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Similar to 10b; immune system
10b; immune system
- 1.
- 2. Definitions Immunity- the body’sability to repel or destroy foreign substances, pathogens, and cancer cells Antigen- any molecule that stimulates an immune response Antibody- a molecule that recognizes and binds to a specific antigen, neutralizing it
- 3. Basics Immune system consistsof lymphatic organs plus individual cells Red bone marrow Thymus gland Lymph nodes Spleen Nonspecific immunity- against pathogens in general Specific immunity- against a specific antigen
- 4. Red Bone Marrow Producesall types of blood cells Lymphocytes (WBC’s) of two types B cells- Produce plasma cells and memory cells plasma cells- produce antibodies memory cells- retain ability to produce antibodies in the future T cells- produce cytotoxic T and helper T cells cytotoxic T- Kill virus infected and cancer cells helper T- regulate immunity
- 5. Thymus Gland largest inchildren; gets smaller when we age T cells mature here Only ones that do not attack ‘self’ cells are released ~5%
- 6. Lymph Nodes Occur alonglymphatic vessels filter lymph as it passes through sinuses - open spaces in the node Macrophages line the sinuses- these are cells that engulf and devour pathogens Lymph nodes also contain many lymphocyes Swell when fighting infection
- 7. Spleen Filters the blood Containsred pulp- where macrophages remove debris (ie dead cells) and pathogens Contains white pulp- where lymphocytes fight infection and cancer You can live without a spleen, but are more susceptible to infection
- 8. Non-Specific Immunity First lineof defense against most pathogens Consists of: Barriers to entry Inflammatory Response Complement System Natural Killer Cells
- 9. Barriers to Entry Skinand mucous membranes serve as a mechanical barrier Oil gland secretions on skin have some antibiotic effects Upper respiratory tract has ciliated cells- the cilia move mucous and trapped particles up out of the throat constantly Stomach has very acidic pH Normal symbiotic bacteria limit or prevent growth of anything else
- 10. Inflammatory Response Response todamaged tissue- outwards signs of redness, swelling, pain, warmth Injury starts a chain reaction of events: 1. Damaged cells and mast cells release chemicals (ex. histamine) 2. Capillaries dilate and become more permeable 3. Excess blood flow and permeability leads to warmth and redness, swelling due to more fluids leaking out of caps. Swelling pushes on nerve endings, causing pain
- 11. Inflammatory Response 4. Neutrophilsmigrate to the site of injury- these are ameboid WBCs that phagocytize http:// www.sciencefriday.com/videos/watch/10331 5. Macrophages also migrate to the site of injury- stimulate production and release of many WBCs from nearby bone marrow 6. Accumulation of dead and living WBCs, as well as dead cells, can form pus 7. Macrophages that have been at the site also migrate to the lymph nodes, to activate the body’s immune response
- 12. Complement System Consists ofblood plasma proteins Assist, mediate, or increase several different types of cells May increase production of some types of WBCs
- 13. Natural Killer Cells Killvirus infected or cancerous cells by cell-to-cell contact Kill cells that do not have a ‘self’ protein, which cancerous and virus infected cells can loose
- 14. Specific Immunity Specific defensesrespond to antigens Immunity is when the body can recognize and destroy a specific antigen Lymphocytes recognize an antigen because they have membrane proteins that bind to the antigen B cells and T cells are the cells involved in this part of the immune system
- 15. B Cells Each Bcell can only bind to one specific antigen- occurs on a plasma membrane receptor (BCR) When the antigen binds to it, the B cell divides and produces Plasma and memory cells Plasma cells then manufacture mass amounts of the antibody and secrete it into the body- the antibody is identical to the BCR Memory cells are how long-term immunity is achieved If the antigen is encountered again, the memory cells divide and produce plasma cells
- 16. Antibodies Once antibodies arereleased into the lymph and blood circulation, they bind to the antigens The complex is then phagocytized, or eliminated from the body
- 17. T Cells T cellshave receptors in the membrane also, but they can not recognize an antigen by themselves An antigen presenting cell must show it to them first Two types of T cells: helper and cytotoxic
- 18. T Cells Cytotoxic Tcells bind to the target cell, and release perforins that create pores in it Then they release granzymes into the target cell, which cause it to undergo aptoptosis and die Helper T cells regulate immunity- have the ability to stimulate cytotoxic T cells and B cells by releasing cytokines These are the primary cells that HIV infects, leading to the body not being able to respond properly to infections
- 19. Immunizations Exposure to somediseases can lead to life- long immunity, but not all If it is possible, a vaccine is typically possible Vaccines usually made either from a dead pathogen or part of it, or frequently from just an antigen that is found on the pathogen
- 20. Problems Allergies Immediate: caused bythe allergen binding to mast cells that release histamines, causing an immune response Delayed: poison ivy, etc.- probably caused by memory T cells that are at the site of contact with the allergen
- 21. Problems Autoimmune disease- whenthe body does not recognize ‘self’ and attacks its own cells Many examples, including MS, lupus, rheumatoid arthritis No cures for these, some drugs can help
- 22. Problems HIV/AIDS HIVdestroys helper T cells Because T cells promote all the other cells in the immune system, once they are too few in number Pretty much any pathogen/ cancer can take hold Death results from the secondary diseases that the person is unable to fight