Functions of Lymphatic systems

move excess tissue fluid back to veins; lipid transport; filter fluid bacteria/viruses

Inerstitial fluid

fluid in capillaries that squeezed out by blood pressure

edema

fluid is not removed and body tissue swells

lacteals

specialized lymph vessels where the fat is absorbed because fat molecules are too large for capillaries

structure of Lymphatic system

lymphatic capillaries are wider; larger lymphatic collecting vessels are similar to veins; larger lymphatic ducts empty into sublcavian veins

2 major lymphatic ducts

thoracic and right lymphatic duct

Thoracic Duct

largest lymphatic vessel w/ a length of 15-18 inches

Right lymphatic duct

located near the right clavicle and returns lymph to the junction of the right sublcavian and right internal jugular vein

Immune system

widespread system that attacks foreign invaders

Non specific defense of Immune system

skin; acidity; fever; phagocytosis

Specific defense

cells recognize and attack specific invaders; receptor proteins on surface of cell; antigens on invader; cells = lymphocytes; widespread but concentrated on lymphoid organs

B cells

fight bacteria/viruses

T cells

fight infected cells, cancer cells

vaccines

memory cells after invader is eliminated; formed by lymphocytes

Organs of the Immune system

lymphoid tissue; lymph nodes; appendix & peyer's patches; tonsils; spleen; thymus

Lymphoid tissue

reticular connective tissue w/ clusters of lymphocytes

Lymph nodes

lymph (fluid) drains through node; immune system cells destroy pathogens

Appendix & Peyer's patches

areas of lymphoid tissue in intestine

Tonsils

4 pairs around entrance to pharynx: pharyngeal, lingual, palatine, tubal

Spleen

reticular tissue; posterior left of stomach; filters blood/destroys RBC; contains lymphoid tissue

Thymus

located above the heart; degenerates in adults; site of lymphocyte development