Lymphatic System and Immunity

1. Lymphatic System andImmunity By Melanie E. Alexis C. Lavinia G.

2. General Functions • Lymphatic System circulates the lymph fluid throughout the body • Immunity= Lymph fluid consisting of antibodies and lymphocytes • Fluid and Protein Balance= prevents loss of fluids by collecting it in the lymphatic vessels and returning it to the circulatory system • Digestion= help in the absorption of fats from food, prevents obesity • Excretion= assists in excretion of waste materials from the body • Transportation of nutrients= delivers nutrients in the body through the blood

3. Major Organs

4. Skin= forms germ-proof barrier • Nose= hairs and mucus trap germs and dirt from air • Ears= wax inside traps germs • Eyelids= keeps germs out of your eyes • Tears= wash eyes clean • Stomach= hydrochbris acid kills germs in food • Tonsils and Adenoids= kills germs in throat • White Blood Cells= destroying germs inside your body • Spleen= contains white blood cells which fight infection

5. Lymph Capillaries Lacteals Lymph Nodes Lymph Vessels Main Lymphatic Ducts

6. Lymph Node • Lymph nodes are small organs found in clusters around the system in your neck, armpits and groin. • Make lymphocytes which destroy germs with chemicals called antibodies. • Special antibodies attacks specific antigens • Are located along lymphatic pathways • Filters any possible harmful partials from the lymph before it travels to the blood stream • Center for lymphocyte production

7. The Spleen • Produces lymphocytes (type of white blood cells) • Red pulp is concerned with filtration activities, removing damaged red blood cells from the body • Reservoir of blood • Preserves iron and important components from damaged blood cells • Stored as bilirubin and ferritin • Stores monocytes (helps engulf and digest bacteria and other harmful microorganisms

8. The Thymus • Most active in youth • Enlarges as you grow older (then recedes at its peak) • Produces hormones that regulate T-cell growth

9. Immunoglobins (Antibodies) • Antibodies attack antigens, help activate proteins to attack or make changes in local areas to protect it from antigens spreading • Immunoglobulin A: found in exocrine gland secretions. Breast milk, tears, nasal fluid, gastric juice, intestinal juice, bile and urine • Immunoglobulin G: plasma tissue fluids, is particularly effective against bacteria, viruses, and toxins. Actives group of immune system enzymes called complement • Immunoglobulin M: type of antibody that develops in the blood plasma in response to contact with certain antigens in food or bacteria. Also activates complement. • Immunoglobulin D: found on the surfaces of most B cells, especially those of infants. Also is important in activating B cells. • Immunoglobulin E: appears in exocrine secretions along with Lg A. It is associated with allergic reactions.

10. Primary/Secondary Immune Responses • Primary Immune Response= when B or T cells become activated for the first time after which some cells remain as memory cells • Secondary Immune Response= when the same antigen is encountered again

11. Active/Passive Immunity • Natural active immunity occurs when is a person is exposed to a live pathogen, develops the disease and becomes immune • Artificially acquired active immunity can be gained by a vaccine (a substance that contains the antigen) • a vaccine stimulates a primary response against the antigen without causing symptoms of the disease • Natural passive immunity occurs during pregnancy, when certain antibodies are passed from the mother to the child through the bloodstream • Artificially acquired passive immunity is gained through injection of antibodies

12. Allergic Reactions • Allergic reactions to allergens are excessive immune responses that can lead to tissue damage • Mast cells release histamine and leukotrienes, producing a variety of effects • Delayed-reaction allergy= results from repeated exposure to substances that cause inflammatory reactions in the skin • Immediate-reaction allergy= inherited ability to overproduced IgE

13. Tissue Rejection Reactions • A transplant recipient’s immune system may react with foreign antigens on the surface of the transplanted tissue, causing a tissue rejection reaction • Closely matched tissues reduce the chance of tissue rejection, and use of immunosuppressive drugs may reduce rejection, although the individual may be more susceptible to infection

14. Autoimmunity • In autoimmunity disorders, the immune system manufactures antibodies against some of its own antigens • Autoimmune disorders may result from viral infection, faulty T cell development, or reaction to a nonself antigen that bears close resemblance to a self antigen

15. Diseases: HIVs • - “Human Immunodeficiency Virus” • Breaks down immune system by infecting immune cells • HIV infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and dendriticcells • When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections.

16. Diseases: SCID • (Severe Combined Immune Deficiency) • A genetic disorder identified by the absence of working T-lymphocytes • Creates a defective antibody response • It is the most severe form of primary immunodeficiencies • Its known as the bubble boy disease because the patients are extremely vulnerable to infectious diseases • Patients are usually affected by severe bacterial, viral, or fungal infections early on and often present with, chronic diarrhea, interstitial lung disease, and failure to thrive

17. Scleroderm • Is a chronic systemic autoimmune disease • derma = skin • Limited systemic sclerosis/scleroderma • Diffuse systemic sclerosis/scleroderma • The cause is unknown •  affects the small blood vessels in all organs