immune system.txt

utilizes molecules & immune cells to keep body safe from invading organisms, cancer cells & transplanted tissue; not comprised of organs but is a functional system:

non-specific defense system

specific defense system

non-specific - external body membranes (skin and mucosae)

non-specific - antimicrobial proteins, phagocytes & other cells; inhibit spread of invaders and inflammation is most important mechanism:

attacks particular foreign substances; takes longer to react than the innate system:

most abundent white blood cell; become phagocytic on encountering infectious material in tissue:

mechanism of phagocytosis:

inflammatory response:

large non-specific granular lymphocytes; induce apoptosis in cancer cells & virus-infected cells; secrete potent chemicals that enhance the inflammatory response:

cardinal signs of accute inflammation:

inflammatory mediators:

inflammatory chemicals cause:

fluid that contains proteins, clotting factors & antibodies:

functions of the surge of exudate:

steps for phagocyte mobilization:

dead or dying neutrophils, broken down tissue cells, living & dead pathogens that fill a severly infected wound:

sac of pus walled off by collagen fibers, must be drained in order for healing to occur:

when a macrophage engulfs an organism that cannot be broken down:

attack microorganisms directly; hinder microorganisms ability to reproduce:

anti-viral, reduce inflammation, activate macrophages & mobilize Natural Killer cells:

amplifies all aspects of the inflammatory response; kills bacteria & certian other cell types by cell lysis; enhances both nonspecific and specific defenses:

systemic response to invading microorganisms; leukocytes & macrophages exposed to foreign substances secrete pyrogens (reset the body's thermostat upward):

benefits of moderate fever:

antibody-mediated immunity:

cell-mediated immunity:

substances that can mobilize the adaptive defenses & provoke an immune response; most are large, complex molecules not normally found in the body (nonself)

antibody generating:

ability to stimulate proliferation of specific lymphocytes & antibodies:

ability to react with products of activate lymphocytes & antibodies released:

incomplete antigens:

small molecules; not immunogenic by themselves; are immunogenic when attached to body proteins; cause the immune system to mount a harmful attack:

protein molecules (self antigens) on the surface of cells; antigenic to others in transfusions or grafts; are unique to an individual:

able to recognize & bind to a specific antigen:

unresponsive to self antigens so that it doesn't attack it's own cells:

selects T cells capable of binding to self-MHC proteins (MHC restriction):

prompts apoptosis of T cells that bind to self-antigens displayed by self-MHC; ensures self-tolerance (only 2% make it to maturity)

engulf antigens; present fragments of antigens to be recognized by T cells:

major types of APCs:

uses lymphocytes, APCs & specific molecules to identify & destroy nonself substances; depends upon the ability of its cells to recognize antigens by binding to them & communicate w/one another so that the whole system mounts a specific response:

1st encounter between an antigen & a naive immunocompetent lymphocyte; usually occurs in spleen or lymph node; if lymphocyte is a B cell the antigen provokes a humoral (antibody) immune response & antibodies are produced:

B cell is activated when antigens bind to its surface receptors & cross-link them; receptor-mediated endocytosis of cross-linked antigen-receptor complexes occurs; stimulated B cells grows to form a clone of identical cells bearing the same antigen-specific receptors:

clone cells that don't become plasma cells become memory cells; what do they do:

occurs on the 1st exposure to a specific antigen; lag period is 3-6 days; peak levels of plasma antibody are reached in 10 days; antibody levels then decline:

occurs on re-exposure to same antigen; sensitized memory cells respond w/i hours; antibody levels peak in 2-3 days at much higher levels; antibodies bind w/greater affinity; antibody level can remain high for weeks to months:

occurs when B cells encounter antigens & produce specific antibodies against them:

response to a bacterial or viral infection:

response to a vaccine of dead or attenuated pathogens:

spare us the symptoms of the primary response; provide antigenic determinants that are immunogenic & reactive; target only 2 type of helper T cell, so fail to fully establish cellular immunological memory:

antibodies delivered to a fetus via the placenta or to infant though milk:

injection of serum, such as gamma globulin (protection is immediate but ends when antibodies naturally degrade in the body:

first antibody released; potent agglutinating agent; readily fixes & activates complement

monomer or dimer; in mucus and other secretions; helps prevent entry of pathogens:

monomer attached to the surface of B cells; functions as a B cell receptor:

monomer; 75-85% of antibodies in plasma; from secondary to late primary respones; crosses the placental barrier:

monomer active in some allergies & parasitic infections; causes mast cells & basophils to release histamine:

defensive mechanisms used by antibodies:

"plan" of antibody function:

used in pregnancy, STD and rabies test, research and cancer treatment:

becomes helper T cells when activated (call for help/helper cells):

become cytotoxic T cells that destroy cells harboring foreign antigens (destroyer cells):

two types of MHC proteins are important to T cell activation:

displayed by all cells except RBCs; interact w/CD8 cells:

displayed by antigen presenting cells (APC), dendritic cells, macrophages and B cells; interact w/CD4 cells:

endogenous (from within) antigen is a self-antigen in a normal cell; a nonself antigen in an infected or abnormal cell; informs cytotoxic T cells of the presence of microorganisms hiding in cells:

bind with fragments of exogenous antigens that have been engulfed & broken down in a phagolysosome; recognized by helper T cells:

directly attack & kill other cells; activated T cells circulate in blood & lymph & lymphoid organs in search of body cells displaying antigen they recognize:

targets of cytotoxic cells:

from one body site to another in the same person:

between identical twins:

between individuals who aren't identical twins:

from another animal species:

removing the patients bone marrow & transplanting the donors red marrow into the patient; allows the organ to be treated as self instead of foreign; similiar method has been shown to cure HIV infection in 1 case in Europe:

congential & acquired condition that cause immune cells, phagocytes or complement to behave abnormally:

genetic defect; marked deficit in B & T cells; abnormalities in interleukin receptors; defective adenosine deaminase enzyme (ADA); is fatal if untreated:

an acquired immunodeficiency; cancer of the B cells; leads to immunodeficiency by depressing lymph node cells:

cripples the immune system by interfering w/ the activity of helper T cells; characterized by severe weight loss, night sweats & swollen lymph nodes; opportunistic infections occur, including pneumocystis pneumonia & Kaposi's sacroma:

immune system loses the ability to distinguish self from foreign; production of autoantibodies & sensitized TC cells that destroy body tissues:

destroys myelin sheath on neural tissue:

impaired communication between nerves & skeletal muscle:

prompts excessive thryoxine produced by thyroid:

destroys beta cells of the pancreas that produce insulin:

systemic disease that destroys the kidney, heart, lungs and skin:

severe impairment of renal function:

destroys joints of the body:

mechanisms of autoimmune diseases:

immune responses to a perceived threat; causes tissue damage; antibodies cause immediate & subcute hypersensitivites; T cells cause delayed hypersensitivity: