The Human Body in Health and Illness, 4 th edition Barbara Herlihy Chapter 20: Lymphatic System 1

The Human Body in Health and Illness, 4th edition

Barbara Herlihy

Chapter 20:Lymphatic System

1

Lesson 20-1 Objectives

• List three functions of the lymphatic system.• Describe the composition and flow of lymph.• State the location of the following lymph

nodes: cervical nodes, axillary nodes, and inguinal nodes.

• Describe the four lymphoid organs: lymph nodes, tonsils, thymus gland, and spleen.

Copyright © 2011, 2007 by Saunders, an imprint of Elsevier Inc. All rights

reserved.2

The Lymphatic System: Functions

• Returns interstitial fluid to the blood

• Absorbs fats and fat-soluble vitamins

• Helps the body defend itself against infection


reserved.3

Lymphatic Vessels and Veins• Veins and lymphatic vessels drain interstitial fluid.


reserved.4

Formation of Lymph

Blood interstitial fluid lymph


reserved.5

Lymph Nodes and Lymph Vessels

• Lymphatic vessels travel with veins, help with drainage

• Lymph travels through vessels to nodes

• Nodes: Sites of phagocytosis and immune response


reserved.6

What Makes Lymph Move?

• Milking action of skeletal muscles– Exercise is good.

• Movement of chest during respiration– Creates variations in pressure.

• Rhythmic contractions of lymphatic smooth muscle– Vessel walls contract to push lymph along.


reserved.7

Lymphatic Drainage: Main Ducts

• Two drainage areas: Right lymphatic duct and thoracic duct

• Both ducts drain into subclavian veins.


reserved.8

Lymphoid Organs

• Lymph nodes• Tonsils • Thymus gland• Spleen• MALT (mucosal-associated lymphoid tissue)


reserved.9

Lymph Node: Two Compartments

• Lymph nodules– Lymphocytes and

macrophages– Immunity,

phagocytosis

• Lymph sinuses– Are lymph-filled

spaces– Bathe lymph nodules


reserved.10

Lymphatic System: Diffuse

• Lymphatic vessels drain most of the body.

• Nodes are grouped.– Cervical– Axillary– Inguinal


reserved.11

Lymphoid Organs: Tonsils

• Pharyngeal tonsils or adenoids

• Palatine tonsils often target of tonsillectomy

• Lingual tonsils


reserved.12

Lymphoid Organ: Thymus Gland

• Assists development of immune system before puberty

• Secretes thymosins • Produces T cells

(lymphocytes)


reserved.13

Lymphoid Organ: Spleen• Red pulp: Venous

sinuses filled with blood and phagocytes

• White pulp: Contains lymphocytes

• Stores RBCs and platelets

• Removes old RBCs and platelets


reserved.14

Documents

The Human Body in Health and Illness, 4 th edition Barbara Herlihy Chapter 20: Lymphatic System 1