Blood pressure is the force that moves blood through our circulatory system. It is an important force because oxygen and nutrients would not be pushed around our circulatory system to nourish tissues and organs without blood pressure. Blood pressure is also vital because it delivers white blood cells and antibodies for immunity, and hormones such as insulin. Just as important as providing oxygen and nutrients, the fresh blood that gets delivered is able to pick up the toxic waste products of metabolism, including the carbon dioxide we exhale with every breath, and the toxins we clear through our liver and kidneys. Blood itself carries a number of other properties, including its temperature. It also carries one of our defenses against tissue damage, the clotting platelets that prevent blood loss following injury.