Without a pump or water tank, no water will flow. Hosepipe properties also affect water pressure. Similar principles apply for blood flow.
Blood pressure is the force that moves blood through our circulatory system.
It is an important force because oxygen and nutrients will not push 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 delivers 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.
But what exactly is it that causes blood to exert a pressure in our arteries? Part of the answer is simple – the heart creates blood pressure by forcing out blood when it contracts with every heartbeat. Blood pressure, however, cannot be created solely by the pumping heart.