The thymus is a two-lobed organ located in the upper chest that matures T cells from the bone marrow. T cells help fight infections. Tonsils trap and destroy bacteria in the throat and help the immune system. Lymphedema is swelling caused by damage to the lymphatic system from tumors, parasites, or surgery. Hypersensitivity refers to unwanted immune reactions and is classified into four types: Type I is immediate allergy responses, Type II involves antibodies attacking self cells, Type III occurs when immune complexes form, and Type IV is delayed hypersensitivity mediated by T cells. Allergies occur when IgE antibodies attach to mast cells and trigger histamine release in response to allergens.

1. Thymus two-lobed organ located in upper part of chest along trachea immature T cells originating in the bone marrow migrate to thymus via blood in thymus, cells develop into mature T cells for release into circulation

3. primary role: changes lymphocytes to T cells for cellular immunityThymus Function

4. Tonsils Two masses of tissue on either side of the back of the throat Assist the body in its defense against incoming bacteria and viruses Three types: pharyngeal tonsils Palatine tonsil lingual tonsils

5. - trap and destroy bacteria

7. blockage of lymph drainage Lymphedema Is a condition of localized fluid retention and tissue swelling due to damage of lymphatic system - due to tumor pressure, parasites, or surgery

8. Edema lowers colloid osmotic pressure Increase hydrostatic pressure poor lymph drainage increased capillary permeability as in inflammation

9. Hypersensitivity Refers to undesirable reactions produced by the normal immune system There are four groups classification: Type I (allergy) Type II (Antibody dependent) Type III (Immune complex diseases Type IV (Delayed type hypersensitivity)

10. Classification of Hypersensitivity Diseases Type Immunologic Mechanisms Examples Type I: Immediate hypersensitivity Type II: Antibody Mediated Type III: Immune complex Mediated Type IV: Delayed type hypersensitivity T-cell mediated IgE antibody mediated-mast cell activation and degranulation Antibodies (IgM, IgG) formed Against cell surface or matrix Ags. Complement is usually involved Immune complexes of circulating antigens.Complement and Leukocytes (neutrophils, macrophages) are often involved. Mononuclear cells (T lymphocytes, macrophages) involved. Th1 diseases Allergies (“Hay fever”), asthma,anaphylaxis Autoimmune hemolytic anemias,Myasthenia gravis, Rheumatic fever, Graves disease Serum sickness, Lupus, glomerulonephritis Diabetes, Rheumatoid Arthritis, Inflammatory Bowel Disease; Multiple sclerosis

11. Allergy Allergy is one of four forms of hypersensitivity Allergic person who has excess IgE The allergic tendency is genetically passed from parent to child Characterized by presence of large quantities if IgE (reagins) in the blood IgE attached to mast cells and basophils Antigen (allergen) react with IgE that attached to mast cell and basophil Some of mast cell produce chemical substance Attract neutrophils to the reactive site

12. Anaphylaxis Specific allergen enters vascular system Reaction occurs of allergen –IgE that attached to basophil Histamine released into the circulation Treated with epinephrine

13. Urticaria Resulting from antigen entering skin area Histamine released and causes vasodilatin and increase permeability of the capillaries

14. Hay fever The allergen- reagin reaction occurs in the nose Histamine released in response to the reaction leads to increase capillary pressure and permeability Using antihistamine prevent swelling reaction

15. Asthma The allergen- reagin reaction occurs in the bronchioles of the lungs Product released from mast cell called slow reacting substance of anaphylaxis which caused spasm of smooth muscles

16. Type II (Antibody Mediated) Antibodies produced by the immune response bind to antigen on the patients own cell surface Autoimmune hemolytic anemia: where the body immune system attacks its own RBCs leading to their destruction Drugs bind to RBC causing them to be recognized different. IgM and IgG antibodies bind to these antigens that cause cell lysis and death