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

Thymus Function

lymphatic tissue primary role:

changes lymphocytes to T cells for cellular immunity

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 

- trap and destroy bacteria

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

blockage of lymph drainage

Edema

lowers colloid osmotic pressure Increase hydrostatic pressure poor lymph drainage increased capillary permeability as in

inflammation

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)

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

Allergy

Allergy is one of four forms of hypersensitivityAllergic 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

Anaphylaxis

Specific allergen enters vascular system

Reaction occurs of allergen –IgE that attached to basophil

Histamine released into the circulation

Treated with epinephrine

Urticaria

Resulting from antigen entering skin area

Histamine released and causes vasodilatin and increase permeability of the capillaries

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

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

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