1. Memmler’s The Human Body in Health and Disease 11th edition
Chapter 16
The Lymphatic System and Lymphoid Tissue

2. The Lymphatic System System of tissues and vessels
Scattered throughout the body
Services almost all regions
Only CNS, bone and cartilage, and epithelium do NOT have contact

3. Functions of the Lymphatic System
Fluid balance (picks up excess fluid and protein)
Lymph fluid
Protection from infection (lymphocytes live and multiply here)
Absorption of fats (ones too large to enter capillaries)

4. The lymphatic system in relation to the cardiovascular system
The 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.  

5. Lymphatic Circulation
One-way system (not a complete circuit)
Begins in tissues
Ends in bloodstream

6. Lymphatic Capillaries
Capillary walls (endothelium) are flattened epithelial cells
Travels and follows capillaries
More permeable than blood capillaries
Overlapping cells form one-way valves
Arise blindly (closed at one end)
Lacteals (found in small intestine) absorb digested fats

7. Lymphatic Vessels Superficial sets Deep sets Nodes
Right lymphatic duct (bodies superior right quadrant)
Thoracic duct (all other body parts)
Cisterna chyli – enlarged part to store chyle
Chyle – milky fluid that drains from intestinal lacteals
Look on pg. 353
for structure

8. Vessels and nodes of the lymphatic system
Vessels and nodes of the lymphatic system. (A) Lymph nodes and vessels of the head. (B) Drainage of right lymphatic duct and thoracic duct into subclavian veins.

9. **** moves the same way as venous return
Movement of Lymph
Segments of vessels located between the valves contract rhythmically
Skeletal muscles compress vessels
**** moves the same way as venous return

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

11. Lymph Nodes Structure - Fibrous connective tissue capsule Function
Filter antigens and foreign bodies
Grouping
Cervical nodes
Axillary nodes
Mesenteric nodes
Inguinal nodes

12. Structure of a lymph node
Structure of a lymph node. (A) Arrows indicate the flow of lymph through the node. (B) Section of a lymph node as seen under the microscope (low power). (B, Reprinted with permission from Cormack DH. Essential Histology. 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2001.) 

13. The Spleen (gland and organ)
Cleanses blood
Filtration
Phagocytosis
Destroys old red blood cells
Produces red blood cells before birth
Is reservoir for blood
Has an unusually large supply of blood
Houses phagocytes and lymphocytes

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 (“the tonsils”)
- each side of soft palate
Pharyngeal tonsil (adenoids)
- behind nose/upper pharynx
Lingual tonsils
- posterior to tongue
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 – when they enter circulation they are:
Macrophages
Kupffer cells (lining of liver)
Dust cells (lungs)

18. Disorders of the Lymphatic System and Lymphoid Tissue
Lymphangitis – inflammation of the lymphatic vessels
Septicemia – blood poisoning resulting from pathogens entering the blood
Lymphadenitis – inflammation of the nodes
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
Elaphantiasis – caused by filariae worm blocking lymph vessel

20. Lymphadenopathy
Enlarged lymph nodes accompany certain diseases (cancer) 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 (benign or malignant)
Malignant disease
Hodgkin disease
Non-Hodgkin lymphoma