1. The Human Immune System
Video

2. What is the immune system?
The body’s defense against disease causing organisms, malfunctioning cells, and foreign particles

3. The First Line of Defense
1. Skin (epidermis) forms a
shield against invaders.
2. Mucus: foreign particles
and bacteria stick
3. Cilia: Hair-like structures
sweep this mucus into the
throat for coughing or
swallowing (nose hairs)
4. Saliva: contains many
chemicals that break down
bacteria
5. Stomach Acid

4. The Second Line of Defense
1. White blood cells: attack if invaders get within the body
2. Phagocytes: cells that eat foreign particles
Video
3. T Cells (Natural Killer cells): attacks and kills infected cells
4. Inflammation: Injured body cells release chemicals called histamines

5. The Third Line of Defense ~Antibodies~
Most infections never make it past the first and second levels of defense
Antibody: made if infection past 1 and 2 level of defense (made by B-cells)
Video - 1:58

6. Active Immunity YOU produce the antibodies
You have already been exposed to the antigen - You had the disease (You fought it, you won, you remember it)
Vaccines- Injected the disease (You detected it, eliminated it, and remember it

7. Passive Immunity You don’t produce the antibodies
A mother will pass immunities on to her baby during pregnancy/breastfeeding