what the circulatory system does?

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the blood vessels of the ciculatory system are lifeline for the body's cell. the cell would starve to death without the food and oxygen brought to them by the flowing blood,and the cell could be poisoned if the blood did not carry away their waste products. digested food materials pass into the capillaries around the intestines and then are transported to all parts of the body. oxygen from the air breathed into the lungs passes into the blood vessels surrounding the lung's tiny air sacs. carbon dioxide and other waste gases pass from the blood into the air sacs and are sent out of the body with the next exhaled breath. the circulatory system also carries waste products from the body cells to the kidneys. there the wastes pass out of the blood through thin capillary walls and start their one way trip out of the body in the urine. foods,oxygen and wastes are not the only things carried in the blood. complicated chemicals called hormones act as chemical messengers and help control and coordinate the activities of the body. other substances called enzymes direct chemical reactions. blood also contains a sort of chemical repair kit,which can form a solid clot to plug up a hole in a damaged blood vessel. special kinds of cells travel through the vessels of the circulatory system. some reb blood cells are like barges floating along in the bloodstream. they carry loads of oxygen or carbon dioxide,others, the white blood cells,are like migrants workers that travel the body's waterways to get to wherever they are needed. they are the body's defenders,which battles invading viruses and bacteria. they also clean up old,wornout cells,and they attack body cell that have changed and might torn into cancer cells. even the fluid part of the blood is important. it provides water for the body cells and alsomhelps absorb and carry away excess heat,keeping the body temperature even.