Term
| Functions of Lymphatic System |
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Definition
Immunity
Lipid absorption
Fluid recovery
(absorbs plasma proteins and fluid (2 to 4 L/day) from tissues and returns it to the bloodstream) |
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Definition
| clear, colorless fluid, similar to plasma but much less protein |
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Definition
tethered to surrounding tissue by protein filaments
endothelial cells loosely overlapped
closed at one end
creates valve-like flaps that open when interstitial fluid pressure is high, and close when it is low |
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Definition
| course through many lymph nodes |
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Definition
| drain major portions of body |
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Definition
| receives lymph from R arm, R side of head and thorax; empties into R subclavian vein |
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Definition
| larger and longer, begins as a prominent sac in abdomen called the cisterna chyli; receives lymph from below diaphragm, L arm, L side of head, neck and thorax; empties into L subclavian vein |
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Definition
Moved along by rhythmic contractions of lymphatic vessels
flows at low pressure and speed
aided by skeletal muscle pump
Valves prevent backward flow
flowing blood in subclavian veins, draws lymph into it |
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Definition
mature in thymus
cell to cell interactions destroy pathogens throughout the body |
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Definition
| activation causes proliferation and differentiation into plasma cells that produce antibodies |
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Term
| Natural killer (NK) cells |
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Definition
| responsible for immune surveillance by destruction of foreign cells |
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Definition
macrophages (from monocytes)
dendritic cells (in epidermis, mucous membranes and lymphatic organs)
reticular cells (also contribute to stroma of lymph organs) |
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Definition
lymphocytes in mucous membranes and connective tissue (CT) of many organs
Mucosa-Associated Lymphatic Tissue |
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Term
| Mucosa-Associated Lymphatic Tissue |
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Definition
| MALT): prevalent in passages open to exterior |
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Term
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Definition
dense oval masses of lymphocytes, congregate in response to pathogens
Peyer patches |
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Term
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Definition
| more permanent congregation, clusters found at junction of small to large intestine |
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Definition
site where T and B cells become immunocompetent
red bone marrow and thymus |
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Definition
site where T and B cells become immunocompetent
red bone marrow and thymus |
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Term
| Secondary lymphatic organs |
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Definition
immunocompetent cells populate these tissues
lymph nodes, tonsils, and spleen |
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Term
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Definition
- only organs that filter lymph
the capsule arises trabeculae, which divides node into compartments containing stroma (reticular ) and parenchyma (lymphocytes and Antigen Presenting Cells) subdivided into cortex (lymphatic nodules) and medulla |
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Definition
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Term
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Definition
| swollen, painful node responding to foreign antigen |
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Definition
Reticular epithelial cells
form blood thymus barrier in cortex
isolates developing T lymphocytes from foreign antigens
secretes hormones (thymopoietin, thymulin and thymosins)
to promote development and action of T lymphocytes
large in fetus |
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Term
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Definition
red pulp/white pulp
functions:
blood production in fetus
blood reservoir
RBC disposal
immune reactions: filters blood, quick to detect antigens |
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Definition
sinuses filled with erythrocytes
spleen |
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Definition
lymphocytes, macrophages; surrounds small branches of splenic artery
spleen |
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Definition
Nonspecific defenses which are broadly effective, no prior exposure necessary
first line of defense
external barriers
second line of defense
phagocytic cells, antimicrobial proteins, inflammation and fever |
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Definition
Specific defenses which result from prior exposure, protects against only a particular pathogen
third line of defense
“the immune system” |
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Term
| First line of defense:skin |
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Definition
toughness of keratin
dry and nutrient-poor
defensins: peptides, from neutrophils attack microbes
lactic acid (acid mantle) is a component of perspiration |
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Term
| First line of defense: mucous membranes |
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Definition
stickiness of mucus
lysozyme: enzyme destroys bacterial cell walls |
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Term
| First line of defense: Subepithelial areolar tissue |
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Definition
tissue gel: viscous barrier of hyaluronic acid
hyaluronidase: enzyme used by pathogens
to spread |
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Term
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Definition
Phagocytize and kill bacteria
degranulation
lysosomes discharge into tissue fluid
respiratory burst
toxic chemicals are created (O2.-, H2O2, HClO) |
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Term
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Definition
Phagocytize antigen-antibody complexes
Antiparasitic effects (tapeworms, roundworms)
Promote action of basophils, mast cells
Enzymes block excess inflammation, limit action of histamine (allergic responses) |
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Definition
