1. Lymphatic System Tissues, organs, vessels and a fluid called lymph
similar to interstitial fluid
Diffuse lymphatic tissue
Tonsils, mucosa associated lymph tissue and red bone marrow
Organs involved
thymus
spleen
lymph nodes

2. Functions of the Lymphatic System
Draining excess interstitial fluid & plasma proteins from tissue spaces
Transport of some nutrients and hormones
Immunity –specific defense
recognize microbes or abnormal cells & respond by killing them directly or secreting antibodies that cause their destruction

3. Formation & Flow of Lymph
Fluid & proteins filtered from blood capillaries are collected by lymphatic capillaries & returned to the blood
Muscle contraction and breathing promote flow of lymph
Lymphatic vessels empty into veins in shoulders

4. Lymph Circulation Lymphatic capillaries
Capillaries are closed-ended tubes in tissues
One-way valves
Pickup fluid (lymph) from Tissues

5. Lymph Circulation LymphaticVessels Lymphatic Trunks
Lymph passes from capillaries into lymph vessels
Resemble veins with thin walls & valves
Afferrent lymphatics carry lymph to nodes
Efferent lymphatics carry lymph from nodes
Lymphatic Trunks
Lymph passes from lymphatic vessels into trunks
*Bronchomediastinal, jugular, subclavian, intestinal and lumbar trunks

6. Lymph Circulation Lymphatic ducts
Two ducts drain lymph from lymphatic trunks into the subclavian veins
Thoracic Duct: Larger one that drains most of body lymph into the left subclavian vein
Right Lymphatic Duct: Smaller one that drains right side of head, right shoulder and right arm into the right subclavian vein

7. Lymph Circulation Right Lymphatic Duct------
Thoracic Duct
Right Lymphatic Duct------
Thoracic Duct

8. Lymphatic Pathways Interstitial fluid  Lymph Capillaries 
Afferent Lymphatic vessels  Lymph Nodes
Efferent Lymphatic vessels  Lymphatic
Trunks Lymphatic Ducts  Subclavian
Veins

9. Lymphocytes B-cell lymphocytes T-cell lymphocytes
Respond to antigens by dividing to produce
Plasma cells: Antibody secreting cells
Memory B-cells
T-cell lymphocytes
Cytotoxic T-cells that kill antigen-bearing cells
Helper T-cells that help activate other T-cells and B-cells
Memory T-cells
Natural killer (NK) lymphocytes can kill invading cells and tumor cells without need to respond to antigens – nonspecific defense

10. Diffuse Lymphatic Tissues
Lymphatic nodules – MALT (Mucosa Associated Lymph Tissues)
lymphatic nodules within the digestive and respiratory systems
Small intestine -Peyer's patches
Appendix
Bronchi of respiratory tract

11. Diffuse Lymphatic Tissues
Tonsils
Located in and around throat
Tonsilar crypts
Functions
Crypts Trap microbes
Mount immune response against inhaled and ingested microbes

12. Lymph organs Lymph nodes Structure Location Functions
Throughout body but concentrated in groin, neck, armpit
Functions
Filter Lymph
Mount immune response

13. Lymph Node Distribution

14. Lymph Organs Thymus Located in mediastinum above heart
Large in infants atrophying with age
Function
Thymosin hormones for T-cell maturation

15. Spleen Located in upper left quadrant to left of stomach Functions
Filters blood
Produces lymphocytes
Stores iron and platelets

16. Defense Non-specific Defense First Line Defense: External Skin
Mucous Membranes
Tears
Saliva
Stomach acid

17. Non-specific Defense Second Line Defense: Internal
Antimicrobial proteins
Interferons – antiviral
Complement – immunity, allergies and inflammation
Natural killer (NK) cells
Lymphocytes
kill microbes and tumor cells
Phagocytes
Wandering phagocytes
Fixed phagocytes

18. Non-specific Defense Second Line Defense: Internal Inflammation
Mast cells and basophils release chemicals
Arterioles vasodilate – more blood to site
Increased capillary permeability – more fluid into tissues

19. Non-specific Defense Inflammation results in Redness Heat
Swelling (edema)
Pain
Healing

20. Specific Defense: Immunnity
Study of immunity is immunology
Immunity versus non-specific defense
Specificity: responds to specific antigens
Memory: Second exposure to antigen causes a stronger response
Antigens
Foreign (non-self) chemicals
Cause immune response

21. Immunity B-cell and T-cell lymphocytes responsible for immunity
Two types of immune responses
Cell mediated immunity: T-cells respond to intracellular antigens such as virus infected cells and tumor cells
Antibody mediated immunity: B-cells respond to extracellular antigens such as bacteria

22. Cell Mediated Immunity
T-cells processed by thymus gland
Two types of T-cell lymphocytes
CD4 cells (Helper cells)
Activated when antigen presented by antigen presenting cell (APC) cell
Develops into helper T-cells and memory cells
Helper T-cells must stimulate CD8 cells for them to become fully activated killer T’s
CD8 cells (Cytotoxic cells)
Activated by contact with virus infected body cell
Develop into killer t-cells and memory cells

23. Cell Mediated Immunity
Cytotoxic T’s leave lymphatic tissue to search for and destroy virus infected cells, tumor cells and tissue transplant cells on contact

24. Cell Mediated Immunity

25. Antibody Mediated Immunity
B-cell lymphocytes stay in lymph tissues
Extracellular antigen enters lymph tissue and binds to B-cell receptors
B-cells become activated
B-cells divide (clone) to form plasma cells and memory cells
Helper T-cells bind to antigen on B-cells and “help” stimulate plasma cell and memory cell formation

26. Antibody Mediated Immunity
Plasma cells secrete various types of antibodies
Antibodies bind to the specific antigen that activated its parent B-cells
Antibodies cause the destruction of the antigen

27. Antibody Mediated Immunity
Antibodies destroy antigens by
Neutralizing antigens such as toxins
Agglutinating (clumping) and precipitating (removing from solution) antigen bearing cells
Activating the complement proteins that destroy the antigen by various means
Enhancing phagocytosis

28. Antibody Mediate Immunity

29. Immune Response Primary Response
After an initial exposure to an antigen a slow rise in antibodies production occur first as immunoglobulin M (IgM) then (IgG)
Secondary Response
After a subsequent exposure the antibodies production is far greater and is mainly (IgG)

30. Summary of Cell and Antibody Mediated Immunity