Immune System

Immunity

• Innate is the defense system it responds within minutes of the first line of defense
• the second line of defense deals with antimicrobial proteins and phagocytes and inflammation
• Adaptive attacks particular foreign substances its the 3rd line of defense and it takes more time

Immune Sytem Working Together

• many defensive molecules are released and recognized by both systems
• innate response are not specific as one thought and have specific pathways to target certain foreign organisms
• proteins released during innate responses alert cells of the adaptive defense system

Cells

• Phagocytes are Macrophages coming from monocytes that leave the bloodstream; engulf particulate matter
• Natural Killer Cells can lyse and kill cancer cells and virus-infected body cells the can kill by direct contact and cause target cell to undergo apoptosis and secrete potent chemicals
• Cytotoxic T cells are the only T cells that can directly kill other cells they roam in and out of the bloodstream their main target is to target virus-infected cells; bacteria and parasite infected cells; cancer cell; foreign cells
• Regulatory T cells dampen the immune system and used to induce tolerance to transplant tissues

Inflammatory Response

• it is triggered by injury,intense heat,irritating, chemicals, infection
• the function is to prevent the spread of damaging agents and the disposal of cell debris and sets the stage for repair
• there are four short term inflammation signs they are redness,heat,swelling, and pain

Phagocyte Mobilization

• leukocytes are chemicals from injured site attract neutrophils their numbers increase 4-5 times
• Margination are inflamed cells and sprout cells that are adhesion molecules (CAMs) that signal damaged site location to which neutrophils cling
• Diapedesis are chemical signals prompt with neutrophils to flatten out and squeeze out of capillaries
• Chemotaxis are chemicals that migrate to the site of the injury in response to chemicals

Antimicrobial Proteins

• they enhance the innate defenses by attacking microorganisms directly or by hindering their ability to reproduce
• Interferon are small proteins that helped protect cells that have not yet been infected they also block protein synthesis in the virus
• Complement are a group of 20 plasma proteins that circulate in the blood in an inactive form; when they are acativated they kill cells (like bacteria) by the cell lyss

Fever

• is regulated by neurons in hypothalamus
• they can be reset by chemicals called pyrogens
• pyrogens are secreted by leukocytes and macrophages that are exposed to foreign substances in the body
• high fevers are dangerous because proteins are denatured
• mild fevers are beneficial because the liver and the spleen store iron and zinc which is beneficial because iron and zinc become unavailable to bacteria so that they can't multiply

Adaptive Defenses

• they are specific and systematic they are memory- recognizing and previous attacks; then mounts a stronger attack
• there are two types humoral and cellular immunity
• humoral immunity deals with antibody- mediated
• cellular immunity deals with cell-mediated

Humoral Immunity

• are clonal selection and differentiation B cells (B cells are activated)
• stimulated B cell grow and multiplies which equal to clonal slection
• all have the same antigen ( specific receptor on surface of cell membrane)
• all cells descend same cell which is what a clone is also antibodies circulate in blood and lymph

Antibodies

• a blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood.

5 classes of antibodies

• IgM-huge antibody; 1st released to body by plasma cells
• IgA- found in mucus; prevent paathogens from gaining entry into the body
• IgD- always bound to B cells; acts as a receptor
• IgG - most abundant; can cross placentra
• IgE- trouble makers; involved in allergies

Cell- Mediated immune system

• they have T-cells
• there are two type of effector cells: CD4: become helper T cells; CD8: become cyotoxic T cells
• T-cells recognize and respond only fragments of protein antigens displayed on the surface of body cells
• Helper T cells are activate T&B cells; induce proliferation and activate macrophages to become more potent killers

Immunodeficiences

• Is abnormal behavior if immune cells
• SCID is severe combined immunodeficiency syndrome-deficient in B or T cells
• Hodgkin's disease -cancer of B cells
• AIDS- decreased activity of Helper T Cells

Autoimmune Diseases

• -inability to distinguished between self and nonself
• Multiple Sclerosis destroys myelin of white matter of brain and spinal cord
• Graves Disease - thyroid gland to produce excessive amounts of thyroxine
• Type 1 diabetes mellitus destroys prancreatic beta cells-deficient of insulin and inability to use carbhydrates
• Hypersentivities - immune system causes tissue damage as it fights off perceived threat

Sources

• "How Your Immune System Works - HowStuffWorks." HowStuffWorks. N.p., n.d. Web. 13 Mar. 2015.
• "Immune System." Immune System. N.p., n.d. Web. 02 Mar. 2015.
• "Immune System." KidsHealth - the Web's Most Visited Site about Children's Health. Ed. Yamini Durani. The Nemours Foundation, 01 Oct. 2012. Web. 09 Mar. 2015.
• "Importance of the Immune System?" BSI. N.p., n.d. Web. 14 Mar. 2015.