The Lymphatic System and Lymphoid Tissue 4/16/2017 7:33 AM The Lymphatic System and Lymphoid Tissue Anatomy & Physiology II Chapter 16 © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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

Functions of the Lymphatic System Fluid balance Lymph fluid Protection from infection Absorption of fats

lymphatic system in relation to the cardiovascular system Lymphatic vessels pick up fluid in the tissues and return it to the blood in vessels near the heart. Zooming In: What type of blood vessel receives lymph collected from the body?

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

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

Lymphatic Vessels Superficial sets Deep sets Nodes Right lymphatic duct Thoracic duct (left lymphatic duct) Cisterna chyli

Lymph Vessels and Lymph Nodes Lymph nodes and vessels of the head. Drainage of right lymphatic duct and thoracic duct into subclavian veins.

Movement of Lymph Segments of vessels located between the valves contract rhythmically Skeletal muscles compress vessels

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

Lymph Nodes Structure Fibrous connective tissue capsule Afferent lymphatic vessel Hilum Sinuses Cords Nodules Medulla Efferent lymphatic vessel Grouping Cervical nodes Axillary nodes Mesenteric nodes Inguinal nodes

Structure of a lymph node Arrows indicate the flow of lymph through the node. Section of a lymph node as seen under the microscope (low power). Zooming In: What type of lymphatic vessel carries lymph into a node? What type of lymphatic vessel carries lymph out of a node?

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

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

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/breathing difficult

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

The Reticuloendothelial System Cells responsible for destroying worn-out blood cells, bacteria, cancer cells and other harmful foreign substances Monocytes Macrophages Kupffer cells Dust cells

Disorders of the Lymphatic System and Lymphoid Tissue Lymphangitis Septicemia Lymphadenitis Cervical Chronic

Lymphedema Tissue swelling due to obstruction of lymph flow caused by Infection of lymphatic vessels Vessel blockage Malignant growth Parasites Loss of lymphatic vessels from injury or surgery

Lymphadenopathy Enlarged lymph nodes accompany certain diseases and infections Acquired immunodeficiency syndrome (AIDS) Infectious mononucleosis

Splenomegaly Enlarged spleen accompanies certain diseases and infections Scarlet fever Typhus fever Typhoid fever Syphilis Tropical parasitic diseases Splenic anemia

Lymphoma Any tumor in lymphoid tissue Malignant disease Hodgkin disease Non-Hodgkin lymphoma

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