The Immune System. Protective system that fight disease in the body. Includes parts of the circulatory system and lymph system.

Transcription

1 The Immune System Protective system that fight disease in the body. Includes parts of the circulatory system and lymph system. The immune system recognizes, attacks, destroys, and remembers each kind of pathogen or foreign substance that enters the body.

2 Definitions Immunity the ability to fight off an infection. Immune Response how the body reacts to a foreign object Antigen any substance that can cause an immune response

3 Virus Animation

4 Pathogens A pathogen is something that causes disease.

5 First Line Defense Physical and chemical barriers that prevent pathogens from getting into the body. Include: skin, mucus membranes, tears.

6 Mucus Membranes Mucous membranes line the digestive system, nasal passages, lungs, respiratory passages, and the reproductive tract. Like the skin, mucous membranes serve as a barrier to pathogens and are involved in the body's defenses.

7 Second Line Defense The defense against pathogens that have breached the external defense mechanisms. Include Inflammatory response

8 Inflammatory Response The inflammatory response is a protective response of tissues affected by disease or injury and is characterized by heat, redness, swelling, and pain.

9 The inflammatory response actually stimulates other protective cells to come to the rescue at the wound site. The cells at the wound produce chemicals that cause gaps to form in the blood vessel lining Phagocytes (White blood cells) will come and engulf the pathogens

10 Interferon Sometimes cells at the wound site sense that a virus is present. The cells produce a chemical called interferon which inhibits the viruses from reproducing.

11 Fever as a Nonspecific Defense Fever is an elevation of the body temperature above the normal 37 C (98.6 F) temperature. Fever usually occurs as a natural defense against infection by viruses or bacteria that invade the body. A high fever may actually kill unwanted bacteria.

12 White Blood Cells Neutrophils engulf (eat) bacteria Macrophages also engulf bacteria and cell debris Natural Killer Cells kills the body s cells that are infected by a pathogen.

13 Cell Mediated Immune Response When a pathogen enters the body the immune system responds. 1 st a macrophage engulfs and digests the pathogen.

14 The macrophage cuts up the antigen into pieces and presents pieces of the pathogen on its surface.

15 Helper T cells will bind to the pieces of the antigen. This activates the Helper T cells.

16 The macrophage will now produce a chemical called Interleukin 1

17 This stimulates the Helper T cells to produce Interleukin 2 Interleukin 2 stimulates the helper T cells to now produce three new types of cells: More Helper T cells Cytotoxic T cells Suppressor T Cells

18 Cytotoxic T Cells Cytotoxic T cells recognize the infected cells by their antigens.

19 They destroy the infected cells by puncturing the cell membranes.

20 The infected cell is destroyed. The Cytotoxic T cell leaves to fight again.

21 Macrophages Will engulf the destroyed cells presenting their cells fragments to produce more helper T Cells

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23 Suppressor T Cells Suppressor T cells shut down immune response when the pathogen is cleared from the body

24 Memory Cells Some T cells remain in the blood stream as memory cells available to re-start the immune response at a moments notice if the same antigen is presented again.

25 Antibody Mediated Immune Response Bacterial Pathogens enter the cell. B-Cells bind with the Bacteria

26 The bacteria is pulled into the cell and digested.

27 The B Cell presents fragments of the bacteria on its surface.

28 Helper Cell Helper cells bind with the antigen presenting B cell

29 Helper Cell The Helper cell releases interleukins to stimulate the B cell to divide.

30 The B cell divides into memory cells and effector B cells. Memory cells are used in the future

31 Effector B cells start producing millions of antibodies. Antibodies are like cellular labels. They bind to the specific pathogen and indicate to the macrophages Here it is

32 The cells and or pathogens labeled with antibodies are engulfed by macrophages, destroying the infection. A Macrophage will recognize the labels on the outside of the cell. The macrophage will engulf and digest the harmful cell and or pathogen

33 Primary Immune Response A primary immune response is an immune response that occurs when an antigen is encountered for the first time. For Example: Production of antibodies Production of T and B cells

34 Secondary Immune Response A secondary immune response is the response to a subsequent infection by the same pathogen. The use of preexisting antibodies, T and B cells. Much faster response time.

35 Secondary immune response allows the body to respond much faster to re-infection by pathogens encountered previously. In many cases, if the same pathogen invaded your body, your immune system will eliminate it before you even felt sick.

36 Vaccine A vaccine is a solution that contains a harmless version of a virus, bacterium, or toxin and that causes an immune response when introduced into the body. The body creates memory cells and antibodies to the harmless virus or bacteria. When the real thing enters the body the immune system is prepared to fight it off.

37 Antigen Shifting As the virus changes over time, it becomes different enough to evade the memory immune response. This is known as antigen shifting. In this process, a virus produces new antigens as it mutates over time.

38 Multiple Sclerosis Multiple sclerosis is a chronic disabling disease of the central nervous system.

39 AIDS (Acquired Immunodeficiency Syndrome) AIDS, or acquired immunodeficiency syndrome, is a fatal disease caused by infection by the human immunodeficiency virus (HIV), resulting in a depressed immune system.

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41 Allergies A massive immune response to a harmless antigen.

42 Sexually Transmitted Diseases Sexually transmitted infections (STIs) are infections you can get by having sex with someone who has an infection. These infections are usually passed by having vaginal intercourse, but they can also be passed through anal sex, oral sex or skin-to-skin contact. STIs can be caused by viruses or bacteria. STIs caused by viruses include hepatitis B, herpes, HIV and the human papilloma virus (HPV). STIs caused by bacteria include chlamydia, gonorrhea and syphilis. 1 in 10 teenagers has an STD 1 in 4 teen girls has an STD