The cardiovascular system is the blood, heart and blood vessels. It requires a physiological temperature for proper activity. Physiologically, blood transports oxygen from the lungs to all the cells in the body.
Blood transports nutrients from the digestive organs to the cells in the body.
Blood transports waste products from cells to kidneys, lungs and sweat glands. Blood transports hormones from endocrine glands to target cells. Blood transports enzymes to specific cells. Blood regulates pH levels via buffers and amino acids. Because of the water content in blood, blood regulates the water content of cells primarily through dissolved sodium ion levels.