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127 terms

Chapter 21 - The Immune System: Innate and Adaptive Body Defenses

This was taken from Pearson's Human Anatomy & Physiology, 8th Edition to help me study for the tests in the class, it is all of the key bold terms. We have an extremely hard teacher who believes that we should know our science inside and out to be good in the medical world so he tests very hard. I hope this helps everyone to study a little bit better
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immunity
(medicine) the condition in which an organism can resist disease
innate defense system
responds immediately to protect the body from all foreign substances, whatever they are
adaptive defense system
Is aquired immunity due to infection or vaccination: Third line of defense mounts attack against particular foreign substances (Takes longer to react than innate system, Workds in conjunction with the innate system)
immune system
a system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response
pathogens
Microbes that cause disease
phagocytes
Cells that use phagocytosis to engulf foreign organisms. The chief ___ are macrophages, created from monocytes.
lysozyme
an enzyme found in saliva and sweat and tears that destroys the cell walls of certain bacteria
neutrophils
A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease.
phagocytosis
process in which phagocytes engulf and digest microorganisms and cellular debris
phagosome
Intracellular vesicle containing material taken up by phagocytosis.
phagolysosome
Intracellular vesicle formed by fusion of a phagosome with a lysosome, in which the phagocytosed material is broken down by degradative lysosomal enzymes.
adherence
process by which phagocytes attach to microorganisms through the binding of complementary chemicals on the cytoplasmic membranes
opsonization
process whereby opsonins make an invading microorganism more susceptible to phagocytosis
respiratory burst
metabolic change accompanied by a transient increase in oxygen consumption that occurs in neutrophils and macrophages when they have taken up opsonized particles. It leads to the generation of toxic oxygen metabolites and other anti-bacterial substances that attack the phagocytosed material.
inflammatory response
nonspecific defense reaction to tissue damage caused by injury or infection
TLRs
This binds pathogens in endosomes which allows epithelial cells to recognize pathogen and produce a transcription factor that turns on expression of inflammatory molecules
mast cells
a vertebrate body cell that produces histamine and other molecules that trigger the inflammatory response.
histamine
amine formed from histidine that stimulates gastric secretions and dilates blood vessels
kinins
acute inflammation; increase vascular permeability, vasodilation, smooth muscle contraction, pain; made in liver
prostaglandins
A group of bioactive, hormone-like chemicals derived from fatty acids that have a wide variety of biological effects including roles in inflammation, platelet aggregation, vascular smooth muscle dilation and constriction, cell growth, protection of from acid in the stomach, and many more.
leukotrienes
potent biological substances produced from unsaturated fatty acids by mast cells that cause bronchospasm, attract inflammatory cells, and induce excessive mucus secretion
complement
one of a series of enzymes in the blood serum that are part of the immune response. (starts with C)
hyperemia
increased blood in an organ or other body part
exudate
material composed of serum, fibrin, and white blood cells that escapes from blood vessels into an area of inflammation
leukocytosis
an abnormal increase in the number of white blood cells in the blood as a result of infection (as in leukemia)
leukocytosis-inducing factors
?? - causes increase in white blood cells
margination
the aggregating or lining up of substances along a surface or edge (eg, the lining up of white blood cells against the wall of a blood vessel during the inflammatory process)
diapedesis
passage of blood cells (especially white blood cells) through intact capillary walls and into the surrounding tissue
chemotaxis
movement by a cell or organism in reaction to a chemical stimulus
Phagocyte Mobilization
-leukocytosis
-inflammed areas release signaling proteins (selectins)
-margination
-diapedesis
-chemotaxis
-monocyte follows neurtrophils,become macrophage with 12hr
pus
a fluid product of inflammation
interferons
Antiviral proteins secreted by T cells
antimicrobial proteins
are short peptides that have a broad spectrum of antimicrobial activity. Besides killing a wide range of microbes, AMPs can attract dendritic cells and mast cells, which participate in immune responses. aka AMPs
compliment system
Group of at least 20 proteins whose activites enhance or complement the body's other defense mechanisms. -destruction of pathogen-enhancement of phagocytosis-stimulation of inflammation
classical pathway
in this pathway:
1. auto antibodies bind to surface of senescent cells
2. macrophages recognize Ab-taged cells and phagocytose them
alternative pathway
less effective, slower activation of complement system; involves absence of antibody molecules.
