Innate defenses(first line of defense, surface barrier
Tight Junctions
keep bacteria from entering between cells
Keratin
Make skin tough
Sebum
slightly acidic denters growth of most pathogenic organisms
Mucus
In nasal passages and bronchi trap pathogens and other debris
Hydrochloric acid
in stomach destroyed ingested pathogens
Normal Flora
of the skin, mouth, and gut, are good bacteria which provide competition for bad bacteria