Blood, Sweat and Tears Also, mucus, stomach acids, skin, nasal secretions, and saliva

Defense Against Disease Your immune system provides defense against bacteria, viruses and infectious parasites. Some of the same mechanisms are involved in detecting and destroying cancer cells. However, your own immune system can cause the symptoms of many infectious diseases--even death.

Blood cells are made in the Bone Marrow Red Blood Cells Phagocytes (eating cells) These engulf bacteria, viruses, dead cells and even cancer cells Lymphocytes (circulate in the blood; includes B cells and T cells)

What happens when you are injured? Go to “Anatomy of a Splinter” at “OUCH” on the Cells Alive Web Site.

The Inflammatory Response Mast cells sense the injury. That causes them to release histamine. (a chemical signal) Histamine induces mobilization of cell defenses.

Effects of Histamine Blood vessels dilate and become leaky. Blood flow increases. Fluid and macrophages leak out into the affected tissues

Phagocytes consume bacteria and cell debris and the tissue heals.

Symptoms of Inflammation Heat Swelling Redness Pain

Pus = dead white cells and fluid leaked out from the blood vessels to the tissues.

Generalized Inflammatory Response (flu-like symptoms) Fever Runny nose Body aches Nausea Swollen lymph nodes