2. The Heart When the bloodcirculatesin the body, in enters the heart through the right atrium, passes through to the right ventricle, and flows out through the pulmonary artery to the lungs-where it picks up oxygen and gets rid of carbon dioxide. From the lungs, blood returns to the left atrium and then enters the left ventricle where it is pumped to the body through the aorta.
5. Components of the Circulatory System Arteries:Arteries have thick, elastic muscular walls and carry blood under high pressure away from the heart. Veins: Veins have thin walls and valves that prevent the blood from flowing backwards. Veins carry blood to the heart from the rest of the body. Capillaries: Capillaries are the most numerous and smallest blood vessels. They carry materials such as oxygen and nutrients to the cells and remove wastes including carbon dioxide. Heart: The biological pump that circulates the blood around the body. The heart is a strong muscular organ that acts as a pump for the circulatory system. Blood: The blood carries nutrients such as glucose &wastes such as carbon dioxide. It helps to fight disease and to clot when there is a cut so the cut is sealed.
6. Main Components of Blood Plasma: Plasma is a straw-coloured liquid which mostly consists of water & nutrients such as glucose and waste products such as carbon dioxide are carried around the body in the plasma. Red Blood Cells: The job of red blood cells is to carry oxygen from the lungs to the rest of the body. White Blood Cells: White blood cells are large and have a nucleus. They have an irregular shape and are not rigid so they can squeeze into the small blood vessels. They fight disease and engulf germs while others produce chemicals called antibodies that attack germs. Platelets: Platelets help blood to clot if a blood vessel is cut. This seals up the cut so that germs cannot get in.
