Memmler’s A&P Chap 16 The lymphatic system

Lymphatic system p352 Functions: – Fluid balance – Absorption of fats: lacteals – Protection from infection

Lymphatic circulation p353 One way system of lymphatic vessels that begins in the tissues and ends when the lymph joins the blood. Lymphatic capillaries: More permeable than blood vessel capillary walls

Movement of lymph p355 Segments of lymphatic vessels located between the valves contract rhythmically, propelling the lymph forward. Movement of lymph is promoted by: – Valves – Skeletal muscles – Breathing

Lymphatic circulation p354 Superficial and deep lymphatic vessels 2 main lymphatic ducts Right lymphatic duct Thoracic duct Lymphatic ducts empty into the superior vena cava

Lymphoid tissue p355 Nodes Spleen Thymus Tonsils Other (appendix)

Lymph nodes p356 Filter lymph Sites where lymphocytes multiply

Spleen p357 Filters BLOOD to remove impurities and cellular debris Destroys worn-out RBCs Serves as a reservoir for blood

Thymus p358 The thymus is most active during early life. After puberty, the tissue undergoes changes. It shrinks in size and is replaced by connective tissue and fat.

Tonsils p358 3 areas of tonsils: Palatine tonsils Pharyngeal tonsils (adenoids) Lingual tonsils

Other lymphoid tissue p359 Appendix Peyer patches

Lacteals p353 Lacteals absorb fats that are too large to pass into the circulatory system Chyle More info on lacteals in Chap 19 page 420.

Disorders of the lymphatic system p Lymphedema Lymphadenopathy Lymphoma – Hodgkin disease – Non-Hodgkin lymphoma