淋巴系统解剖

1、CH 23: The Lymphatic SystemGoals1. Discuss the organization of the lymphatic system, including the vessels, principal lymph nodes, thymus, and spleen2. Explain the relationship between the lymphatic and circulatory systems, and the role of lymphoid tissue structures and lymphocytes in the bodys defe

2、nseAccessory to cardiovascular system there are two drainage systemsOverview of the Lymphatic SystemIncludes, vessels, fluid, and nodes or nonsecreting glands. Lymphatic vessels convey fluid from the periphery to the veins. The fluid, lymph (=clear spring water), is what seeps out of the blood at th

3、e peripheral capillaries. Composition is similar to plasma without the proteinsLymphatic organs or tissues (glands) are filtering areas and arenas of lymphocyte maturation and competency.Major Functions of Lymphatic SystemFiltration of lymphReturn of seeped fluid to c.v. system“Education” and produc

4、tion of immune system lymphocytesTransport of digested lipids from small intestinal lacteals Lymph CapillariesThin walled endothelium (no BM) with periodic one way valves. In general they parallel veins.Closed ends allow fluid flow inward only Pick up and recycle extra tissue fluid Lymph circulation

5、 due to ?Compare to Fig. 23.2Location of Lymph CapillariesEverywhere, except for CNS and bone marrow, as well as cornea and cartilage.Special set of lymph capillaries in villi of small intestine = LactealsDamaged valves or blockedlymph vessels ?Lymphatic vesselscomparable in structure to veinsLymph

6、capillaries converge to become collecting vessels and end up as eitherThoracic duct or right lymphatic ductThoracic (left lymphatic) ductLeft subclavian veinRight lymphatic ductRight subclavian veinCysterna ChyliFig 23.4largestLymphocytesAgranulocytes - large nuclei and small amount of cytoplasm Fun

7、ction in identification and inactivation/destruction of pathogensTypes of Lymphocytes1. T Cells - cellular immunity - specific for previously identified pathogensT Helper, T Killer, T Suppressor, and memory cells2. B Cells - humoral immunity - plasma cells produce antibodies specific to the antigen

8、or pathogen; memory cells3. NK cells - non-specific, provide immunological surveillanceBone Marrow: LymphopoiesisLymphocytes are later also produced in thymus, spleen and tonsilsFig 23.7122 C.t. loaded with Lymphocytes Lymphoid nodules are unencapsulated clusters of lymphocytes ( 1mm). Found beneath

9、 epithelial lining of respiratory, digestive & urinary tracts Mucosa associated lymphatic tissue (MALT) in GI tract 5 tonsils aggregate lymphoid nodules in small intestine (= Peyers patches) appendix - walls contain lymphoid tissueLymphoid Tissue = adenoidsLymph Nodes 500 ( 1mm to 25 mm)Bean-sha

10、ped with hilusseveral afferent vessels, one efferent vessel Function?Popular term “lymph gland” is misnomer. Why?Contain lots of lymphocytes & MacrophagesClinical application: Swollen lymph nodesFig 23.9Distribution of LNsCervical lymph nodes - drain head and neckAxillary lymph nodes - drain arm

11、s and breastsPopliteal lymph nodes - drain legs, drain into Inguinal lymph nodes - drain lower limbThoracic lymph nodes - drain thoracic visceraAbdominal lymph nodes - drain pelvic regionIntestinal and mesenteric lymph nodes - drain abdominal visceraThymusLocation above heart, posterior to sternumDi

12、vided into lobulesOnly lymphoid organ that does NOT fight antigens, it functions as “T-cell academy” Blood thymus barrier prevents premature stimulation of developing T-cellsInvolution after pubertyEpithelial cells produce thymic hormonesLargest lymphoid organSoft and very blood richRed pulp sinusoi

13、ds containing RBCs lymphoid tissueMajor Functions:1. Initiation of Immune response to antigens in blood2. Removal of aged and defective RBCs3. Repository for new RBCs4. Fe salvaging, storage and recyclingSpleenFig 23-17Surfaces named for contacts: diaphragmatic, visceral, gastric, renalOverview of t

14、he Lymphatic SystemIncludes, vessels, fluid, and nodes or nonsecreting glands. Lymphatic vessels convey fluid from the periphery to the veins. The fluid, lymph (=clear spring water), is what seeps out of the blood at the peripheral capillaries. Composition is similar to plasma without the proteinsLy

15、mphatic organs or tissues (glands) are filtering areas and arenas of lymphocyte maturation and competency.Distribution of LNsCervical lymph nodes - drain head and neckAxillary lymph nodes - drain arms and breastsPopliteal lymph nodes - drain legs, drain into Inguinal lymph nodes - drain lower limbThoracic lymph nodes - drain thoracic visceraAbdominal lymph nodes - drain pelvic regionIntestinal and mesenteric lymph nodes - drain abdominal visceraThymusLocation above heart, posterior to s