The Immune System

The Immune System is also called the Lymphatic System

The Lymph System

Lymph - colorless fluid that circulates throughout the body

Lymphatic Organs - containing large numbers of lymphocytes (thymus, tonsils, spleen)

Red Bone Marrow, Thymus Gland, Lymph Nodes , Spleen, Tonsils


Nonspecific - barriers to entry (skin), inflammatory response, phagocytes

Specific - require B Lymphocytes and T lymphocytes (B cells and T cells)

Typical Immune Response

1. Foreign substance invades the body
2. Macrophages consume cells and present anigens (APC = antigen presenting cell)
3. Macrophages activate Helper T cells
4. Helper T cells active B cells (to make antibodies) and Killer T cells

immune response

See Animation: The Immune Response

How Do Vaccines Work?

Vaccines contained a killed or weakened part of a virus (or other pathogen) to stimulate your immune system to react to the antigen. Once you have antibodies for that microbe, the real one will not make you sick.

Do you remember who invented the first vaccine?
Why do some people not want to vaccinate their children?
Why do some people choose not to get the flu vaccine?