Lymphatic System & Immunity Mrs. Donohue

1. What is the lymphatic system? A. Consists of lymphatic vessels and nodes B. runs beside our circulatory system C. lymphoid organs

Lymphoid organs 1. Tonsils - protect against invasion of particles that are ingested or inhaled 2. spleen- blood reservoir phagocytes filter foreign materials and old red cells there 3. thymus – changed lymphocytes into T cells (help fight viruses)

2. How does it help our body? A. Helps to maintain fluid balance in tissues B. absorb digested fats and vitamins from GI C. part of body’s defense against disease (lymphocytes)- WBC’s

3. What is immunity? A. Preventing disease thru production of antibodies and other plans of attack B. Also to recognize its own tissues and not attack itself – immunological tolerance

4. What is a pathogen? Disease causing agent Anything that enters the body that is not related to the body Examples: A. such as the bacterium Yersinia pestis, which may have caused the Black PlagueYersinia pestis Black Plague B. Viruses C. Splinter

5. Types of immunity: A. non-specific (innate) defense mechanisms 1. inherited as part of each organism to attack pathogens 2. epithelial membranes 3. acidity of gastric juices

5. Types of immunity: B. specific (aquired) immune response 1. can aquire ability to defend against pathogens by prior exposure to those pathogens 2. make antibodies

6. Non-specific Defense (resistance): 1st line of defense 1. skin 2. mucus and cilia that line nasal cavities and throat 3. gastric (stomach) juice- acidic pH 4. saliva 5. tears

B1. 2nd line of defense (resistance) inflammation response 1. Phagocytic cells-leukocytes-white cells neutrophils, monocytes & macrophages A.attack pathogens B.release histamine that stimulates blood flow-vasodilates-result is swelling and reddening of infection area

Inflammation Response

B2. 2nd line of defense (resistance) inflammation response A. Cells being attacked (T cells) produce interferon B. a protein that prevents viruses (and some cancers) from replicating C. slows down viral infections and allows immune system to function

B3. 2nd line of defense (resistance) inflammation response A. Complement System B. Makes plasma proteins

B4. 2nd line of defense (resistance) inflammation response A. Fever B. bacteria secrete endotoxin C. Monocytes (white cells) secrete endogenous pyrogen D. go to brain-get fever-also interferes with bacteria taking in iron

4A. Purpose of Fevers 1. increases action of white blood cells 2. produces a temperature range in which many pathogens can not live

7. Specific Defense:3rd line of defense-The Immune System Purpose: to produce antibodies and specialized cells that bind and inactivate pathogens

A. Antigen - Pathogen (antibody generator) –tells body to make antibodies usually a protein on the surface of a pathogen-ID marker

B. Sequence of Events for each pathogen 1. recognize pathogen 2. attack 3. destroy 4. remember – memory cells om/index.cfm?fuseac tion=vids.individual& videoid= http://vids.myspace.c om/index.cfm?fuseac tion=vids.individual& videoid=

Types of Immunity: 1. Active Immunity Artificial Acquired A. Vaccines-mumps, chicken pox, polio B. Result of prior exposure to an antigen C. Make antibodies D If body comes into contact with the antigen – the antibodies kill it Not get sick

A. Active Immunity - Primary Response Body produces its own antibodies after vaccine (exposed for 1 st time) 1. Takes 5-10 days to make antibodies 2. May get sick before antibodies are made

B. Active Immunity - Secondary Response Result is much more rapid and intense 1.Had prior exposure 2. Have antibodies (memory cells) B & T cells 3. make more clones 4. Either never get sick at all or feel sick for one day

2. Passive Immunity 1. Person receives antibodies from another organism (human) Mom gives natural passive immunity to the fetus for 3 months Breast – feeding – baby gets IgA 2. Snake bite – give antiserum = antibodies (made from horse or sheep that made antibodies when injected with the venom) Neutralizes the venom Person does not develop active immunity

3.Cellular Immunity (cell-mediated) A. killer T cells release perforin B. directly destroys pathogen C. Antibodies are not made

4. Humoral (antibody-mediated) immunity Lymphocytes (T & B cells) B cells (plasma cells)—make antibodies

Normal Immune System T cells directly kill pathogens Helper T cells help the killer T cells kill the pathogen Suppressor T cells turn off the helper and killer T cells after the pathogen is dead

HIV Vs AID’s HIV - tested positive for the virus AIDS - syndrome caused by HIV - immune system problems appear Usually takes ten years

HIV-Human Immunodeficiency Virus Virus enters T lymphocytes (killer, helper, & suppressor) Changes the DNA of the lymphs New lymphs kill helper and killer lymphocytes

HIV-Human Immunodeficiency Virus Pathogen enters the body Not enough killer or helper T cells to kill pathogen Patient becomes septic-septicemia Most deaths from HIV are from infection

How to treat HIV Decrease viral load=# of HIV cells in body Allows normal # of T cells-can fight infection “Cocktails” “Nukes”-block HIV ability to copy cell’s DNA-can’t make new viral copies Protease inhibitors – prevent infected cells from releasing HIV into body Fusion inhibitor – prevents entry of HIV into the body’s healthy cells

Why no cure for HIV? Can’t develop vaccine DNA keeps changing