Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Ch. 40 – The Body’s Defenses • What does your body need to defend itself from? Answer – Pathogens • Take a look at the different pathogens that exist.... • You come into contact with hundreds of pathogens each day. However, most people get sick only 1-3 times a year! • What are some first line defenses of your body that prevent you from getting sick? A. First Line of Nonspecific Defenses… 1. Skin (when unbroken) keeps out many pathogens. 2. Stomach Acid kills pathogens in food. 3. Mucous that lines respiratory passages, and trachea trap pathogens before they reach lungs. 4. Cilia are on the cells of respiratory tract continually sweep dust and pathogens up. B. Second Line of Nonspecific Defenses…. 1. Inflammatory Response (see handout) Injury like a cut or scrape causes this 2. Fever is helpful because pathogens don’t grow well in high temperatures. 3. Interferon Protein produced by cells infected with viruses. This protein causes nearby uninfected cells to produce enzymes to block the reproduction of the virus. C. Third Line of Specific Defenses…. -This is called an Immune Response. 1. Recognizing Pathogens Marker Proteins -All cells have _____________ which advertise their cell type. Human Muscle Cell Pathogen -WBCs recognize pathogens because they have “non-self” marker proteins…. foreign antigens 2. Destroying Pathogens -WBCs called Phagocytes & Lymphocytes… 1. Phagocytes - Ingest pathogens 2. Lymphocytes (Two Types): a. T-Cells -Destroy body cells infected w/pathogens b. B-Cells -Produce antibodies that destroy pathogens Pathogen -Antibodies attach to and destroy foreign antigens. -Antibodies are specific…there is a different antibody for every foreign antigen. *What do you think would happen if the same pathogen enters the body again? Answer: Memory WBCs remember the pathogen and stimulate the B cells to make the antibodies that were made the first time the pathogen was in the body. The antibodies destroy the pathogen immediately and you don’t get sick