membrane attack complex
the complex of terminal complement components that forms a pore in the membrane of the target cell, damaging the membrane and leading to cell lysis.
fever
elevated body temperature that occurs in response to infection
pyrogens
molecules that set the body's thermostat to a higher temperature. they are released by certain leukocytes
humoral immunity
specific immunity produced by B cells that produce antibodies that circulate in body fluids. (also called antibody-mediated immunity)
cellular immunity
Type of ACQUIRED IMMUNITY involving T-cell lymphocytes. Large numbers of activated lymphocytes are formed specifically to destroy the foreign agent. This is called what type of immunity?
antigens
foreign substances that trigger the attack of antibodies in the immune response.
nonself
Antigen recognized as foreign by an organism.
complete antigens
antigens that are able to stimulate the proliferation of specific lymphocytes and antibodies and to react with the activated lymphochytes and produced antibodies; can develop antibodies
immunogenicity
ability to stimulate proliferation of specific lymphocytes and antibodies
reactivity
ability to react with the activated lymphocytes and antibodies released by immunogenic reactions.
hapten
small antigen incapable of stimulating antibody production unless attached to a "protein". E.g. ... Penicillin -- (aka. incomplete antigen)
antigenic determinants
otherwise known as epitopes; regions of the antigen that are recognized by immunoglobulin B cell receptors or T cell receptors
self-antigens
A term used to describe all the normal constituents of the body to which the immune system would respond were it not for the mechanisms of tolerance that destroy or inactivate self-reactive B and T cells.
MHC proteins
Major histocompatibility complex; A family of genes that encode a large set of cell surface proteins. Class I and class II molecules function in antigen presentation to T cells. Foreign molecules on transplanted tissue can trigger T cell responses that may lead to rejection of the transplant.
b lymphocytes
form in the bone marrow and release antibodies that fight bacterial infections (aka. b cells)
t lymphocytes
provide cell-mediated immunity and are processed by the thymus gland. (aka. t cells)
immunocompetence
The ability of the body to produce a normal immune response (i.e., antibody production and/or cell-mediated immunity) following exposure to an antigen.
Self-tolerance
The normal situation whereby a person's immune system does not respond to constituents of the person's body.
primary lymphoid organs
bone marrow and thymus
secondary lymphoid organs
sites where mature cells of the immune system encounter, trap, and destroy foreign substances as they invade the body, including the spleen, lymph nodes, and MALT
positive selection
the proliferation of developing thymocytes when they receive the appropriate signals.
MHC restriction
the requirement that immune cells share the same MHC or "self" antigens in order to interact and immunologically respond together
negative selection
destruction of developing thymocytes as a result of strong signals when thymocytes interact with thymic epithelium
somatic recombination
is a genetic recombination which randomly selects and assembles segments of genes encoding specific proteins with important roles in the immune system
antigen-presenting cells
macrophages that break down pathogens and present the antigens so t cells can recognize them.
antigen challenge
First encounter between an immunocompetent by naive lymphocyte and an invading antigen, usually takes place in the spleen or in a lymph node, but it may happen in any secondary lymphoid organ
clonal selection
antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves
clone
a group of genetically identical cells or organisms derived from a single cell or individual by some kind of asexual reproduction
plasma cells
cells that develop from B cells and produce antibodies.
memory cells
B lymphocytes that do not become plasma cells but remain dormant until reactivated by the same antigen.
primary immune response
the initial immune response to an antigen, which appears after a lag of several days
secondary immune response
The adaptive immune response provoked by a second exposure to an antigen. It differs from the primary response by starting sooner and building more quickly.
