Presentation on theme: " Nonspecific immunity No specific target; treats all foreign substances the same Specific immunity Treats each microbe differently."— Presentation transcript:
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