Presentation on theme: "Chap 19 – Lymphatic System"— Presentation transcript:
1Chap 19 – Lymphatic System Homework: Read Chap 19. Review anatomical structures & physiology (per diagrams).Learning Objectives:1.List the functions of the lymphatic system.2. Describe the source of lymph & its transport.4. Describe lymph tissue.5. Describe lymph nodes (locations structure and distribution of the lymph vessels.3. Explain the, histology, function, etc.)6. Name and describe other lymphoid organs of the body.
2What’s the Problem?These patients have an imbalance called ___________.
3Opening DiscussionWhat does the lymphatic system do? How does it tie-in to what we have been studying?
4Circulatory DilemmaProblem: Capillaries are known to be ‘leaky’ vessels. They leak about 3L of interstitial fluid into tissue spaces daily.All this fluid must be returned to the cardiovascular system to ensure sufficient blood volumeHow does it get returned?
5Lymphatic System To The Rescue! The lymphatic system - an elaborate system of drainage vessels that collect excess interstitial fluid and return it to the bloodstream
6How Does It Work? Instructions: 1. Take time to reflect. 2. Review Figure 19.1 (page 680) and the associated text, “Distribution and Structure of Lymphatic Vessels”.3. Write a 1-3 sentence summary in your own words of how it basically works. Place the summary in your notes next to this slide.4. Be prepared to share with class.Estimated Time: 3-5 minutes
7Lymph VesselsA __________ system in which lymph flows toward the heartLymph vessels include:Microscopic, permeable, blind-ended capillariesLymphatic collecting vesselsTrunks and ducts
8Lymph Collecting Vessels Have the same three ______ as veinsHave _______ walls, with more internal valvesCollecting vessels in the skin travel with superficial veinsDeep vessels travel with arteries
9Lymph Capillaries Similar to blood _________, with modifications Remarkably ___________Loosely joined endothelial minivalves (withstand interstitial pressure and remain open). Also, function as one-way gates that:a) Allow interstitial fluid to enter lymph capillariesb) Do not allow lymph to escape from the capillaries
10Lymph Capillaries continued During inflammation, lymph capillaries can absorb:_____ debris________________ cellsCells in the lymph nodes:Cleanse and __________ this debrisLacteals – specialized lymph capillaries present in intestinal mucosaAbsorb digested fat and deliver chyle (fatty lymph) to the blood
11Lymph TransportThe lymphatic system _______ an organ that acts as a pumpVessels are ____-pressure conduitsUses the same methods as _____ to propel lymphPulsations of nearby arteriesContractions of smooth muscle in the walls of the lymphatics
12General Distribution of Vessels and Regional Lymph Nodes Label your practice diagram.Page 682
13Lymphatic TrunksLymphatic trunks are formed by the union of the largest collecting ___________Major trunks include:Paired ________, bronchomediastinal, subclavian, and ________ trunksA single intestinal trunkLymph is delivered into one of two large ___________ lymphatic duct – drains the right upper arm and the right side of the head and thorax_______ duct – arises from the cisterna chyli and drains the rest of the body
14Lymphatic TrunksLabel your practice diagramPage 682
15Lymphoid Cells____________ are the main cells involved in the immune response . The two main varieties are _ cells and _ cells (protect the body against foreign antigens such as bacteria, viruses, & cancer)__________ – phagocytize foreign substances and help activate T cells________ cells – spiny-looking cells with functions similar to macrophages________ cells – fibroblastlike cells that produce a stroma, or network, that supports other cell types in lymphoid organs
16Lymph NodesLymph nodes are the principal lymphoid ________ of the bodyNodes are imbedded in _______ tissue and clustered along lymphatic vesselsAggregations of these nodes occur near the body surface in inguinal, _______, and cervical regions of the body
17Functions of Lymph Nodes Their two basic functions are:____________ – macrophages destroy microorganisms and debris________ ______ __________ – monitor for antigens and mount an attack against them
18Lymph Node Structure________ are bean shaped and surrounded by a fibrous capsuleNodes are ______________ (trabeculae extend inward)Nodes have two histologically distinct regions: a _______ and a _______
19Lymph Node Structure continued Label your practice diagram.
20Lymph Node Structure continued The cortex contains _________ with germinal centers, heavy with dividing B cells__ _______ circulate continuously among the blood, lymph nodes, and lymphatic stream_________ cords extend from the cortex and contain B cells, T cells, and plasma cellsThroughout the node are lymph _______ crisscrossed by reticular fibers. Macrophages reside on these fibers and phagocytize ______ matter
21Other Lymphoid Organs The ____, ______ gland, and _______ _________ patches and bits of lymphatic tissue scattered in connective tissueAll are composed of reticular connective tissue and all help protect the bodyOnly lymph nodes filter lymph
22Spleen_________ lymphoid organ, located on the left side of the abdominal cavity beneath the diaphragmFunctionsSite of lymphocyte proliferationImmune surveillance and responseCleanses the ______Stores blood ________
23Spleen Structure, page 686 Two distinct areas of the spleen are: _____ pulp – area containing mostly lymphocytes suspended on reticular fibers and involved in immune functions_____ pulp – remaining splenic tissue concerned with disposing of worn-out RBCs and bloodborne pathogens
24ThymusA bi-lobed organ that secrets hormones (thymosin and thymopoietin) that cause T lymphocytes to become immunocompetentThe size of the thymus varies with ageIt increases in size and is most active during ________It stops growing during adolescence and then gradually _________
25Thymus continuedThe thymus _______ from other lymphoid organs in important waysIt functions strictly in T lymphocyte ________It does not directly fight _______The thymus consists of star-shaped epithelial cells (not reticular fibers)
26TonsilsSimplest lymphoid organs; form a ring of lymphatic tissue around the _______Like little crypts - ____ and ______ bacteria and particulate matter
27Other continuedPeyer’s patches – isolated clusters of lymphoid tissue, similar to tonsilsFound in the wall of the distal portion of the _____ _________Similar structures are found in the appendix_____ – mucosa-associated lymphatic tissue (protects the digestive and respiratory systems from foreign matter)