Chapter 21 Study Guide Lymphatic System 1 What are the main functions of the Lymphatic system 1 1 Fluid recovery fluid continuously filters from the blood capillaries into the tissue spaces 2 2 Immunity excess filtered fluid picks up foreign cells and chemicals from the tissues 3 3 Lipid Absorption lacteals in small intestine absorb dietary lipids that are not absorbed by the blood capillaries 2 Components of the Lymphatic System 1 1 Lymph fluid similar to blood plasma but LOW in protein content 2 2 Lymphatic vessels 3 3 Lymphoid tissues and organs 3 What is the primary function of lymphatic vessels related to interstitial fluid and capillary beds Fluid is forced out of blood at the arterial end of capillary bed and are reabsorbed at the venous end The leaked fluid interstitial fluid has to be returned to blood to maintain proper blood volume Lymphatic vessels collect interstitial fluid 4 Which circulatory vessels are lymphatic capillaries closely associated with Why do you think this is the case Lymphatic capillaries are associated with capillary beds and loose connective tissue of the body 5 In which direction does lymph flow Lymph flows in one direction towards the heart 6 How do the minivalves of lymphatic capillaries work Endothelial cells overlap forming minivalves Increases in interstitial fluid volume causes minivalves to open fluid enters Decreases in interstitial fluid volume close minivalves prevents backflow 7 How are lymphatic collecting vessels similar to veins Lymphatic vessels for in the embryp by budding from the veins so they have similar histology tunica interna endothelium and valves mediaelastic fibers and smooth muscle and externa thin Their walls are thinner and their valves are closer together than those of veins 8 Can you outline the sequence of structures through which lymph flows from lymphatic capillaries to the heart Lymphatic capillaries lymphatic collecting vessels internal valves prevent backflow lymph nodes fluid detox destruction of bacteria viruses cancer cells Lymphatic trunks where collecting vessels unite Lymphatic ducts right lymphatic duct which goes to the right upper arm and the ride side of head and thorax thoracic duct goes to the rest of the body 9 What are the main two lymphatic ducts and which areas of the body do they service Right lymphatic duct which goes to the right upper arm and the ride side of head and thorax Thoracic duct goes to the rest of the body 10 What is the cisterna chyli Gateway to the thoracic duct Merger of two lumbar trunks intestinal trunk 11 Which mechanisms facilitate the transport of lymph from body tissues to the heart Which of these are similar to the mechanisms used by veins Flow of lymph relies on o Skeletal muscle milking o Respiratory pumps changes in pressure of thoracic cavitybreathing o Valves to prevent backflow o Close association with arteries arterial pulses promote lymph transport o Smooth muscle in lymphatic trunks and thoracic duct o Activity level speed transport Very similar to venous return of blood to the heart except the lymphatic system has no pump like the heart and lymph flows at even lower pressure and speed than venous blood 12 Which types of cells 4 main types reside in the lymphoid tissue What are the functions of these cells Lymphocytes arise in the red bone marrow natural killer NK cells destroy bacteria and infected host cells mature into T lymphocytes which direct attack on infected cells or invaders mature into B lymphocytes which produce plasma cells that secrete antibodies against foreign substances antigens Macrophages phagocytize foreign substances and activate T lymphocytes Dendrite Cells capture antigens transport to lymph nodes activate T lymphocytes Reticular Cells produce stroma fibrous network that supports other lymphoid cells 13 What is the primary function of lymphoid tissue Lymphatic tissue is critical for proper functioning of the immune system o It is the site proliferation of lymphocytes o Fibrous network provides good surveillance points for immune cells lymphocytes 14 What is the difference between diffuse lymphatic tissue and lymphoid follicles Lymphatic follicles nodules concentrations of lymphoid tissue that form larger lymphoid organs like lymph nodes 15 What is the germinal center within a lymphoid follicle Germinal centers provide proliferation grounds for dendritic cells and B lymphocytes 16 What are lymph nodes What are their primary functions Where are they located rest stops for lymph where fluid filtration occurs secondary organs of the lymphatic system they are clustered around lymphatic vessels and embedded in connective tissue of the body Functions o 1 Filtration of microorganisms and debris from loose connective tissue by macrophages prevents delivery to blood and other body parts o 2 Immune system activation when antigens are detected by resident lymphocytes attack is initiated 17 Which layer is the cortex inside or outside The medulla Cortex outer layer of the lymph node Medulla inner layer of the lymph node 18 Which structures compose the cortex of a lymph node And which types of cells would you find there The cortex contains densely packed follicles with germinal centers Germinal centers house proliferating B cells dendritic cells and active T cells surveillance 19 Which structures compose the medulla of a lymph node And which types of cells would you find in the medulla that are not found in the cortex Medullary cords are thin inward extensions from the cortex contain B and T lymphocytes PLASMA CELLS 20 Where do macrophages reside within the lymph node medulla 1 In the medullary cords 21 Can you track the flow of lymph within a lymph node Lymph enters the lymph node through the afferent lymphatic vessels subcapsular sinus medullary sinus hilum efferent lymphatic vessels filtered lymph exits lymph node 22 What is the advantage of having fewer efferent than afferent vessels 23 What are buboes How does this relate to the Bubonic Plague Buboes swollen lymph nodes cause by tremendous s of bacteria trapped in a lymph node immune system can t keep up and inflammation The Bubonic Plague was the in the 1300 s in Europe 1900 s in India and USA it was known as the BLACK DEATH Plague causes fever and a painful swelling of the lymph glands called buboes which is how it gets its name The disease also causes spots on the skin that are red at first and then turn black 24 What are the major lymphoid organs Do any of these filter lymph like the lymph