Lymphatic System A&P Chapter 15 Pg 461

Introduction Consists of : lymph, lymph vessels, lymph nodes, and lymph tissue

Lymph Thin watery fluid Made of interstitial, or intercellular fluid that forms when plasma diffuses into tissue spaces. Composed of water, digested nutrients, salts, hormones, CO2, lymphocytes, and metabolic waste

Lymphatic Vessels Located throughout the body Lymphatic capillaries: small saclike open-ended vessels; acts like drainpipes; picks up lymph at tissues throughout the body; capillaries joint together to form larger lymphatic vessels Lymphatic vessels carry lymph Skeletal muscle contraction causes lymph flow

Lymphatic Vessels cont’ Vessels pass through lymph nodes Contain valves that keep lymph flowing in one direction Specialized lymphatic capillaries (lacteals) are located in the small intestine –Pick up digested fats or lipids –Lymph is mixed with lipids = chyle –Lacteals transport chyle to the bloodstream

Lymph Nodes Popularly called “glands” Located all over the body, usually in small clusters Small round masses ranging in size from a pinhead to an almond Lymph vessels bring lymph to the nodes

Lymph Nodes Nodes filter out impurities such as: –Carbon –Cancer cells –Pathogens –Dead blood cells Lymphatic tissue in nodes also produce lymphocytes: (a type of leukocyte= WBC), and antibodies (substances that fight infection)

Lymph Nodes Purified lymph, with lymphocytes and antibodies added leaves the lymph node by a single lymphatic vessel

Lymphatic Ducts As lymphatic vessels leave the lymph nodes, they continue to join together to form larger lymph vessels Eventually they drain into one of two lymphatic ducts: Right or the Thoracic

Lymphatic Ducts Right Duct: –Short tube –Receives all the purified lymph form the right side of the neck and head, the right chest, and the right arm

Lymphatic Ducts Thoracic Duct: Much larger tube Drains lymph from the rest of the body Empties into the R Subclavian Vein, returning purified lymph to the blood

Lymphatic Ducts Thoracic Duct cont’ Enlarged pouchlike structure called the cisterna chyli is located at the start of the thoracic duct and serves as storage area for purified lymph

Lymph Tissue Located throughout the body in addition to being in lymph nodes Tonsils, spleen, and thymus are examples of lymphatic tissue Tonsils: Masses of lymph tissue; filter interstitial fluid; 3 pairs of tonsils= palantine, pharngeal (adenoids), and lingual

Lymph Tissue Spleen Organ located on L side in back of the upper part of the stomach Produces leukocytes and antibodies Destroys old RBC’s; Stores RBC’s Destroys thrombocytes, Filters some metabolites and wastes from tissue

Lymph Tissue Thymus Mass of lymph tissue located in the center of the upper chest Atrophies or wastes away after puberty and is replaced by fat and connective tissue

Lymph Tissue Functions during early life by producing antibodies and manufacturing lymphocytes to fight infection Function is taken over by lymph nodes after it atrophies