1 Flashcards
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Lymph?
excess tissue fluid carried by lymphatic vessels, this fluid was pushed out by capilarry beds and into tissue spaces
properties of lympatic vessels/lymphatics
1)lymph is a onw way system moving to the heart only
2) milking action of skeletal muscle
3)rhythmic contraction of smooth muscle in vessel walls
4)respirtory pump–pressure changes within thorax
Lymph node structure
most are kidney shaped, less than 1 inch long, & burried in connective tissue that surrounds them
Fibrous capsule
surrounds the lymph node, trabeculae – extend from the capsule dividing the node into compartments
cortex
outer part contains follicles with dark centers called germinal centers that enlarge when generating plasma cells which release antibodies, rest of cortex contains T cells continuously circulate between blood, lymph nodes, lymphatic stream performing hteir surveilence role
follicles
are collections of lymphocytes
medulla
inner part containing phagocytic macrophages
several other organs that contribute to lymphatic function
spleen, thymus gland, tonsils, peyers patches
spleen
1)located on left side of abdomin
2) it filters blood of debris,bacteria, &viruses
3)destroy warn out blood cells and returns some product back to liver
4)forms blood cells in fetus and lymphocytes in adults
5) act as blood resevoir, stores platlets
thymus gland
1) located low in throat
2)functions at peak level only during childhood
3)produces hormones (like thymosin) to program lymphocytes (T cells)
tonsils
1)small masses of lymphoid tissue around pharynx
2) trap and remove foreign material and backteria, protect the throat
3)tonsilities is cuases by congestion with bacteria
peyers patches
1) found in wall of small intestine
2)resemble tonsils in structure
3) capture and destroy bacteria in intestine (machrophages)
non specfic innate body defenses
mechanical barriers to pathogens (skin, mucous membrane, body surface coverings, specialized human cells, chemicals) produced by body
skin and mucous membranes(1)
provide a physical barrier to pforeign matarials (sebum is toxic to bacteria)
stomach mucosa(1)
secretes hydrochloric acid (HCI) and has protein digesting enzymes
saliva &lacrimal fluid contains?(1)
lysozymes: enzymes that destroy bacteria
cells and chemicals
second line of defense
phagocytes
moves by diapedisis to clean up damaged tissues and pathogens (cell debris eating). engluf in vacuole.enzymes from lysomes digest material
Natural killer (NK)
police the body, able to lyse (disenigrate/dissolve cells, kill cancer,destroy virus infected cells), attack cells they DONT recognize release perforins
inflammatory responce
4 most common indicators of acute inflammation – redness, heat, swelling, pain
antimicrobial proteins
attack microorganisms, hinder reproduction of microorganisms
interferon
proteins secreted by virus protected cells, bind to healthy cells to interfear with or hijeack them
fever
hypothalmus heat regulation can be reset by pyrogens – secreated by WBC’s especially macrophages that have been exposed to pathogens
specfic adaptive defesne system
3rd line of defense “immune system”
