The Lymphatic System and Lymphoid Tissue

1. The Lymphatic Systemand Lymphoid Tissue Anatomy & Physiology II Chapter 16

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

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

4. 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?

5. Lymphatic Circulation • One-way system • Begins in tissues • Ends in bloodstream

6. 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

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

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

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

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

11. 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

12. 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?

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

14. 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

15. 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

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

17. 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

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

19. 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

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

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

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

23. End of Presentation