Chapter 16: The Lymphatic System and Lymphoid Tissue

Overview

Key Terms adenoid lymphadenopathy lymphoma chyle lymphangitis spleen lymph lymphatic duct thymus lymphadenitis lymph node tonsil

The Lymphatic System System of tissues and vessels Scattered throughout the body Services almost all regions

Functions of the Lymphatic System Learning Outcome List the functions of the lymphatic system.

Functions of the Lymphatic System Three Main Functions Fluid balance (lymph) Protection from infection Absorption of fats

Functions of the Lymphatic System ✓ Functions of the Lymphatic System Checkpoint 16-1 What are the three functions of the lymphatic system? 7

Lymphatic Circulation Learning Outcomes Explain how lymphatic capillaries differ from blood capillaries. Name the two main lymphatic ducts and describe the area drained by each.

Lymphatic Circulation One-way system Begins in tissues Ends in bloodstream

Figure 16-1 The lymphatic system in relation to the cardiovascular system. What type of blood vessel receives lymph collected from the body?

Lymphatic Circulation Lymphatic Capillaries Capillary walls (endothelium) are flattened epithelial cells. They are more permeable than blood capillaries. Overlapping cells form one-way valves. They arise blindly (closed at one end). Lacteals absorb digested fats.

Figure 16-2 Lymphatic drainage in the tissues. 12

Lymphatic Circulation Lymphatic Vessels Superficial and deep sets Right lymphatic duct Thoracic duct (left lymphatic duct) Cisterna chyli

Figure 16-3 Vessels and nodes of the lymphatic system. What are some nodes that receive lymph drainage from the breast? 14

Lymphatic Circulation Movement of Lymph Movement of lymph toward heart caused by: Valves in lymphatic vessels Contraction of lymphatic vessels Skeletal muscle contraction Breathing

16

Lymphatic Circulation ✓ Lymphatic Circulation Checkpoints 16-2 What are the two differences between blood capillaries and lymphatic capillaries? 16-3 What are the two main lymphatic vessels? 17

Lymphatic Circulation ? Lymphatic Circulation Pop Quiz 16.1 Which of the following is NOT characteristic of lymphatic vessels? A) They have thin walls. B) They are blind-ended. C) They can contract to propel lymph. D) They transport lymph to the tissues.

Lymphatic Circulation ? Lymphatic Circulation Pop Quiz Answer 16.1 Which of the following is NOT characteristic of lymphatic vessels? A) They have thin walls. B) They are blind-ended. C) They can contract to propel lymph. D) They transport lymph to the tissues.

Lymphoid Tissue Learning Outcome List the major structures of the lymphatic system and give the locations and functions of each.

Lymphoid Tissue Distributed throughout the body Makes up specialized organs of lymphatic system

Figure 16-5 Location of lymphoid tissue. 22

Lymphoid Tissue Lymph Nodes Cervical nodes Axillary nodes Tracheobronchial Mesenteric nodes Inguinal nodes

Figure 16-3 Vessels and nodes of the lymphatic system. What are some nodes that receive lymph drainage from the breast? 24

Figure 16-4 Lymph nodes. What type of lymphatic vessel carries lymph into a node? What type of lymphatic vessel carries lymph out of a node? 25

Lymphoid Tissue The Spleen Cleanses blood Filtration Phagocytosis Destroys old red blood cells Produces red blood cells before birth Is a reservoir for blood

Lymphoid Tissue The Thymus Plays a key role in early immune system development Produces thymosin Develops T-lymphocyte cells Promotes lymphocyte growth Promotes lymphoid tissue activity Shrinks after puberty

Lymphoid Tissue The Tonsils Remove contaminants and trap pathogens Palatine tonsils Pharyngeal tonsil (adenoids) Lingual tonsils Surgery to treat if recurrent infection or enlarged tonsils make swallowing or breathing difficult

Figure 16-6 Location of the tonsils. 29

Lymphoid Tissue Other Lymphoid Tissue Appendix Mucosal-associated lymphoid tissue (MALT) Gut-associated lymphoid tissue (GALT)

31

✓ Lymphoid Tissue Checkpoints 16-4 What is the function of the lymph nodes? 16-5 What is filtered by the spleen? 16-6 What kind of immune system cells develop in the thymus? 16-7 What is the general location of the tonsils? 32

? Lymphoid Tissue Pop Quiz 16.2 Lymph from the arm and breast passes through which of the following? A) Inguinal nodes B) Cervical nodes C) Axillary nodes D) Tracheobronchial nodes

? Lymphoid Tissue Pop Quiz Answer 16.2 Lymph from the arm and breast passes through which of the following? A) Inguinal nodes B) Cervical nodes C) Axillary nodes D) Tracheobronchial nodes

Disorders of the Lymphatic System Learning Outcome Describe the major lymphatic system disorders.

Disorders of the Lymphatic System and Lymphoid Tissue Disorders Related to Infection Lymphadenopathy Lymphadenitis Infectious mononucleosis Lymphedema Elephantiasis

Figure 16-7 Infectious mononucleosis. 37

Figure 16-8 Lymphangitis. 38

39

Disorders of the Lymphatic System and Lymphoid Tissue Splenomegaly Lymphoma Hodgkin lymphoma Non-Hodgkin lymphoma

Figure 16-9 Reed-Sternberg cell. 41

Disorders of the Lymphatic System and Lymphoid Tissue ✓ Disorders of the Lymphatic System and Lymphoid Tissue Checkpoints 16-8 What is lymphadenopathy? 16-9 What is lymphoma and what are the two examples of malignant lymphoma? 42

Disorders of the Lymphatic System and Lymphoid Tissue ? Disorders of the Lymphatic System and Lymphoid Tissue Pop Quiz 16.3 What is Hodgkin lymphoma? A) A benign tumor of the lymph nodes B) A malignant tumor of the lymph nodes C) A benign tumor of the spleen D) A malignant tumor of the spleen

Disorders of the Lymphatic System and Lymphoid Tissue ? Disorders of the Lymphatic System and Lymphoid Tissue Pop Quiz Answer 16.3 What is Hodgkin lymphoma? A) A benign tumor of the lymph nodes B) A malignant tumor of the lymph nodes C) A benign tumor of the spleen D) A malignant tumor of the spleen

Case Study Learning Outcome 6. Describe the spleen’s functions and the consequences of its removal.   45

Case Study Functions of the Spleen Filters blood Removes worn-out old blood cells Acts as a large lymph node, detecting and fighting disease-causing organisms Consequences of Splenectomy Liver will take over blood filtration and RBC removal Greater risk of infection

Word Anatomy Learning Outcome Show how word parts are used to build words related to the lymphatic system. 47

Word Anatomy Word Part Meaning Example -oid like, resembling Lymphoid tissue makes up the specialized organs of the lymphatic system. aden/o gland The adenoids are gland-like tonsils. lingu/o tongue The lingual tonsils are at the back of the tongue. -pathy any disease Lymphadenopathy is any disease of the lymph nodes. -megaly excessive enlargement Splenomegaly is excessive enlargement of the spleen.

49