The basics of blood pressure

Blood circulating through your body moves with a certain force -- that's your blood pressure. This force can be affected by how strongly the heart is pumping and by the size of the vessels the blood is moving through. Blood moves through large arteries into smaller vessels called arterioles, which can expand and contract. When they expand, blood pressure goes down. When they contract, blood pressure goes up. (The body has some very good reasons and complicated systems for doing this.)

By Karen Ravn

February 8, 2010