Aid mobility and action of WBC’s by secretion of two chemicals
histamine+heparin |
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Definition
(vasodilator)
increases blood flow to infected tissue which delivers leukocytes to the area
EOSINOPHILS |
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Definition
(anticoagulant)
prevents immobilization of phagocytes |
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Term
| Natural Killer (NK) Cells |
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Definition
Large Granular Lymphocytes (LGL’s)
not lymphocytes though
Release Perforins which form a hole
in target cell and release cytotoxic granules
called Granzymes into the cell and kills it |
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Term
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Definition
Secreted by certain cells invaded by viruses
diffuse to neighboring cells and stimulate them to produce antiviral proteins
activate natural killer cells, T cells and macrophages |
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Term
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Definition
enhanced inflammation
phagocytosis
promoted by opsonization
cytolysis
membrane attack complex forms on target cell
immune clearance
RBCs carry Ag-Ab complexes to macrophages in liver and spleen |
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Term
classical pathway
(complment system) |
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Definition
| requires antibody; specific immunity |
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Term
alternate pathway
(complement system) |
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Definition
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Term
| lectin pathway (complement system) |
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Definition
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Definition
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Term
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Definition
| Complement proteins form ring in plasma membrane of target cell causing cytolysis |
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Definition
DNA is degraded and packaged and cell dies
also known as “programmed cell death” or “cellular suicide” |
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Definition
limits spread of pathogens, then destroys them
removes debris
initiates tissue repair |
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Term
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Definition
small proteins regulate inflammation and immunity; include
interferons, interleukins, tumor necrosis factor, and chemotactic factors |
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Definition
redness (erythema) caused by hyperemia ( blood flow)
swelling (edema) caused by capillary permeability and filtration
heat caused by hyperemia
pain caused by inflammatory chemicals (bradykinin, prostaglandins) secreted by damaged cells, pressure on nerves |
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Term
| margination (leukocyte deployment) |
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Definition
| selectins cause leukocytes to adhere to blood vessel walls |
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Term
diapedesis (emigration)
(leukocyte deployment) |
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Definition
| leukocytes squeeze between endothelial cells into tissue space |
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Definition
promotes interferon activity
accelerating metabolic rate and tissue repair
inhibiting pathogen reproduction
105F may cause delirium, 111F- 115F, coma-death |
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Term
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Definition
cytokine
pyrogen
secreted by macrophages, stimulates anterior hypothalamus to secrete PGE which resets body thermostat higher |
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Term
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Definition
Specificity Memory
Cellular immunity
Humoral defense |
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Term
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Definition
| (cell-mediated) via T-Cells. Attack fungi, parasites, viruses, cancer cells and foreign tissue. |
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Term
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Definition
| (antibody-mediated) with B-cells. B-cells become plasma cells, leave the nodes and produce antibodies (Ig’s). Attack bacteria and viruses. |
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Term
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Definition
(produces memory cells)
production of one’s own antibodies or T cells as a result of infection or natural exposure to antigen |
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Term
| Artificial active immunity |
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Definition
(produces memory cells)
production of one’s own antibodies or T cells as a result of a vaccination |
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Definition
(through placenta, milk)
temporary, fetus acquires antibodies from mother |
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Term
| Artificial passive immunity |
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Definition
(snakebite, rabies, tetanus)
temporary, injection of immune serum (antibodies) |
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Term
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Definition
Trigger an immune response
proteins, polysaccharides, glycoproteins, glycolipids
Epitopes |
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Term
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Definition
(antigenic determinants)
stimulate immune responses |
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Term
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Definition
| too small, host macromolecule must bind to them to stimulate initial immune response |
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Term
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Definition
depends on activities of two general classes of lymphocytes
B-Cells
T-Cells |
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Term
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Definition
Arise from stem cells in red bone marrow
Mature in thymus
naïve T cells colonize lymphatic tissue and organs |
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Term
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Definition
| stimulate maturing T cells to produce antigen receptors |
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Term
| T-Cell Maturation in Thymus |
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Definition
thymic hormone secreted by reticular epithelial (RE) cells stimulate them to develop surface antigen receptors.
