Chapter 20: Lymphatic System Chapter 20: Lymphatic System

TheHuman Bodyin Healthand Illness

Barbara Herlihy

Chapter 20:Lymphatic System

Chapter 20:Lymphatic System

Copyright © 2007 by Saunders, an imprint of Elsevier Inc.All rights reserved.

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LymphLymph

• Lymph: clear fluid that resembles plasma and is formed from plasma during capillary exchange

• Composition of lymph: water, electrolytes (Na+ and Cl-), waste from metabolizing cells, and some Albumin (protein) that leaks out of the capillaries of the systemic circulation

• Lymph: clear fluid that resembles plasma and is formed from plasma during capillary exchange

• Composition of lymph: water, electrolytes (Na+ and Cl-), waste from metabolizing cells, and some Albumin (protein) that leaks out of the capillaries of the systemic circulation


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Lymph (cont’d.)Lymph (cont’d.)

• Formation: water and dissolved solute filters out of capillaries and into tissues tissue fluid drains into lymphatic vessels drains into larger ducts and then into blood

• 20 L/24 hours is formed

• Formation: water and dissolved solute filters out of capillaries and into tissues tissue fluid drains into lymphatic vessels drains into larger ducts and then into blood

• 20 L/24 hours is formed


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Lymphatic VesselsLymphatic Vessels

Lymph capillaries and blood capillaries.Lymph capillaries and blood capillaries.


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Lymphatic Vesselks (cont’d.)Lymphatic Vesselks (cont’d.)

• Lymphatic vessels: includes lymphatic capillaries and several larger lymphatic vessels; “run with” the veins

• Veins similar to blood vessels, including valves

• Lymphatic vessels: includes lymphatic capillaries and several larger lymphatic vessels; “run with” the veins

• Veins similar to blood vessels, including valves


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Lymphatic Vessels (cont’d.)Lymphatic Vessels (cont’d.)


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• Drainage of lymph: • Most lymph drains into the thoracic duct• Lymph from the right arm, right side of head, and thorax drain into right lymphatic duct•Both ducts empty into the subclavian veins


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• Forces that move lymph: • Not pumped like blood• Moves in response to:

• skeletal muscle contraction• chest movement• contraction of smooth muscle in the lymphatic vessels


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Elephantiasis


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lymphedema


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Lymphoid OrgansLymphoid Organs

• Organs:– Lymph nodes– Tonsils – Thymus gland– Spleen

• Functions:– Filter particles from lymph, tissue fluid, and

blood– Support immune activities of lymphocytes– Protect body against infection

• Organs:– Lymph nodes– Tonsils – Thymus gland– Spleen

• Functions:– Filter particles from lymph, tissue fluid, and

blood– Support immune activities of lymphocytes– Protect body against infection


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Lymphoid Organs (cont’d.)Lymphoid Organs (cont’d.)


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• Lymph nodes: small pea-shaped patches of lymphatic tissue that filter lymph as it flows through the lymphatic system– Cervical lymph nodes drain and cleanse lymph

from head and neck areas– Axillary lymph nodes drain and cleanse lymph

from upper extremities, shoulders, and breast area

– Inguinal lymph nodes drain and cleanse lymphfrom lower extremities and external genitalia

• Lymph nodes: small pea-shaped patches of lymphatic tissue that filter lymph as it flows through the lymphatic system– Cervical lymph nodes drain and cleanse lymph

from head and neck areas– Axillary lymph nodes drain and cleanse lymph

from upper extremities, shoulders, and breast area

– Inguinal lymph nodes drain and cleanse lymphfrom lower extremities and external genitalia


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Lymphoma


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• Tonsils: partially encapsulated lymph nodes in the throat area

• Locations:– Palatine tonsils: opening of oral cavity into

pharynx– Pharyngeal tonsils: opening of nasal cavity in

upper pharynx (also called “adenoids”)– Lingual tonsils: back of the tongue

• Tonsils: partially encapsulated lymph nodes in the throat area

• Locations:– Palatine tonsils: opening of oral cavity into

pharynx– Pharyngeal tonsils: opening of nasal cavity in

upper pharynx (also called “adenoids”)– Lingual tonsils: back of the tongue


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TonsilsTonsils


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TonsillitisTonsillitis


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TonsillectomyTonsillectomy

Postoperative bleeding is a concern


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• Thymus gland: produces and helps differentiate the lymphocytes (T cells), located in the upper mediastinum thoracic cavity, shrivels up after puberty

• Plays an important role in the immune response

• Thymus gland: produces and helps differentiate the lymphocytes (T cells), located in the upper mediastinum thoracic cavity, shrivels up after puberty

• Plays an important role in the immune response


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• Spleen: largest lymphoid organ in the body; located in the upper left quadrant of the abdominal cavity just beneath the diaphragm

• Very vascular• Considered a large lymph node

• Spleen: largest lymphoid organ in the body; located in the upper left quadrant of the abdominal cavity just beneath the diaphragm

• Very vascular• Considered a large lymph node


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• Functions of the spleen:– Filters blood– Stores blood– Has resident WBCs that phagocytose

microorganisms– Removes worn-out red blood cells and platelets– Produces RBCs before birth

• When injured, presents a major bleeding problem spleenectomy may be needed

• Functions of the spleen:– Filters blood– Stores blood– Has resident WBCs that phagocytose

microorganisms– Removes worn-out red blood cells and platelets– Produces RBCs before birth

• When injured, presents a major bleeding problem spleenectomy may be needed

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Chapter 20: Lymphatic System Chapter 20: Lymphatic System