immunological memory
The capacity of the immune system to make quicker and stronger adaptive immune responses to successive encounters with an antigen. Immunological memory is specific for a particular antigen and is long-lived.
active humoral immunity
involves B cells being exposed to antigen; develops immunological memory, long term protection. Naturally- through infection or contact with pathogen; Artificially- vaccine, dead or attenuated
vaccines
dose of a disabled or destroyed pathogen used to stimulate a long-term immune defense against the pathogen. A weakened form of the virus is given to the person so their immune system can build up immunity to the virus.
passive humoral immunity
received from donor, placental transfer and breast milk, administration of immune serum (antivenom)
antibodies
Specialized proteins that aid in destroying infectious agents. (aka. immunoglobulins "igs")
gamma globulin
a plasma protein containing the immunoglobulins that are responsible for immune responses
antibody monomer
basic structural unit of an antibody, composed of four polypeptides linked by disulfide bonds
H chains
heavy polypeptide chains of antibodies that pair with L chains to form a functional immunoglobulin molecule. The constant end binds to an isotype-specific receptor site of T cells at one end and the variable end on the opposite pole of the immunoglobulin molecule pairs with L chains and binds specifically to antigen on target cells
L chains
Identical to H chains but half as long.
V region
the extracellular amino-terminal region of an immunoglobulin heavy or light chain or a T-cell receptor that contains variable amino acid sequences that are different between every clone of a lymphocyte and that are responsible for specificity for antigen; antigen-binding variable sequences are localized to hypervariable segments; aka variable region
C region
The portion of immunoglobulin (Ig) or T cell receptor (TCR) polypeptide chains that does not vary in sequence among different clones of B and T cells and is not involved in antigen binding. Encoded by DNA sequences in the Ig and TCR gene loci that are spatially separate from the sequences that encode the variable regions.
antigen-binding site
The site on an immunoglobulin or T-cell receptor molecule that binds specific antigen.
secretory IgA
A protein of 70,000 molecular weight fragment of the poly-Ig receptor produced by epithelial cells and attached to the dimer of IgA. It facilitates the passage of IgA through cells and also inhibits the effects of degradative enzymes
immune complexes
defensive mechanisms used by antibodies. (neutralization, agglutination, precipitation, compliment fixation)
neutralization
The mechanism by which antibodies binding to sites on pathogens prevent growth of the pathogen and/or its entry into cells. The toxicity of bacterial toxins can similarly be neutralized by bound antibody.
agglutination
An antibody-mediated immune response in which bacteria or viruses are clumped together, effectively neutralized, and opsonized.
precipitation
soluble molecules are cross-linked into large complexes that settle out the solution. (an immune complex)
complement fixation and activation
chief antibody defensed used against cellular antigens. (an immune complex)
monoclonal antibodies
Antibodies produced by a single clone of B lymphocytes and that are therefore identical in structure and antigen specificity.
hybridomas
Hybrid cell lines that make monoclonal antibodies of defined specificity. They are formed by fusing a specific antibody-producing B lymphocyte with a myeloma cell that grows in tissue culture and does not make any immunoglobulin chains of its own.
CD4 cells
The subset of T cells that express the CD4 co-receptor and recognize peptide antigens presented by MHC class II molecules. See helper CD4 T cells.
helper T cells
T cells that help the immune system by increasing the activity of killer cells and stimulating the suppressor T cells
CD8 cells
The subset of T cells that express the CD8 co-receptor and recognize peptide antigens presented by MHC class I molecules. See cytotoxic T cells.
cytotoxic T cells
T cells that can kill other cells. Almost all cytotoxic T cells are CD8 T cells. Cytotoxic T cells are important in host defense against viruses and other cytosolic pathogens, because they recognize and kill the infected cells.
