Lecture 10b:Immune System
DefinitionsImmunity- the body’s ability to repel ordestroy foreign substances, pathogens,and cancer cellsAntigen- any mole...
BasicsImmune system consists of lymphatic organs plusindividual cells   Red bone marrow   Thymus gland   Lymph nodes   Spl...
Red Bone MarrowProduces all types of blood cellsLymphocytes (WBC’s) of two types    B cells- Produce plasma cells and memo...
Thymus Glandlargest in children; gets smaller whenwe ageT cells mature hereOnly ones that do not attack ‘self’ cellsare re...
Lymph NodesOccur along lymphatic vesselsfilter lymph as it passes through sinuses -open spaces in the nodeMacrophages line...
SpleenFilters the bloodContains red pulp- where macrophagesremove debris (ie dead cells) and pathogensContains white pulp-...
Non-Specific ImmunityFirst line of defense against mostpathogensConsists of:  Barriers to entry  Inflammatory Response  Co...
Barriers to EntrySkin and mucous membranes serve as a mechanicalbarrierOil gland secretions on skin have some antibiotic e...
Inflammatory ResponseResponse to damaged tissue- outwards signs of redness,swelling, pain, warmthInjury starts a chain rea...
Inflammatory Response4. Neutrophils migrate to the site of injury- these areameboid WBCs that phagocytize http://www.scien...
Complement SystemConsists of blood plasma proteinsAssist, mediate, or increase severaldifferent types of cellsMay increase...
Natural Killer CellsKill virus infected or cancerous cells bycell-to-cell contactKill cells that do not have a ‘self’ prot...
Specific ImmunitySpecific defenses respond to antigensImmunity is when the body can recognizeand destroy a specific antige...
B CellsEach B cell can only bind to one specific antigen- occurs ona plasma membrane receptor (BCR)When the antigen binds ...
AntibodiesOnce antibodies are released into thelymph and blood circulation, they bindto the antigensThe complex is then ph...
T CellsT cells have receptors in the membranealso, but they can not recognize anantigen by themselvesAn antigen presenting...
T CellsCytotoxic T cells bind to the target cell, and releaseperforins that create pores in itThen they release granzymes ...
ImmunizationsExposure to some diseases can lead to life-long immunity, but not allIf it is possible, a vaccine is typicall...
ProblemsAllergiesImmediate: caused by the allergenbinding to mast cells that releasehistamines, causing an immune response...
ProblemsAutoimmune disease- when the bodydoes not recognize ‘self’ and attacks itsown cells  Many examples, including MS, ...
ProblemsHIV/AIDS  HIV destroys helper T cells  Because T cells promote all the other cells in the  immune system, once the...
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10b; immune system

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  • 10b; immune system

    1. 1. Lecture 10b:Immune System
    2. 2. DefinitionsImmunity- the body’s ability to repel ordestroy foreign substances, pathogens,and cancer cellsAntigen- any molecule that stimulates animmune responseAntibody- a molecule that recognizes andbinds to a specific antigen, neutralizing it
    3. 3. BasicsImmune system consists of lymphatic organs plusindividual cells Red bone marrow Thymus gland Lymph nodes SpleenNonspecific immunity- against pathogens in generalSpecific immunity- against a specific antigen
    4. 4. Red Bone MarrowProduces all types of blood cellsLymphocytes (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. 5. Thymus Glandlargest in children; gets smaller whenwe ageT cells mature hereOnly ones that do not attack ‘self’ cellsare released ~5%
    6. 6. Lymph NodesOccur along lymphatic vesselsfilter lymph as it passes through sinuses -open spaces in the nodeMacrophages line the sinuses- these are cellsthat engulf and devour pathogensLymph nodes also contain many lymphocyesSwell when fighting infection
    7. 7. SpleenFilters the bloodContains red pulp- where macrophagesremove debris (ie dead cells) and pathogensContains white pulp- where lymphocytesfight infection and cancerYou can live without a spleen, but are moresusceptible to infection
    8. 8. Non-Specific ImmunityFirst line of defense against mostpathogensConsists of: Barriers to entry Inflammatory Response Complement System Natural Killer Cells
    9. 9. Barriers to EntrySkin and mucous membranes serve as a mechanicalbarrierOil gland secretions on skin have some antibiotic effectsUpper respiratory tract has ciliated cells- the cilia movemucous and trapped particles up out of the throatconstantlyStomach has very acidic pHNormal symbiotic bacteria limit or prevent growth ofanything else
    10. 10. Inflammatory ResponseResponse to damaged tissue- outwards signs of redness,swelling, pain, warmthInjury 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. 11. Inflammatory Response4. Neutrophils migrate to the site of injury- these areameboid WBCs that phagocytize http://www.sciencefriday.com/videos/watch/103315. Macrophages also migrate to the site of injury-stimulate production and release of many WBCs fromnearby bone marrow6. Accumulation of dead and living WBCs, as well asdead cells, can form pus7. Macrophages that have been at the site also migrate tothe lymph nodes, to activate the body’s immune response
    12. 12. Complement SystemConsists of blood plasma proteinsAssist, mediate, or increase severaldifferent types of cellsMay increase production of some typesof WBCs
    13. 13. Natural Killer CellsKill virus infected or cancerous cells bycell-to-cell contactKill cells that do not have a ‘self’ protein,which cancerous and virus infected cellscan loose
    14. 14. Specific ImmunitySpecific defenses respond to antigensImmunity is when the body can recognizeand destroy a specific antigenLymphocytes recognize an antigen becausethey have membrane proteins that bind to theantigenB cells and T cells are the cells involved inthis part of the immune system
    15. 15. B CellsEach B cell can only bind to one specific antigen- occurs ona plasma membrane receptor (BCR)When the antigen binds to it, the B cell divides and produces Plasma and memory cellsPlasma cells then manufacture mass amounts of theantibody and secrete it into the body- the antibody isidentical to the BCRMemory cells are how long-term immunity is achieved If the antigen is encountered again, the memory cells divide and produce plasma cells
    16. 16. AntibodiesOnce antibodies are released into thelymph and blood circulation, they bindto the antigensThe complex is then phagocytized, oreliminated from the body
    17. 17. T CellsT cells have receptors in the membranealso, but they can not recognize anantigen by themselvesAn antigen presenting cell must show itto them firstTwo types of T cells: helper and cytotoxic
    18. 18. T CellsCytotoxic T cells bind to the target cell, and releaseperforins that create pores in itThen they release granzymes into the target cell, whichcause it to undergo aptoptosis and dieHelper T cells regulate immunity- have the ability tostimulate cytotoxic T cells and B cells by releasingcytokines These are the primary cells that HIV infects, leading to the body not being able to respond properly to infections
    19. 19. ImmunizationsExposure to some diseases can lead to life-long immunity, but not allIf it is possible, a vaccine is typicallypossibleVaccines usually made either from a deadpathogen or part of it, or frequently fromjust an antigen that is found on thepathogen
    20. 20. ProblemsAllergiesImmediate: caused by the allergenbinding to mast cells that releasehistamines, causing an immune responseDelayed: poison ivy, etc.- probably causedby memory T cells that are at the site ofcontact with the allergen
    21. 21. ProblemsAutoimmune disease- when the bodydoes not recognize ‘self’ and attacks itsown cells Many examples, including MS, lupus, rheumatoid arthritis No cures for these, some drugs can help
    22. 22. ProblemsHIV/AIDS HIV destroys 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

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