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Body Defenses

Body Defenses. Chapter 15 Page 279. Agglutinins Antibodies Antigens Antitoxins Erythrocytes Exotoxin Escheriachia coli hemolysin. Incubation period Inflammation Leukocytes Lyse Lysosome Opsonins Phagocytosis Precipitins. Vocabulary. Three main defenses.

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Body Defenses

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  1. Body Defenses Chapter 15 Page 279

  2. Agglutinins Antibodies Antigens Antitoxins Erythrocytes Exotoxin Escheriachia coli hemolysin Incubation period Inflammation Leukocytes Lyse Lysosome Opsonins Phagocytosis Precipitins Vocabulary

  3. Three main defenses • The skin and mucous membrane • Circulatory defenses • Antibodies (immune response)

  4. Skin and Mucous Membrane • Skin • Mucous Membrane • Respiratory tract • Digestive tract • Genitourinary tract

  5. Skin and Mucous Membrane • The skin kills or inhibits bacterial growth through its secretions • Lactic acid from the sweat glands and fatty acids from the sebaceous (fat) glands and the low pH environment that they produce fight off many pathogens

  6. Respiratory Tract • The mucous membranes and the cilia filter and trap inhaled dust and pathogens • Coughing, sneezing, swallowing eliminate bacteria from the body • Lysozyme enzyme found in nasal secretions, saliva, and tears lyses certain gram-positive bacteria

  7. Digestive Tract • Pathogens are destroyed by digestive juices, the acidity of the stomach, and the alkalinity of the intestines • Not all bacteria are harmful • Escherichia coli (aides in production of Vitamin K) • Enterobacteraerogenes

  8. Genitourinary Tract • Flushes out pathogens by frequent urination and vaginal mucosal secretions • Birth control pills and antibiotics can kill normal vaginal flora and cause risk of infection

  9. Circulatory Defenses • If pathogens break through the first line of defense, the other defenses move in to destroy them • Phagocytes • Antibodies • Interferon

  10. Phagocytes • Phagocytes are cells of the reticuloendothelial system • Capable of phagocytosis • Fixed • Mobile

  11. Phagocytosis – amoeboid-like movement of white blood cells to approach, surround, and engulf foreign material • Necessary to remove dead blood cells, pathogens, and dust particles

  12. Phagocytes • Fixed • Attached firmly to liver, spleen, bone marrow, and lymph nodes, linings of intestines and blood vessels (reticuloendothelial system) • Mobile • “wandering phagocytes” leukocytes or white blood cells, they migrate to injured site

  13. Antibodies • If pathogens break through the first and second line of defense, antibodies take over

  14. Antibodies • Incubation period = time of the foreign antigen invading the body and the onset of the disease

  15. Antibodies • Antigens = Pathogens that stimulate the production of antibodies in the blood and the lymph

  16. Antibodies • Complement = special proteins that circulate in the liquid portion of the blood in an inactive form until needed

  17. Antibodies • Antitoxins- neutralize toxins • Agglutinins- cause bacteria clump together • Lysins- cause the bacteria to dissolve • Opsonins- make them more readily prey to be ingested by phagocytes • Precipitins- cause bacteria to settle out of the bloodstream so threat they can filtered out and destroyed

  18. Infection • Local infection • Restricted to one area • General infection • One that has spread to many parts of the body • Recognized by finding bacteria in the bloodstream

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