Class I MHC proteins
Found on virtually all body cells
endogenous antigens
molecules produced by cells invaded by a virus and places on the cell membrane of the infected cell. stimulates T cells to produce clones of killer cells and memory cells
Class II MHC proteins
protein found only on the surface of B lymphocytes, macrophages, and dendritic cells that serves as a reference point for self (looked for by T helper cells)
T Cell Activation
The stimulation of mature naive T cells by antigen presented to them by professional antigen-presenting cells. It leads to their proliferation and differentiation into effector T cells.
Antigen Binding
First step of T Cell Activation, caused by T cell antigen receptors binding to an antigen-MHC complex on the surface of an APC.
co-stimulation
Antigen recognition by helper T cell induces the expression of CD40L. CD40L binds to CD40 on the APC and stimulates the expression of B7 molecules which bind to CD28 on the helper T cell and the secretion of cytokines that activate the helper T-Cell
anergy
reduction or lack of an immune response to a specific antigen
cytokines
chemicals released by T helper cells that stimulate B cells
interleukin 1 & 2
A cytokine secreted by a macrophage that is in the process of phagocytizing and presenting antigen. It in combination with the antigen, activates the helper T cell to produce IL2 and other cytokines.
T cell-independent antigens
CHO not processed like protein
-no T cell activation, no memory T cells
macrophage can't engulf CHO capsule unless opsonized by Ab (protective- hard to make Ab to CHO)
-infants under 2-> no T cell independent (susceptible to capsular pathogens)
T cell-dependent antigens
Most antigens require Helpter T Cells co-stimulation to activate B cells. These are called:
cytotoxic T cells
T cells that can kill other cells. Almost all cytotoxic T cells are CD8 T cells. Cytotoxic T cells are important in host defense against viruses and other cytosolic pathogens, because they recognize and kill the infected cells.
lethal hit
Tc kill the enemy directly; TH cells will stimulate other immune cells
perforins
Chemicals secreted by certain lymphocytes that create holes in the membrane of a host cell which causes the host cell to swell and rupture
granzymes
a protein-degrading enzyme secreted by the bound NK cell which enters the pore made by the perforins. Inside the enemy cell, the granzymes destroy cellular enzymes and induce apoptosis (programmed cell death)
Fas receptor
a receptor on the outside of a MHC class 1 is what?
immune surveillance
NK cells continually patrol the body "on the lookout" for pathogens or diseased host cells. They attack and destroy bacteria, cells of transplanted organs and tissues, cells infected with viruses and cancer cells.
regulatory T Cells
Antigen-specific CD4 T cells whose actions can suppress immune responses.
autografts
tissue transplanted from one site to another on the same person
isografts
tissue grafts from an identical person (identical twin)
allografts
tissue taken from an unrelated person
xenografts
tissue taken from a different animal species
immunodeficiency
immunological disorder in which some part of the body's immune system is inadequate and resistance to infectious diseases is reduced
SCID
a congenital disease affecting T cells that can result from a mutation in any one of several different genes. (Severe combined immunodeficiency)
AIDS
a serious (often fatal) disease of the immune system transmitted through blood products especially by sexual contact or contaminated needles (Acquired immune deficiency syndrome)
HIV
the virus that causes acquired immune deficiency syndrome (AIDS)
autoimmunity
production of antibodies against the tissues of your own body
autoimmune disease
any of a large group of diseases characterized by abnormal functioning of the immune system that causes your immune system to produce antibodies against your own tissues
hypersensitivites
immune responses to a perceived threat; causes tissue damage
immediate hypersensitivities
begin almost immediately after contact with allergen
allergies
overreaction of the immune system to antigens
allergen
any substance that can cause an allergy
anaphylactic shock
a severe and rapid and sometimes fatal hypersensitivity reaction to a substance (especially a vaccine or penicillin or shellfish or insect venom) to which the organism has become sensitized by previous exposure
allergic contact dermatitis
TYPE IV Hypersensitivity reaction, follows exposure to allergen. Lesions occur at the site of contact.
delayed hypersensitivity
reaction takes about 1-3 days to occur and may take weeks to go away; examples include deoderants, cosemetics and metals