1. Unit Question: What is life and how does it maintain balance? Notes #8: The Immune System and Homeostasis Aim: What does your immune system do? Name:________________

2. Pathogens When an organism is unable to maintain homeostasis, the organism has a disease Pathogens are viruses and bacteria that cause disease The body’s immune system repels pathogens and reestablishes homeostasis

3. An Immune Attack What the immune system does when a pathogen enters the body: 1.Pathogens release antigens (foreign substances) 2.Antibodies are released by the immune system to fight the pathogen. 3. Antibodies have receptors on their cell membranes that recognize and bind to the antigens.

4. Vaccines Weakened pathogens that are injected into the body The body produces antibodies which remain in the system in case of another infection by the same pathogen

5. Salmonella bacteria can cause humans to have stomach cramps, vomiting, diarrhea, and fever. The effect these bacteria have on humans indicates that Salmonella bacteria are (1) Predators (2) pathogenic organisms (3) parasitic fungi (4) decomposers The virus that causes AIDS is damaging to the body because it (1) targets cells that fight invading microbes (2) attacks specific red blood cells (3) causes an abnormally high insulin level (4) prevents the normal transmission of nerve impulses

6. Many viruses infect only a certain type of cell because they bind to certain (1) other viruses on the surface of the cell (2) mitochondria in the cell (3) hormones in the cell (4) receptor sites on the surface of the cell Vaccinations help prepare the body to fight invasions of a specific pathogen by (1) inhibiting antigen production (2) stimulating antibody production (3) inhibiting white blood cell production (4) stimulating red blood cell production

7. A vaccine used against an infectious disease may contain (1) specialized blood cells (2) toxic enzymes (3) a variety of antibiotics (4) weakened pathogens

9. The use of a vaccine to stimulate the immune system to act against a specific pathogen is valuable in maintaining homeostasis because (1) once the body produces chemicals to combat one type of virus, it can more easily make antibiotics (2) the body can digest the weakened microbes and use them as food (3) the body will be able to fight invasions by the same type of microbe in the future (4) the more the immune system is challenged, the better it performs

10. The virus that causes AIDS is damaging to the body because it (1) targets cells that fight invading microbes (2) attacks specific red blood cells (3) causes an abnormally high insulin level (4) prevents the normal transmission of nerve impulses State one specific way white blood cells help to protect the human body from pathogens. ______________________________________________ ______________________________________________