5.- The Immune System - General System Function

General System Function:

Its main function is to protect against disease and prevent infection. The immune system attacks organisms and substances that invade the body's systems and cause disease.
This consists of a network of cells, tissues and organs that work to protect the body. There are two types of white blood cells:

- Phagocytes: These are cells that destroy invading organisms.

- Lymphocytes: Are cells that allow the body to know that organisms are invaders

Webgraphy:

http://www.livescience.com/26579-immune-system.html

http://kidshealth.org/es/parents/immune-esp.html?WT.ac=pairedLink