1. How to Use This Presentation To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show”, or simply press F5 on the top row of your keyboard. To advance to the next slide click the left mouse button once. From the Chapter screen you can click on any section to go directly to that section’s presentation. Blank or “missing” areas of a slide will remain hidden until the left mouse button is clicked. You may exit the slide show at any time by pressing the Esc key Copyright © by Holt, Rinehart and Winston. All rights reserved.

2. Body Defenses and Disease Chapter 27 Section 1: Disease Section 2: Your Body’s Defenses Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

3. Disease Section 1 Bellringer Brainstorm as many different names of diseases as you can. Don’t forget to list both physical illnesses and mental illnesses. How do you think people get these diseases? Are all of the diseases contagious? Have you ever had any of the diseases you listed? If so, did you understand how you became ill and what could help you recover? Record your answers in your science journal. Copyright © by Holt, Rinehart and Winston. All rights reserved.

4. Disease Section 1 Objectives Explain the difference between infectious diseases and noninfectious disease. Identify five ways that you might come into contact with a pathogen. Discuss four methods that have helped reduce the spread of disease. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

5. Disease Section 1 Causes of Disease Noninfectious Disease Some diseases, such as most cancers and heart disease, are not spread from one person to another. They are called noninfectious diseases. Infectious Disease A disease that can be passed from one living thing to another is an infectious disease. Infectious diseases are caused by agents called pathogens. Viruses and some bacteria, fungi, protists, and worms may all cause diseases. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

6. Disease Section 1 Pathways to Pathogens Air Some pathogens travel through the air. Contaminated Objects Contaminated doorknobs, keyboards, combs, and towels can pass pathogens. Person to Person You can become infected with some illnesses by kissing, shaking hands, or touching the sores of an infected person. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

7. Disease Section 1 Pathways to Pathogens pathogens Animals Some pathogens are carried by animals. For example, humans can get a fungus called ringworm from handling an infected dog or cat. Food and Water Bacteria growing in foods and beverages can cause illness. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

8. Disease Section 1 Putting Pathogens in Their Place Pasteurization The method of using heat to kill most of the bacteria in the wine is called pasteurization. Vaccines and Immunity The ability to resist or recover from an infectious disease is called immunity. A vaccine is a substance that helps your body develop immunity to a disease. Antibiotics An antibiotic is a substance that can kill bacteria or slow the growth of bacteria. Antibiotics may also be used to treat infections caused by other microorganisms, such as fungi. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

9. Your Body’s Defenses Section 2 Bellringer Make a list in your science journal of all the different ways pathogens might enter the body. Is there anything that you do to avoid getting sick? Do you know of anything that your body automatically does to get rid of pathogens? Copyright © by Holt, Rinehart and Winston. All rights reserved.

10. Your Body’s Defenses Section 2 Objectives Describe how your body keeps out pathogens. Explain how the immune system fights infections. Describe four challenges to the immune system. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

11. Your Body’s Defenses Section 2 First Lines of Defense Your Skin Your skin is made of many layers of flat cells. The outermost layers are dead. As a result, many pathogens that land on your skin have difficulty finding a live cell to infect. Copyright © by Holt, Rinehart and Winston. All rights reserved. Pathogens Invade Sometimes, skin is cut or punctured and pathogens can enter the body. The body acts quickly to keep out as many pathogens as possible. Blood flow to the injured area increases. Cell parts in the blood called platelets help seal the open wound so that no more pathogens can enter. Failure of First Lines End of Slide

12. Your Body’s Defenses Section 2 Cells of the Immune System Macrophages and More Macrophages engulf and digest many microorganisms or viruses that enter your body. T cells coordinate the immune system and attack many infected cells. B cells are immune-system cells that make antibodies. Antibodies, shown on the next slide, are proteins that attach to specific antigens. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

13. Your Body’s Defenses Section 2 Copyright © by Holt, Rinehart and Winston. All rights reserved. Immune Response If virus particles enter your body, some of the particles may pass into body cells and begin to replicate. Other virus particles will be engulfed and broken up by macrophages. Responding to a Virus End of Slide

14. An Antibody’s Shape Fits an Antigen Section 2 Copyright © by Holt, Rinehart and Winston. All rights reserved.

15. Immune Response: A Section 2 Copyright © by Holt, Rinehart and Winston. All rights reserved.

16. Immune Response: B Section 2 Copyright © by Holt, Rinehart and Winston. All rights reserved.

17. Your Body’s Defenses Section 2 Fevers Turning Up the Heat A moderate fever of one or two degrees actually helps you get well faster because it slows the growth of some pathogens. Copyright © by Holt, Rinehart and Winston. All rights reserved. Specific Antibodies Memory B cells are cells in your immune system that “remember” how to make an antibody for a particular pathogen. If the pathogen shows up again, the memory B cells produce B cells that make enough antibodies in just 3 or 4 days to protect you. Memory Cells End of Slide

18. Your Body’s Defenses Section 2 Challenges to the Immune System Allergies With allergies, the immune system overreacts to antigens that are not dangerous to the body. Autoimmune Disease A disease in which the immune system attacks the body’s own cells is called an autoimmune disease. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

19. Your Body’s Defenses Section 2 Challenges to the Immune System continued Cancer Cancer is the condition in which cells divide at an uncontrolled rate. AIDS The acquired immune deficiency syndrome (AIDS) is caused by HIV, which infects the immune system itself, using helper T cells as factories to produce more viruses. Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide

20. Body Defenses and Disease Chapter 27 Concept Map Copyright © by Holt, Rinehart and Winston. All rights reserved. Use the following terms to complete the concept map on the next slide: hemophilia, pathogens, immune system, fungi, viruses, protists, infectious diseases, noninfectious diseases.

21. Concept Map Chapter 27 Copyright © by Holt, Rinehart and Winston. All rights reserved.

22. Concept Map Chapter 27 Copyright © by Holt, Rinehart and Winston. All rights reserved.