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109 terms

Anatomy CHpt 21 Lymphatic system

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LYMPHATIC SYSTEM
consists of a network of vessels that penetrates nearly every tissue of the body, and a collection of tissues and organs that produce immune cells
lymphatic system functions
fluid recovery, immunity, lipid absorption
fluid recovey
reaxcess fluid absorbs and returns it to the blood. inteference can lead to adema
immunity
pick upsthe foreign cells with lymph nodes, where immune cells stand guard gainst foreign matter. then activate immune response if they encounter any foreigners
lipid absorption
lacteals( lymphatic vessels) absorbs dietary lipid which are not absorb by the blood capillaries
lymphatic system components
lymphatic vessels, lymphatic tissue( Lymphocytes and macrophages), lymphatic organs
lymph
clear, colerless fluid, similar to blood plasma. low in protein
in the lymphatic system
lymph leaving the lymph nodes contains a large number of lymphocytes. it is the main supply of lymphocytes in blood stream (lymph nodes).
lymphatic vessels
where lymph flows. penerate every tissue but are absent in nervous tissue, cartilage, cornea, bone, and bone marrow.
unlike the cells of blood capillaries
lymphatic endothelial cells are not joined by tight junctions and do not have a continuous basal lamina.
when pressure is higher in the lymphatic capillarie than in the tissue fluid
the flaps are pressed outward ( they are closed)
when tissue fluid is high in lympatic capillaries
the flaps are pushed inward ( the open)
route from tissue fluid back to the blood stream:
lymphatic capillaries- collecting vessels- six lymphatic trunks- two collecting ducts-subclavian veins.
lymphatic capillaries
converge to form collecting vessels.
lymph nodes
converge to form lymphatic trunks
lymphatic trunks
grains to major portion the body. their names indicate where the deposit to.
lymphatic trunks
converge to form 2 collecting ducts: lymphatic duct and thoracid duct.
cisterna chyli
section in thoracic duct. where the 2 lumbar meets. have a large amount of chyle(fatty interstial lymph) which it collects after a meal.
lymph flow
have a lower pressure and speed than venous flow. can be produced by skeletal muscles squezzzing lymph nodes
primary mechanism of lymph flow
rhythmic contractions of the lymphatic vessels themselves
Lymphatic cells
Natural killer cells(NK), T Lymphocytes (T cells), B Lymphocytes (B cells), Macrdophages, Dentric cells and Reticular cells.
natural killer cells
large lymphocytes that attack and destroy bacteriatransplanted tissues and host cells that have either become infected with viruses or turned cancerous
T lymphocytes
lymphocys that matures in the thymus and later depend on thymic hormones; T stands for thymus- dependent.
B lymphocytes
lyphocytes that differentiates into plasma cells. they mature in the bone marrow
plasma cells
connective tissue cells that secrete antibodies
Macrophages
very large. they develop from monocytes that have migrated from the blood stream. they phagocytize tissue debris, dead neutrophils and other foreign matter. process foreign matter and display antigenic fragments of it to specific Tcells. This alerts the immune system of the presence of an enemy
dendritic cells
branched, mobile APCs, locaded in the epidermis, mucous menbrane, and lymphatic organs. called langerhans cells in skin.the engulf matter by by receptor meiated phagocytosis. migrate to nearby lymph node after initializing an antigen and activates immune reactions.
reticular cells
braned. statiaonary APC that contributes to the connective tissue framework of lymphatic organs
lymphatic tissues
are aggregations of the lymphocytes in the connective tissues of mucous menbrane and various organs.
diffuse lymphatic tissue
type of lymphatic tissue in which lymphocytes are scatered rather than densely clustered
mucosa-associated lymphatic tissue
types of lymphatic tissue where there is mucous menbrane. EX respiratory, digestive, urinary, and reproductive track
lymphatic nodules
lymphocytes and macrophages. they come and go as pathogens invaded the tissues and the immune system answers the challenge.
lymphatic organs
limphoids. red marrow, thymus, lymph nodes, tonsils and spleen.
primary lymphatic organs
red bone marrow and thymus. the cite of the B an T lymphocytes.
B and T Lymphocytes
will become immunocompetent and are able to recognize and respond to antigens
secondary lymphatic organs
lymph nodes, tonsils, and spleen immunocompent lymphocytes will migrate to these organs after they mature in the primary organs
bone marrow
2 types red and yellow. yellow is fat. red bone marro where hemopoiesis and immunity occurs.
thymus
menber of endocrne, lymphatic and immune systems . secrete homones. it's lobules has a central medulla housed by T cells and the cortex is housed by reticular epithelial cells
reticular cells
form blood-thymus barrier, produces signaling molecules that promote the development and action of T cells, including thymosins, thymopoetin, thymulin, interleukins, and interferon.
lymph nodes
serve 2 funtions: cleanse the lymph and act as a site of T and B cell activation. common site of metastatic cancer
germinal centers
acquired when lymph node is fighting pathogen. and the cite where B cells mmultiply and differentiate in to plasma cells.
