Now that we've talked about your blood vessels, we're going to zoom in a little closer and talk about your blood itself. We'll start by outlining the basic components of blood -- including erythrocytes, leukocytes, platelets, and plasma -- as well as the basic process of hemostasis that stops bleeding, and how antigens are responsible for the blood type that you have. By the end of this episode, you should be totally prepared for your next blood drive. [10:00]