1. Infectious Diseases

2. Causes of Infectious Diseases Pathogens 1.Bacteria: single celled microorganism, after entering the body they multiply quickly by division Video Video 2.Viruses: piece of genetic material surrounded by a protein coat, invade cells of living organisms video video 3.Rickettsias: resemble bacteria, enter body through insect bites

3. Causes of Infectious Diseases Cont. 4.Protozoa: single celled organisms that are larger than bacteria and have a more complex cell structure 5.Fungi: plantlike organisms that can cause disease of the lungs, mucus membranes and skin

4. How are Infectious Diseases Spread? 1.Direct Open wounds Childbirth Contact with infected animals 2.Indirect Contaminated objects Vectors Contaminated food and water 3.Airborne

5. Common Infectious Diseases 1.Respiratory infections Common Cold / virus causes inflammation of mucas membrane, direct or indirect contact Influenza / virus infection of respiratory tract Flu vaccination???? Pro and con?? Pneumonia / virus or bacteria, flu spreads to lungs Tuberculosis / bacterial infection in lungs Strep throat / bacterial infection 2.Hepatitis A / contracted through fecal matter B / contracted through blood or sexual contact C / contracted through blood or sexual contact Lead to liver damage or cancer

6. The Immune Response 1.Physical Barriers Skin, Mucus membranes, Cilia 2.Chemical Barriers Enzymes in tears and saliva Acid in stomach

7. Inflammatory response Non-Specific 1.Blood vessels near injury expand. 2.Fluid and cells from blood surround area. 3.Phagocytes surround pathogens and kill them with special chemicals. Puss may build up. 4.Body begins to repair.

8. Specific Resistance Lymphocytes 1.B Cells Turn into plasma cells that produce antibodies 2.T Cells Helper T cells, begin production of B cells and Killer T cells Killer T cells, destroy infected cells Suppressor T cells, suppress Killer T cells when infection is gone VideoVideo Figure 23.6 on page 641

9. Preventing Infectious Diseases 1.Immunity Active - develop immunity naturally or artificially (exposure or vaccine) Passive - antibodies through another person or animal (mother or animal) 2.Vaccines Live virus Killed virus Toxoids Hi