COMPONENTS OF BLOOD

The average person has about 11 pints (5 liters) of blood, which consists of cells and fluid (plasma). Red blood cells, the most numerous blood cells, transport oxygen in the…

THE LYMPHATIC SYSTEM

A network of lymph vessels, lymphatic tissue, and clumps of bean-shaped lymph nodes (glands) makes up the lymphatic system. The lymph vessels collect fluid (lymph) from the body tissues and…

THE BODY’S DEFENSES

Several barriers and responses work together to protect the body against infection and the development of cancer. Physical and chemical barriers and the inflammatory response form the first two lines…