1. Innate Immunity

2. Immunity Body’s mechanisms to prevent and fight foreign invaders
Pathogens – anything that can cause disease – includes bacteria, viruses, parasites, toxins, etc.

3. Innate Immunity Innate = born with it, always present Non-specific
Does not improve after exposure

4. Physical Barriers Skin – Layers of epithelial cells
Contains sebaceous glands which secrete sebum (oil) which is slightly acidic to kill bacteria and other invaders
Hair – helps trap invaders
Sweat – high salt content kills many types of invaders

5. Mucous membranes – line areas inside the body that are directly exposed to things from the exterior environment (digestive tract, respiratory tract, urinary tract)
Mucous traps invaders

6. Chemical defenses
Acidity – low pH found on skin, mucous membranes, stomach acid, urine
Lysozymes – enzymes that break down bacterial cell walls, found in tears, saliva, sweat, mucus

7. Natural Bacteria Non-pathogenic
Out-compete pathogens – better at getting available space and nutrients so there’s not enough left over for invaders

8. Fever Relates to ideal temperatures for enzyme function
Pathogens replicate more slowly, immune cells work faster
Can be dangerous if it gets too high

9. Phagocytes
Specific types of white blood cells recognize, engulf, and destroy pathogens
Macrophages most common

10. Natural killer cells Destroy infected cells and cancerous cells
Release granules by exocytosis near the infected cell to kill them

11. Inflammation Response to tissue damage
Signs include pain, redness, heat, and swelling
Tissue damage causes a release of many chemical signals, including histamines, which triggers nearby capillaries to dilate, increasing blood supply to help deliver clotting factors and phagocytes