Unit 10 Chapter 39 Immunity from Disease

1. Unit 10Chapter 39Immunity from Disease

2. The Nature of Disease • Pathogens • Disease producing agents, such as, bacteria, viruses, protozoans, fungi & other parasites • Infectious disease • Any disease caused by the presence of pathogens in the body

3. The Nature of Disease • Koch’s postulates of 1884 (a procedure to establish the cause of a disease) • 1) A pathogen must be found in the body of a sick organism • 2) The pathogen must be isolated & grown in the lab to produce a culture • 3) When the cultured pathogen is placed in a new host, it should cause the same disease • 4) The pathogen should be isolated from the new host and shown to be the original pathogen

4. The Nature of Disease • Endemic disease • Disease that are constantly present in a population (ex: common cold) • Epidemic • When many people in a given area are affected with the same disease at about the same time (ex: influenza)

5. The Nature of Disease • Antibiotics • Substances produced by microorganisms that, in small amounts, will kill or inhibit the growth & reproduction of other microorganisms • Ex: Penicillin, an antibiotic produced by a fungus, has been in use for over 50 years; many microorganisms are now resistant to penicillin

6. The Immune System • Innate Immunity • Your body’s own built-in defense system • First (& best) line of defense: • Unbroken skin • Body secretions, such as mucus, tears, sweat, & saliva

7. The Immune System • Second line of defense is inflammatory response: • Fever= increased body temperature slows or stops the growth of pathogens • Phagocytes = white blood cells, such as macrophages, that destroy pathogens • Interferon = proteins that protect cells from viruses

9. The Immune System • Third line of defense is cellular immunity: • Lymphocytes are types of white blood cells that defend the body against foreign substances • T cells are lymphocytes that defend against abnormal cells & pathogens inside livings cells • B cells are lymphocytes that provide immunity against antigens & pathogens in the body fluids

11. The Immune System • Lymph • Tissue fluid (to bathe, nourish cells) after it enters the lymph vessels that will return it to the blood • Lymph nodes • Glands that filter pathogens from the lymph before it returns to the bloodstream

14. The Immune System • Acquired Immunity • Defending against a specific pathogen by gradually building up a resistance to it. • Passive = acquired naturally when antibodies are transferred from mother to unborn child through the placenta • Active = acquired artificially when induced by vaccines

15. Nonspecific defense Click on image to play video.

16. Cellular immunity Click on image to play video.