Lymphatic System

Lymphatic System Functions Fluid & Protein Balance Return excess interstitial fluid and leaked proteins to blood Digestion Lacteals transport dietary lipids (chyle) Vitamins A, D, E and K from GI tract Immune Response Cell mediated immune responses—T cells destroy intruders with cytotoxic substances. Antibody-mediated immune responses detect and destroy specific foreign substances. 2

Lymphatic System Components Fluid of the lymphatic system Similar to blood plasma and interstitial fluid Lymphatic Vessels Transport lymph Lymph is returned to the circulatory system at either the right or left subclavian veins Lymphoid tissues House phagocytic and lymphoid cells 3

Lymphatic Vessels Lymphatic capillaries resemble veins but have thinner walls and more valves. Lymph vessels in the skin follow veins. Lymph vessels in the viscera follow arteries. Lymph vessels are NOT found in avascular tissue, CNS, parts of spleen and red bone marrow. 4

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Flow of Lymph Blood capillaries (blood)  interstitial spaces  lymph capillaries  lymph vessels  lymph trunks  thoracic and right lymphatic duct  junction of the internal and subclavian veins (blood). Smooth muscles in lymph vessels contract rhythmically Pulsations in adjacent arteries aid flow Skeletal muscle and respiratory pump 6

Lymphatics & the Breast Flow of Lymph Lymphatics & the Breast 7

Lymphoid Cells Lymphocytes Macrophages Dendritic cells Reticular cells T-cells B-cells Macrophages Dendritic cells Reticular cells 8

Lymphoid Tissue Site for lymphocyte residence and proliferation Provides sentinel position for lymphocytes and macrophages Lymphocytes cycle among lymphoid tissue, blood circulation and loose connective tissue. Can be diffuse or densely organized 9

Lymph Nodes 2 Functions: Filter lymph Activate immune system Microorganisms Cancer cells 10

Lymph nodes 2 Regions: Cortex Medulla B cells T cells Lymph Sinuses & macrophages Lymph Nodes Animation 11

Lymphoid Organs Lymph Nodes Spleen Thymus Tonsils Peyer’s patches MALT 12

Spleen White pulp Red pulp Erythrocyte production in fetus B and T cells carry out immune function. Red pulp Removes aged and defective RBCs Stores breakdown products of RBCs Erythrocyte production in fetus Stores blood platelets Has regenerative properties 13

Thymus Secretes thymopoietin, thmosins to make T-cells immunocompetent Bilobed organ Trabeculae divide lobe into lobules. Thymic corpuscles 14

Tonsils & Adenoids Trap bacteria which work their way into the follicles where they are destroyed This helps develop memory 15

Appendix Possibly works with the Peyer's patches to help defend against invaders from the digestive system

MALT Mucosa-associated lymphatic tissue 17

Causes of Edema Edema Accumulation of interstitial fluid Blockage of lymphatic system Increased pressure in veins Lack of albumin Decreases fluid returning to blood capillaries by osmosis Inflammation 18

Homeoimbalances of the Lymphatic System Autoimmune Lymphoproliferative Syndrome (ALPS) Lymphatic Filariasis Mesenteric Lymphadenitis Swollen Lymph Nodes Castleman Disease Adenoids Splenomegaly Hodgkin's disease Kawasaki disease

Nonspecific Body Defenses Phagocytosis Complement Fever Inflammation Skin Acid Stomach Vagina Mucus Saliva Tears 20

Complement 21

Inflammation Bodies response to tissue injury Classic signs Heat Redness Swelling Pain 22