“tested” to see if they recognize self antigens and MHC antigens |
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Term
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Definition
T-cells that recognize either self or MHC antigens are eliminated
clonal deletion (destruction) or anergy (they remain alive but are non responsive). |
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Term
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Definition
T-cells that have “passed” (only 2% graduate!) the test now move to the thymic medulla
and form clones of T-cells with varying antigenic specificity. |
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Term
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Definition
development (Bone marrow)
other fetal stem cells remain in bone marrow
B cells should not react to self antigens
or suffer clonal deletion or anergy |
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Term
| Antigen-Presenting Cells (APCs) |
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Definition
B cells, macrophages, reticular cells and dendritic cells (special type of macrophage) function as APC’s and display antigens which are combined with MHC proteins on their surface to T cells
When an APC encounters an antigen, it internalizes it by endocytosis, digests it into molecular fragments and displays the relevant fragments (epitopes) in the grooves of the MHC proteins. This is called ‘Antigen Processing” |
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Term
| major histocompatability complex |
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Definition
proteins which are expressed on antigen presenting cells (APC’s
MHC proteins are structurally unique to every person and act as cell “ID” tags |
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Term
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Definition
Chemical messengers between leukocytes
Used by lymphocytes and APCs to communicate |
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Term
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Definition
| T cells attack diseased host tissues or cells invaded by microbes and can “remember” these antigens and prevent from future attack. |
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Definition
| (TC cells) carry out attack |
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Term
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Definition
| (TH cells): help promote TC cell and B cell action and nonspecific defense mechanisms |
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Term
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Definition
| provide immunity from future exposure to antigen |
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Term
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Definition
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Term
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Definition
MHC-I proteins
found on nearly all nucleated body cells
display peptides produced by host cells |
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Term
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Definition
binding of cytotoxic T cells (CD8 cells) to abnormal peptides on MHC-I and
costimulation via a cytokine
triggers clonal selection: clone of identical T cells against cells with same epitope |
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Term
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Definition
role of MHC-II proteins
found only on antigen presenting cells
display only foreign antigens
stimulate helper T cells (CD4 cells) |
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Term
| Attack Phase: Role of Helper T Cells |
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Definition
Secretes interleukins
attract neutrophils, NK cells, macrophages
stimulate phagocytosis
stimulate T and B cell mitosis and maturation |
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Term
| Attack Phase: Cytotoxic T Cells |
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Definition
Only T cells directly attack enemy cells
docks on cell with antigen-MHC-I protein complex
releases perforin, granzymes - kills target cell
interferons - decrease viral replication and activates macrophages
tumor necrosis factor: kills cancer cells |
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Term
| Humoral Immunity (B-Cells) |
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Definition
B cell receptors bind antigen, take in and digest antigen then display epitopes on its MHC-II protein
After costimulation by TH cell, divide repeatedly, differentiate into plasma cells, produce antibodies specific to that antigen
‘tag it’ for destruction
some B cells differentiate into memory cells |
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Term
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Definition
| DNA segments shuffled and form new combinations of base sequences to produce antibody genes |
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Definition
| B cells in lymph nodules rapidly mutate creating new sequences |
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Definition
| : monomer in plasma; dimer in mucus, saliva, tears, milk, intestinal secretions, prevents adherence to epithelia |
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Definition
| monomer; B cell membrane antigen receptor |
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Definition
| monomer; on mast cells; stimulates release of histamines, attracts eosinophils; immediate hypersensitivity reactions |
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Term
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Definition
| monomer; 80% circulating, crosses placenta to fetus, 2 immune response, complement fixation |
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Term
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Definition
| : pentamer, 10% in plasma, 1 immune response, agglutination, complement fixation |
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Term
Neutralization
(humural immunity) |
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Definition
| antibodies mask pathogenic region of antigen |
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Term
Complement fixation
(humural immunity) |
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Definition
| antigen binds to IgM or IgG, antibody changes shape, initiates complement binding; primary defense against foreign cells, bacteria |
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Definition
| antibody has 2-10 binding sites; binds to multiple enemy cells immobilizing them |
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Precipitation
(humoral immunity) |
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Definition
| antibody binds antigen molecules (not cells); creates antigen-antibody complex that precipitates, phagocytized by eosinophil |
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Term
| Type I (acute reaction) hypdersensitivity |
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Definition
| Antibody mediated (IgE), (food allergies, asthma, anaphylaxis) |
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Term
| Type II (antibody-dependent cytotoxic)hypersensitivity |
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Definition
Antibody mediated (IgG, IgM), subacute (blood transfusion reactions, some drug reactions)
binds to antigens on cells; complement activation and lyses or opsonization
may bind to cell surface receptors and either interferes with function or over-stimulate cell |
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Term
| Type III (immune complex) hypersensitivity |
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Definition
Antibody mediated (IgG, IgM), subacute
(autoimmune acute glomerulonephritis and lupus
IgG or IgM form widespread antigen-antibody complexes
Complexes precipitate and trigger intense inflammation
involved in acute glomerulonephritis and in systemic lupus erythematosus |
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Term
| Type IV (delayed) cell mediated, delayed (12 to 72 hr), hypersensitivity |
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Definition
), (allergies to haptens in cosmetics, poision ivy, graft rejection, tuberculosis skin test, insulin-dependent diabetes)
APC’s in lymph nodes display antigens to helper T cells, which secrete interferon and cytokines that activate cytotoxic T cells and macrophages
Cosmetic and poison ivy allergies - haptens
TB skin test |
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Term
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Definition
occurs in sensitized people
allergen caps IgE on mast cells, basophils
release inflammatory chemicals |
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Term
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Definition
most common chronic illness in children
inhaled allergens, histamines, bronchiole constriction |
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Term
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Definition
| bronchiole constriction, dyspnea, vasodilation, shock, death; treatment- epinephrine |
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Definition
invades helper T cells, macrophages and dendritic cells by “tricking” them to internalize viruses by receptor mediated endocytosis
reverse transcriptase (retrovirus), uses viral RNA as template to synthesize DNA, new DNA inserted into host cell DNA, may be dormant for months to years |
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