The Lymphatic System Function 1: to return interstitial fluid to blood stream Function 2: to provide working location for immune systemx

IMMUNE SYSTEM Immunity is the ability to defend against pathogens. Pathogen: an organism or virus that causes disease. ex. infectious agents, foreign cells, even abnormal body cells (cancer).

NONSPECIFIC DEFENSE SKIN CILIA MUCOUS MEMBRANES STOMACH ACID RESIDENTIAL BACTERIA Sweat, tears, saliva have lysozyme. keratin

INTERFERONS Small proteins Active only against viruses Released by invaded cell To “warn” neighbor cells Inhibit reproduction of viruses.

Inflammatory response Skin is cut Histamines released by damaged cells WBC’s attracted (phagocytes) Blood flow increased Capillaries permeable to phagocytes Phagocytes ingest pathogens by endocytosis Local temp rises Blood clot forms with platelets Hot, red, swollen, painful. :(

BLOOD CELLS 1 in 1000 blood cells is a leukocyte A. ERYTHROCYTES B. LEUKOCYTES Phagocytes Lymphocytes.

Phagocyte: NEUTROPHILS 50-70% OF WBC’S Push thru capillaries to phagocytize invaders Filled with lysosomes with hydrolytic enzymes.

Phagocyte: BASOPHILS Role in allergic reaction release histamines. 0.1% OF WBC’s Role in allergic reaction release histamines.

Phagocyte: EOSINOPHILS 1-4% of WBC’s Infections with parasites Granules have toxins.

Phagocyte: Monocytes Circulate & Lodge in spleen, liver, lungs, lymph nodes Transformed into MACROPHAGES in tissues Ingest bacteria and viruses “cell eaters” 2-8% of WBC’s Activate Helper-T cells (lymphocytes) by presenting antigen

Lymphocytes: Specific defense 20 - 40% of WBC’s 2 types: B (bone) cells for humoral immunity T (thymus) cells For cell-mediated immunity Secrete lymphokines (interleukins to activate B cells and attract macrophages)

B lymphocytes have antigen receptors produce antibodies (proteins) offer humoral immunity activated by helper-T cells

Antibody activity 1. Coat & Clump “agglutination” 2. Combine & Interfere “neutralization” 3. With complement, lyse & destroy. antibody

Clonal selection theory of B lymphocytes

IMMUNE RESPONSE PRIMARY: plasma & memory cells day zero exposure SECONDARY: immediate day 28 exposure Vaccinations (heat killed, weakened, close strains) Passive immunity versus Active immunity.

T Lymphocytes mature in the thymus; several types helper T cells (recognize Class II MHC) Activate B plasma cells with receptor cytotoxic T cells (recognize Class I MHC) Attack and lyse invaded cell (or cancer cell) Or make clones & memory cells Or release chemicals to attract monocytes Or release toxins or interferons natural killer cells attack tumors & microbes do not need specific antigen supressor T cells turn off immune response.

Major Histocompatability Complex MHC Class I for body cells (nucleated) Class II for immune cells 20 different glycoproteins each with 8-10 choices.

Helper T Cells

Cytotoxic T Cells

Central Role of Helper T Cells

Immune system Nonspecific: Specific: anatomic barriers,inflammatory, interferons Specific: Humoral with B-cells and antibodies Cell mediated with T-cells.

HIV - AIDS Human Immunodeficiency Virus is responsible for Acquired Immune Deficiency Syndrome HIV infects the helper T-cells. Body is vulnerable to opportunistic pathogens. Transmission: bodily fluids i.e. blood, sex, breast milk, across placenta

HIV

Helper T Cell releasing HIV

Citations http://www.merckmanuals.com/home/immune_disorders/biology_of_the_immune_system/overview_of_the_immune_system.html http://www.daviddarling.info/encyclopedia/L/lymphatic_vessel.html http://www.acm.uiuc.edu/sigbio/project/updated-lymphatic/lymph7.html http://www.mobileapptesting.com/mobile-devices-infected-with-real-viruses/2010/10/virus/ http://www.goodpsych.com/stress-psychology/inflammation-gone-wild.html http://lima.osu.edu/biology/archive/cardiovascular_system.htm http://www.udel.edu/biology/Wags/histopage/wagnerart/modelspage/models.html http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit5/humoral/abyproduction/u3fg2g.html http://www.biology.arizona.edu/immunology/tutorials/antibody/structure.html http://www.aegis.com/topics/basics/hivandaids.html

Cytotoxic T-cell attacking a body cell infected with a virus.