A&P II - Lymph System Well Illustrated Questions And Answers

A&P II - Lymph System Well Illustrated Questions And Answers functions of lymph system - production, maintenance and distribution of lymphocytes distribution of hormones, nutrients and waste products return fluid from tissues to blood where are lymphocytes produced - spleen thymus red bone marrow how do lipids enter blood - lymph system fluid in capillaries - more filtration than reabsorption purpose of more filtration than absorption - maintain normal blood volume eliminate local variation in interstitial fluid where does fluid go from tissues to blood - right subclavian vein organization of lymphatic system - lymphatic vessels lymph lymphatic tissue lymphatic organs where are lymphatic vessels - everywhere except cartilage, cornea, bone, bone marrow lymphatic capillaries origin - blind pockets overlap in lymphatic capillaries - cells not tightly bound, overlap overlap creates valve valve in lymphatic capillaries - permits entry of fluids and solutes prevents their return structure of lymph vessels - tunica externa tunica media tunica intima lymph movement - skeletal muscle pump thoracic pump with inhalation rhythmic contractions of lymphatic vessels with stretch arterial pulsation rapid blood flow in subclavian veins promotes suction of lymph skeletal muscle pump - valves prevent backflow arterial pulsation - lymphatic vessels wrapped in connective tissue with arteries lymph origin - tissues makeup of lymph - clear, colorless fluid left behind from capillary filtration like plasma but low protein lymphocytes function - neutralize or attack pathogens abundancy of lymphocytes - 25-33% what do lymphocytes respond to - invading pathogens abnormal cells (cancer, virus infected cells) proteins secreted by bacteria types of lymphocytes - T lymphocytes B lymphocytes natural killer cells dendritic cells reticular cells what proportion of lymphocytes are T lymphocytes - 80% types of T lymphocytes - helper T cells cytotoxic T cells memory T cells T lymphocyte birth - in red bone marrow from pluripotent stem cells maturation of T lymphocyte - mature in thymus dependent on thymic hormones what proportion of lymphocytes are B lymphocytes - 15% types of B lymphocytes - plasma B cells memory B cells birth of B lymphocytes - bone marrow maturation of lymphocytes - bone marrow natural killer cell function - recognize and destroy abnormal cells what percent of lymphocytes are natural killer cells - 5% dendritic cells - mobile antigen presenting cells (APC) mobile antigen presenting cells - alert immune system to pathogens entering through body surface location of mobile antigen presenting cells - epidermis mucous membranes lymph organs reticular cells - stationary cells in lymphatic organs APCs antigen - any molecule that triggers immune response toxins, part of plasma membrane, cell wall examples of antigens - proteins polysaccharides glycoproteins glycolipids epitope - region of antigen that stimulates immune response amount of epitopes on antigen - one antigen typically has many epitopes function of epitope - stimulate production of different antibodies function of antigen presenting cell - digest antigen fragments activate immune response where are antigen presenting cells displayed - major histocompatibility complex proteins on cell surface own antigens examples of antigen presenting cells - immunocompetent B cells macrophages reticular cells dendritic cells coding of MHC - genes on chromosome 6 MHC proteins - structurally unique to every person except identical twins MHC-I proteins location - nucleated body cells MHC-I proteins - constantly produced and transported to plasma membrane what happens if MHC-I proteins detect normal self-antigens - does NOT elicit T cell response tolerance what happens if MHC-I proteins detect abnormal antigens - trigger T cell response to kill body cell MHC-II protein location - antigen presenting cells when do MHC-II proteins display - foreign antigens types of lymphatic tissue - diffuse lymphatic tissue lymphatic noduels diffuse lymphatic tissue - scattered lymphocytes where is diffuse lymph tissue found - respiratory tract digestive tract urinary tract reproductive tract lymphatic nodules - lymphocytes and macrophages that congregate in large masses not permanent why do lymphatic nodules generate - as immune system to fight pathogens lymphatic organs - connect to lymphatic vessels defined anatomical sites contain many lymphocytes types of lymphatic organs - lymph nodes tonsils thymus spleen red bone marrow where are lymph nodes in the body - neck armpit thoracic cavity abdomen groin popliteal fossa functions of lymph nodes - filter and purify lymph before reaches venous system site of B and T cells activation what is removed from lymph before reaching venous system - 99% of antigens B and T cell activation - fixed macrophages in walls of nodes APCs activate B and T cells lymphadenitis - swollen, painful lymph nodes infection or inflammation of region being drained why do lymph nodes enlarge - increase lymphocyte number attracting phagocytes tonsils - lymph tissue in pharynx tonsillar crypts - pits with lymphocytes function of tonsillar crypts - kill inhaled or swalled pathogens tonsilitis - acute infection of palantine tonsils location of thymus - between sternum and aortic arch what type of organ is the thymus - primary lymphatic organ endocrine organ primary lymphatic organ - place where T cells become immunocompetent what becomes immunocompetent in the thymus - T lymphocytes