Human Defense System
Innate Defenses
Physical Barriers
- Skin prevents germs, parasites, and other harmful substances from getting inside
- We have openings in the body such as digestive, reproductive, sensory organs and respiratory openings
- The openings are covered by mucous membranes which contain enzymes that break down the bacteria.
- Mucous traps bacteria and small particles
- Mucous is also considered human cough reflec, cornea of the eye, ear wax, stomach acid and skin oils
Phagocytes
- Cells that have the ability to ingest and sometimes digest Yucky stuff like bacteria, dust, carbon
- Eats foreign objects
FEVER
- 1. A fever stimulates your immune system into producing more white blood cells, antibodies, and a protein called interferon, all of which work to protect your body against harmful microorganisms.
- Also a fever helps to send iron to your liver so that it is not readily available to fuel the growth of invading bacteria.
Inflammation
- Inflammation
- Pathogens enter wound
- Platelets release blood clotting proteins
- Injured tissues and macrophages release cytokines to recruit help
- Changes in capillary wall structure allow interstitial fluid and WBC's to leak out in tissue
- Stimulate bone marrow to make and release additional nutrinophils and macrophages
- Attract other immune system cells to the cite
- Activate cells involved in tissue repair and wound healing
- Induce fever
- Mast cells release factors that constrict blood vessels at wound and dilate vessels nearby
- Neutrophils arrive and begin phagocytizing pathogens
- Leukocytes arrive and mature into macrophages
Natural killer cells
- Type of lymphocyte
- They control microbial infections and tumors from spreading far
Complement
- Number of small protiens found in the blood
- The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear pathogens from an organism