Immunity 1

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Immunity 1

  1. 1. Immunity
  2. 2. The Immune System <ul><li>Animals defend themselves against pathogens by both nonspecific and specific means. </li></ul><ul><li>Many of our defenses are implemented by cells and proteins carried in the bloodstream and in the lymphatic system. </li></ul><ul><li>White blood cells, including lymphocytes (B and T cells) and phagocytes (such as neutrophils and macrophages), play many defensive roles. </li></ul>
  3. 3. Immune System <ul><li>The immune system is made up of cells that work with the body’s physical and chemical barriers. </li></ul><ul><li>It helps prevent any pathogen (disease-causing organism) entering the body. </li></ul><ul><ul><li>Note: Harmful bacteria is an example of a pathogen. </li></ul></ul><ul><li>If the worst comes to the worst and any pathogens do get into our body, the immune system tries to stop them from causing harm. </li></ul><ul><li>A person begins to experience the symptoms of the disease if the pathogens manage to multiply, produce toxins and damage the cells. </li></ul>
  4. 4. Nonspecific Defenses An animal's nonspecific defenses include physical barriers, competing resident microorganisms, and local agents, such as secretions that contain an antibacterial enzyme.
  5. 5. Physical and chemical barriers <ul><li>The first line of defense is made up of physical and chemical barriers. </li></ul><ul><li>These types of barriers are non-specific (That is if any organism is not recognized, it is assumed to be a pathogen, and will be treated the same way). </li></ul><ul><li>These barriers occur at the skin or any other openings to the outside world. </li></ul>
  6. 6. Physical Barriers <ul><li>Skin: </li></ul><ul><li>It is a hard outer layer that generally prevents the entry of any undesirables. </li></ul><ul><li>Nose, throat and digestive tract: </li></ul><ul><li>The membrane lining these, secretes sticky mucus to trap microbes. Fine hairs called cilia waft the mucus away. </li></ul>
  7. 7. Chemical Barriers <ul><li>Eyes: </li></ul><ul><li>Tears have lysozyme enzyme in them. This kills some bacteria. </li></ul><ul><li>Ear: </li></ul><ul><li>Ear wax has antimicrobial properties. </li></ul><ul><li>Stomach: </li></ul><ul><li>Hydrochloric acid in the stomach kills bacteria. </li></ul><ul><li>Large intestine, urethra and vagina: </li></ul><ul><li>Resident harmless bacteria use the nutrients that any harmful microbes would need to survive (harmless bacteria out-compete the harmful bacteria). </li></ul><ul><li>Sweat: </li></ul><ul><li>Sweat is an acidic liquid that contains enzymes which kills some bacteria. </li></ul>
  8. 8. Inflammatory response

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