Chapter 43- Defense against disease

Chapter 43- Defense against disease - Chapter 43 Defense...

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Chapter 43 Defense against Disease The Immune System 3 lines of defense against microbial attack Innate defenses: 1. External barriers A. Skin - physical barrier to microbial entry Physical barrier- inhospitable environment for growth; dry, dead cells at surface. Sweat/sebaceous glands secreting acids and natural antibodies like lactic acid. Most bacteria cannot harm you. B. Mucous membranes of respiratory and digestive tracts well-defined. Secretions have antibacterial enzymes C. Stomach; if microbes swallowed, acids and protein-digestive enzymes destroy them. In your body but hasn’t gained access to your tissues 2. Nonspecific internal defense- A. Phagocytic cells : white blood cells (WBC) in extracellular fluid, amoeboid shape, destroy microbes by phagocytosis. White blood cells are made in your bone marrow B. Natural Killer cells: white blood cells that destroy body cells infected by viruses and cancerous cells by punching HOLES in them. If infected, your body will kill them with the natural killer cells. It contacts infected cell, releases pore-forming proteins… secretes the pore forming proteins through exocytosis. C. Inflammatory response- caused by large-scale microbial invasion through wound. Example of this is mosquito bite. Allergies are an example of inflammatory response gone bad. - Histamine released by da m aged cells - Histamine increases blood flow and “washes” out wound—can change the blood flow and per m e ability of the capillaries. Cleans up the m ess caused during the injury - Where there is excess hista mine, there is inflam m ation (red, - When cells are da m ag ed upon injury, lots of tissue and cells are - Other che micals- m acrophages (WBC engulf bacteria, dirt, tissue debris). When white blood cells com e out of the wound is called
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- There are 50,000 miles of capillaries in your body. - Blood clotting “walls off” wounded area - Figure 43.8 D. Fever- response to microbes establishing major infection. Low grade  (100-102 F) fevers beneficial. When exposed to a cold, you are  exposed to a low grade fever for a day or two. - Slows down microbial reproduction - Enhances immune system Acquired Immunity 3. Specific Immune Response- reaction to specific type of microbe and  provides future protection. Involves 2 types of WBC called  A. They are the B cells (bone) and T cells (thymus) - Blood is mostly plasma - All of blood cells are formed in bone marrow…if they mature in  bone marrow they are called B cells. If they move to the  thalamus, they are called T cells. Each one of these can break  - Mast cells- connective tissue that releases histamine; important  in the inflammatory response - Neutrophils- white blood cells that engulf invading microbes - Cytokinesis- cells split - Step 1 - recognize the invader-  o 1.    Antibodies  (protein produced by a host to bind to and inactivate foreign particles) --- 
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This note was uploaded on 02/05/2011 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Chapter 43- Defense against disease - Chapter 43 Defense...

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