Anatomy and Physiology Review Immunity Process

Antigen

Substances that the body considers not part of self that induce an immune response

Immunity

This could be defense against pathogens, removal of worn-out cells & tissue debris, identification & destruction of abnormal cells, and rejection of foreign cells

Immune System

Collection of cells, tissues and molecules that mediate resistance to infections, consists of leukocytes/WBCs

Normal range for WBC

4,500 - 10,000

Leukocytosis

Elevated WBC count

Leukopenia

Decreased WBC count

Organs that contain/produce leukocytes

adenoids, tonsils, lymph nodes, thymus, spleen, lymphatic vessels, peyer’s patches, appendix, bone marrow

Innate Immunity

Present at birth, responds rapidly, gives the same response to all antigens, no immunologic memory

1st Line Defenses

Prevent entry of pathogens

2nd Line Defenses

Contain or kill pathogens that have entered the body

1st line defense consists of

Skin, respiratory tract, gastrointestinal tract, tears, nasal, secretions & saliva, sperm ,vagina

Skin does what in the 1st line of defense

Produces lactic acid in sweat and fatty acid in the sebaceous secretions

Respiratory tract does what in the 1st line of defense

Sneezing and coughing and mucus and ciliary movement

GI tract does what in the 1st line of defense

Produces gastric acids

Tears, nasal secretions & saliva does what in the 1st line of defense

Produces lysozymes

Sperm does what in the 1st line of defense

Produces spermine and zinc

Vagina does what in the 1st line of defense

Maintains an acidic environment

Phagocytosis

Process of engulfing or eating up microbes

Opsonization

Process of making a pathogen for ingestion by a phagocyte

Opsonins

Any molecule that binds to the antigen and thereby enhances the binding of phagocytes to the pathogens

Macrophage

a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.

Macrophages in the lung

Alveolar Macrophages

Macrophages in the liver

Kuppfer Cells

Macrophages in the Brain

Microglia

Macrophages in the Bones

osteoclasts

Macrophages in the connective tissues

histiocytes

Macrophages in the spleen

sinusoidal cells

Granulocytes

Contain granules seen under a microscope. Neutrophils, eosinophils, basophils

Neutrophils

These polymorphonuclear leukocytes, quickest response, short-lived, dead ones are responsible for pus, effective against bacteria and fungi

Neutropenia

Decreased Neutrophil, which can lead to agranulocytosis (severely low levels)

Eosinphils

1-4% of WBCs, in the respiratory and GI tract, ineffective phagocyte, effective against parasites and hypersensitivity.

Basophils

0.5-1% of WBCs, least common granulocytes, similar to mast cells: contains histamine and heparin, plays a role in parasitic and allergic reactions.

Dendritic Cells

Similar appearance to dendrites found in the brain, only immature dendritic cells are phagocytes. Mature ones bring antigen to the lymph tissues and present it to the lymphocytes.

Mast Cells

Grave granules containing chemical mediators of inflammation.

Different types of mast cells

histamine, serotonin, leukotrienes, prostaglandin, heparin, cytokines.

Mast cells are activated by

Direct injury to the mast cells, immunoglobulin E, activated by the compliment system

Functions of inflammation

Prevent additional pathogen entry, slow the spread of pathogens away from the area, mobilize immune response, repair/replace tissue damaged by the injurious agent/byproducts.

Adverse effects of inflammation

Tissue damage: cytokines release causes fever, anorexia, malaise, weight loss and can even cause severe inflammatory response syndrome

Complement System

Composed of 20 proteins found in the serum. Ability of this protein to complement or enhance the effectivity of the antibodies.

C3a function

mast cell and basophil degranulation, vasodilation and increased capillary permeability

C5a function

Mast cell and basophil degranulation, vasodilation and increased capillary permeability, chemotaxis of WBC

C4a function

Mast cell and basophil degranulation

C5b

Opsonization of bacteria

C4b

Opsonization of bacteria

Natural Killer Cells

Able to determine whether a cell is infected or not, no memory of antigen, secrets enzyme which causes cell death, effective against viruses and tumors

Acquired immunity

Stimulated by antigens, slow to start, highly specific, has immunologic memory

T cell mediated immunity

must be in direct contact with their targets.

Killer T-Cell

Affect infected cells and get their antigen from live pathogen

Types of Killer T-Cells

Cytotoxic T-lymphocyte, cytotoc T-cell, Cytolytic T-cell, CD8+

Activation of killer t-cell

Cut up a bacterial protein or antigen, bind it with own protein, and bring it to the cell surface

Clonal Expansion

the process where a single activated immune cell, such as a B cell or T cell, divides and multiplies into a large population of identical daughter cells, all bearing the same antigen receptor

specific Killer T-Cell

Can not kill infected cells that didn’t trigger the response

Memory Killer T-Cells

Gains a faster reaction to the same antigen during a later exposure

Antigen presenting Cells

Fragments of pathogen protein are brought to the surface and binds with macrophage protein

Kiler T-Cells

Fights microorganisms that has invaded