Innate Immunity Immunity Bodys mechanisms to prevent and
Innate Immunity
Immunity • Body’s mechanisms to prevent and fight foreign invaders • Pathogens – anything that can cause disease – includes bacteria, viruses, parasites, toxins, etc.
Innate Immunity • Innate = born with it, always present • Non-specific • Does not improve after exposure
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
• 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
Chemical defenses • Acidity – low p. H found on skin, mucous membranes, stomach acid, urine • Lysozymes – enzymes that break down bacterial cell walls, found in tears, saliva, sweat, mucus
Natural Bacteria • Non-pathogenic • Out-compete pathogens – better at getting available space and nutrients so there’s not enough left over for invaders
Fever • Relates to ideal temperatures for enzyme function • Pathogens replicate more slowly, immune cells work faster • Can be dangerous if it gets too high
Phagocytes • Specific types of white blood cells recognize, engulf, and destroy pathogens • Macrophages most common https: //www. youtub e. com/watch? v=r. PLf n. ZHc. ICA
Natural killer cells • Destroy infected cells and cancerous cells • Release granules by exocytosis near the infected cell to kill them
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
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