spleen
body's largest lymphatic organ
red pulp in spleen
consist of sinus gorged with erythrocytes
white pulp spleen
have lymphocytes and macrophages
pathogens
viruses, bacteria, fungi and other microbes tha can cause diseases
number of body line defenses
3
first line of defense
exterbal barriers: skin and mucous menbrane
second line of defense
leukocytes and macrophages antibacterial proteins, immune surveillance, anflammation and fever. against pathogen that cross first line of dense
third line of defense
immune sytem which defeats pathogens and leaves a memory
acid mantle in sweat
thin film of lactic acid that inhibits bacterial growth
dermicidins
a sweat antibacterial protein
defensins and cathelicidins
peptides produced by keratinocytes, neutriphils, and macrophages that destroy bacteria virus and fungi. enhance by vitamin D
lysozyme
enzyme that destroy bacteria by destroying their celll walls
the five types of leukocytes
neutrophils, Eosinophils basophils, lymphocytes and Monocytes
neutrophils
wanders in connective tissues to kill bacteria.kill by sime phagocytosis and digestion. has a respiratory burst that forms two defenses: hydrogen peroxide and hypochlorite; these chemicals form a killing zone arround the neutrophil. can damage host connective tissue and sometimes contributes to rheutmatoid arthritis
eosinophils
found in the mucous menbrane. standing against parasites, allergens and other foes. secrete enzymes that degrade and limit the action of histamine inflammatory chemicals that can cause damage.
basophils
secrete chemicals that aid the motility of other leukocytes
mast cells
types of connective tissue cell similar to basophils
lymphocytes
NK cell, T-cell, B-cells
Monocytes
leukocytes that emigrate from blood into connective tissues and transforms into macrophages
macrophage system
all of the body's phagocytotic cells except leukocytes
interferons
proteins from an infected cell that alert other cells and protect non infected cells from becoming infected. also activates NK cells and macrophages to desroy infected cells to they don't replicate viruses and cancer cells.
complement system
a goupr of 30 or more globulins that make powerful contribution to both nonspecific resistance and specific immunity. complete actions of antibody. produced by the liver
activated complement contributes to pathogens destructions by four methods:
inflammation, immune clearance, phagocytosis, and cytolysis
pathways of activation to complement system:
classical , alternative , lectin
classical pathway
require antibody- antigens complexes form on pathogen suface;then it set off reaction cascade( complement fixation)
alternatve pathway
requires no antivbody.belong to nonspecific defenses. C3 dissociates into fragments C3a and C3b then C3b binds to pathogen surface. Next, reaction cascade and autocatalytic effect.
Lectin Pathway
antibody independent. belong to nonspecific defenses. binds to carbohydrates on pathogen surface and causes reaction cascade
inflammation method
C3a stimulates mast cells and basophils to secrete histamine and other inflammatory chemicals. also activates neutrophils and macrophages
clearance method
C3b binds Ag---Ab complexes to RBCs. as the RBCs circulate through the liver and pleen, the macrophages of these organs destroys the Ag---Ab complexes. principal means of clearing foreign antigens from the blood stream
phagocytosis method
cell eating. pathogens are digested by neutrophils and macrophages.
Cytolysis method
cell drinking.all the Cs are bind up to 17 molecules to form a menbrane attack complex. then complex forms a hole in target cell. water and electrolytes leaks out and cell ruptures
immune suveillance
phenomenom in which NK cells continually patrols the body for pathogens and disease host cells.
granzymes
NK's group of protein-degrading enzymes
perforins
Nk's kiss of death. that make a hole in target cell wich allows a rapid inflow of water and salts
fever
pyrexia
aspirin
antipyreptic medicine
advantages of a fever
promotes inteferon activiies, elevate metabolic rate, accelerates tissue repair and inhibits reproduction of bacteria
exogens pyrogens
fever- producing agents. like the surfaces glycolipids of bacteria and viruses.
endogenous pyrogens
produced by neutrophils and macrophages to attack fever producing agents
cytokine
small proteins that serves as a chemical communication network among immune cells
hyperemia
increalood increasing blood flow beyond normal
selectins
cell-adhesion molecules
bradykanin
stimulates pain receptors.
pus
dead cells other tissues debris that form a pool of yellowish fluid.
monocytes and tissue repair relation
monocytes are major agents of tissue clean up and repair
abscess
cavity where pus is acumulates
2 types of immunity non specific resistance:
Specifity and Memory
Specificity
immunity is directed against a particular pathogen
memory
when reexposed to same pathogen, the body reaccts so quickly that there is no noticeable illness.
types of cell immunity
cellular(cell-mediated) immunity, humoral (antibody-mediated) immunity: Natural active immunity, artificial active immunity, natural passive immunity, artificial passive immunity.
Natural active immunity
production of host antibodies or T cells as a result of natural exposure to antigen
artificial active immunity
production of host antibodies or T cells as a result of vaccination
natural passive immunity
temporary immunity that results from acquiring antibodies produced by another person. EX: mother to fetus
artificial passive immunity
a temporary immunity that results from injection of an immune serum obtained another person or animal
antigen
amy molecule that triggers an immune response.
epitotes
antigenic determinants. that stimulate immune responses
haptens
stimulate immune response by binding to a host macromolecule and the body recognizes as foreigners.
negative selection
a process where T-cell eliminated
forms of negative selections
clonal deletions and anergy
clonal deletion
self reactive T-cells die and macrophages eat them
anergy
T-cell remain alive but unresponsive
positive selection
T-cells move onto the medulla of thymus and multiply and form clones of identical T cell programmed to respong to a particular antigen
MHC proteins
proteins on the APC surface
cellular immunity 4 classes
cytotoxic T-cells(Tc), Helper T cells, regulatory T-cells, or T-reds, Memory T cells
Cytotoxic T cells
are effectors of cellular immunity that carry out the attack on foreign cells
Helper T cells
helps with the action of Tc cells
Regulatory T Cells
limit the immune system response by inhibiting multiplication and cytokine secretion by other T cells. pevent auto immune disease
Memory T cells
descended from Tc cells and are responsiblee for memory in cellular immunity