1. BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 24 The Immune System Modules 24.1 – 24.2

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Acquired immune deficiency syndrome (AIDS) is epidemic throughout much of the world 14,000 people are infected with the AIDS virus every day –HIV is the virus that causes AIDS –HIV is transmitted mainly in blood, semen, and vaginal secretions (drug use and unprotected sex) AIDS

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings HIV attacks the immune system –It eventually destroys the body’s ability to fight infection –Most people with HIV/AIDS die of other infections like pneumonia because their immune system can’t fight it

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The immune system protects the body against disease and infection. The skin is our first layer of defense, and prevents bacteria and viruses from entering the body Most bacteria/viruses enter the body through the nose, mouth, and eyes through breathing, eating, and touching infected particles The Immune System

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Antigens = BAD Antigens are molecules that trigger an immune response –They can be viruses, bacteria, mold, pollen, cancer, dust…

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Antibodies = GOOD Antibodies are proteins in our blood that recognize antigens, attach to them, and destroy them.

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vaccination Vaccines are harmless variants of disease causing microbes They are injected into the body, and our immune system recognizes them and produces antibodies If we encounter the disease again (like the flu or chicken pox) we already have antibodies ready to go

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vaccination Active immunity: the body is stimulated to produce antibodies in its own defense Passive immunity: when antibodies are given to a patient (such as through an injection or from mother to fetus)-this is temporary

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lymphocytes Lymphocytes are white blood cells –They are produced in the bone marrow –B cells (helper cells) produce antibodies –T cells (killer cells) attack infected body cells –Phagocytes are white blood cells that eat bacteria

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Endocrine System = Hormones Hormones are regulatory chemicals that travel through the blood. They are produced by glands (like the pituitary, hypothalamus, ovaries, testes) They are important in ALL body systems. They provide internal feedback and help maintain homeostasis.

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Miscellaneous: Feedback Loops Help maintain homeostasis If there is too much of something, the body makes less If there is not enough of something, the body makes more Are important in the endocrine and nervous systems.