Capillaries are very tiny blood vessels — so small that a single red blood cell can barely fit through them. They help to connect your arteries and veins in addition to facilitating the exchange of ...

Lymphocytes are white blood cells that help the body fight infection and disease. The healthy range for an adult is between 1,000 and 4,800 lymphocytes per microliter (µL) of blood. Doctors will ...

Red blood cells are important mediators of the innate immune system. Depending on the cellular environment, these cells either activate the immune system or maintain the system in a dormant state. In ...

Blood is made up of plasma and solid components. Of these, the larger part is plasma, comprising about 55%. It appears as a straw-colored fluid and is composed mainly of water, but also carries ...

The cardiovascular system consists of the heart, blood vessels, and blood. Its primary function is to transport nutrients and oxygen-rich blood to all parts of the body and to carry deoxygenated blood ...