1. The Lymphatic System & Immune Response
Exercise 35
The Lymphatic System & Immune Response

2. Objectives Components & functions of lymphatic system
Roles of B-cells, T-cells
Structure & function of lymph nodes
Localization of T-cells, B-cells, macrophages in lymph nodes
Antigen vs. antibody
Immunological memory, specificity, differentiation of “self vs. nonself”

3. Lymphatic System
Cells, tissues, & organs responsible for defending the body against
Environmental hazards (pathogens)
Internal threats (cancers)

4. Lymphatic System
Lymphocytes are primary cells responding to specific threats “specific defense” is the immune response

5. Lymphatic System Lymph (fluid c.t.) Lymphatic vessels Lymphoid tissues
Tonsils
Lymphoid organs
Lymph nodes, thymus, spleen
Fig. 22-1

6. Lymphatic System Functions
Transports LYMPH to the blood (lymphatic capillaries pick up this “leaked” interstitial fluid from tissues & takes it to the veins)
Fig. 22-2

7. Lymphatic System Functions
Protects the body:
Removes foreign material (i.e.: bacteria) from lymphatic system
“Police” of the body fluids
Replication/cell division of lymphocytes (T-cells, B-cells, etc.)

8. Lymphatic Vessels Right lymphatic duct SEE MODELS!!!
Drains lymph from upper right extremity, head, thorax
Into Rt Subclavian Vein
Fig. 22-4

9. Lymphatic Vessels Thoracic duct Drains lymph from rest of the body
Into L subclavian vein
Fig. 22-4

10. Lymphatic Vessels Rt lymphatic & thoracic ducts
Both empty lymph into venous circulation of blood
One-way system—only TOWARD the heart
Fig. 22-4

11. Lymphatic Vessels Cisterna chyli
Enlarged inferior “end” of thoracic duct
Receives lymph from the digestive viscera
Fig. 22-4

12. Lymph Nodes
Filter lymph as it’s transported through the lymphatic vessels
1000s throughout the body
Macrophages inside—phagocytize bacteria, cancer cells, etc. in lymph before entering bloodstream
Cervical, axillary, inguinal regions; Peyer’s patches in intestine

13. SEE MODELS!!!
Fig. 22-1

14. clusters of lymph nodules in small intestine
Peyer’s patches
clusters of lymph nodules in small intestine
SEE MODELS!!!
uhaweb.hartford.edu/ BUGL/immune.htm

15. Structure of Lymph node
Fig. 22-7

16. Peyer’s patch histology
Collection of lymphoid nodules in mucosa of small intestine
Peyer's Patches are largish, rounded areas located in the submucosa. They can be a bit difficult to spot: look for the slightly darker, purpler color and more speckled or grainy texture.
Lumen of small intestine

17. Lymph node histology

18. Lymphoid Tissue Tonsils Lingual Palatine Pharyngeal (adenoids)
(2) Base of tongue
Palatine
L, R: posterior inferior palate
Pharyngeal (adenoids)
(1) posterior superior wall of nasopharynx
Fig. 22-6
SEE MODELS!!!

19. Lymph Organs
Thymus: primary lymphoid organ
SEE MODELS!!!
Fig. 22-8

20. Lymph Organs
Spleen: secondary lymphoid organ
SEE MODELS!!!
Fig. 22-9

21. Lymphocytes: 2nd-most abundant WBCs
Fig

22. Stem Cells originate in bone marrow
B cells
Differentiate in
bone marrow
T cells
Differentiate in thymus
Then enter blood stream with specific things on cell’s surface,
and are cloned in lymph organs

23. Fig

24. Lymphocytes, continued:
After cloned and made many more replicates, each can form memory cells or effector/regulatory cells

25. Lymphocytes, continued:
B cell clones:
Memory B cells
Antibody-producing plasma cells
“humoral immunity” (work indirectly through antibodies released into blood/lymphstreams

26. Lymphocytes: T cell clones: Memory T cells
Cytotoxic T cells (directly attack virus-infected tissue cells)
Helper T cells (activate B cells & cytotoxic T cells)
Suppressor cells (can inhibit immune response)
“cellular immunity” (act directly, attack bacteria/viruses/parasites/cancer cells)

27. “FILTER”: ~99% of antigens are removed before enters bloodstream
Regions of T and B cells in lymph nodes
Macrophages in
Fig. 22-7

28. Antigen (Ag) vs. Antibody (Ab)
Antigens
Provoke an immune response
ANTI body GEN erators
Antibodies (immunoglobulins—Igs)
Produced by sensitized B cells or plasma cells in response to antigen presence
(proteins; IgM, IgG, IgD, IgA, IgE)
Antigen-binding site is specific

29. Fig

30. Important Immune Response Characteristics
Immunological Memory
Remembers foreign antigens it’s previously encountered, can react faster 2nd time (i.e.: chicken pox)
Specificity
Memory and antibodies very specific
Differentiation of “self” and “non-self”
Self = our own tissues, don’t alert immune response
non-self = foreign antigens, triggers immune response

31. Important Immune Response Characteristics
Just FYI---
Differentiation of “self” and “non-self”
Can malfunction
Autoimmune diseases (MS, Lupus, rheumatoid arthritis, juvenile diabetes, etc.)