.The left atrium and ventricle then pumps the oxygenated blood via the aorta tothe rest of the body.2. Fresh,3. Inlet valves close 1. Old blood - ready4. The heart muscle oxygen-rich bloodand the blood to be pumped tofrom the lungs entersflows into thecontracts and the the lungs to receivethe left side of thelower chambers. outlet valves open, oxygen; enters theheart. pumping the old right side of the heart. blood to the lungs and the fresh blood around the body.Blood ComponentsPlatelets PlasmaIf an injury occurs, plateletsPlasma consists of water, (the smallest blood cells), helpnutrients, salts, hormones and to stop bleeding by pluggingproteins, including dissolved the broken blood-vessel wallprotein fibrinogen, which plays and releasing chemicals thata key role in blood clotting.promote clotting.White Blood Cells Red Blood CellsThere are five main typesThese pigmented cells give the of white blood cells. Theyblood its colour. They have a all play various roles butlarge surface area to absorb mostly fight against andoxygen from the lungs, but help destroy infection. are flexible enough to squeeze through small blood vessels.How Your Body Works 25How Your Body Works25'