There's a battle going on inside you, even when you're calm or asleep. This program illustrates how the human immune system protects against harmful invaders - the germs and bacteria we encounter on a daily basis. Explains the function of first-line defenses and white blood cells, the distinction between viruses and bacteria, and the different functions of vaccines and penicillin. Also shows what happens when the immune system falters or fails, and how scientific understanding of the subject is increasing. Use this video to highlight a dimension of human anatomy that healthy people too often take for granted.

*A viewable/printable teacher's guide is available