 Nonspecific immunity No specific target; treats all foreign substances the same  Specific immunity Treats each microbe differently

Nonspecific body defenses: A. surface protection (1 st line of defense) 1. Skin Prevents entry 2. Mucous membranes Ex: Mucus, gastric juice, cilia, nasal hair, tears, saliva

 These barriers try to stop all pathogens therefore they are considered non- specific defences. The physical barriers of our general defence system consist of:  · The Skin- It is a physical barrier that stops pathogens.  · Clotting- If the skin is broken the blood clot stops entry of pathogens.  · Sebaceous and sweat glands- These produce chemicals that kill bacteria.  · Lysozyme- This is in the saliva and the tear glands. It kills bacteria.  · Mucous membranes- These secrete mucus which lines many body parts. The mucous traps pathogens and prevents them from entering the body.  · Nasal hairs- These remove suspended micro-organisms from the air.  · Cilia- These small hairs beat to force mucus to the pharynx for swallowing to the stomach. Coughing helps in this process.  · Hydrochloric acid- This is found in the stomach. It kills micro- organisms.  · The vagina- It contains bacteria that produce lactic acid that prevents the growth of pathogens. Also the vagina has a low pH to kill bacteria as well as mucous membranes. DON’T WRITE

Nonspecific body defenses: B. Internal defense 1. Phagocytes  Engulfs a foreign particle/microbe  Cytoplasm pulls it into vacuole. Binds with lysosome

2. Natural killer cells  Releases chemicals onto target’s cell membrane to destroy it.

3. Fever Temperature (in hypothalamus) reset by pyrogens (chemicals secreted by WBCs exposed to foreign substance) + increases speed of repair, kill microbes - denature enzymes if too high

4. Inflammatory response kill microbe/prevent spread/tissue repair Vasodilation  red, heat  Brings nutrients in blood to injured site Increased permeability of capillaries  swell 4 cardinal signs of inflammation:  Redness, heat, swelling, pain