1. Medical School Histology Basics Lymphoid System
VIBS 289 lab
Larry Johnson Texas A&M University

2. EXAMPLES OF IMMUNE RESPONSE
REACTION AGAINST MICROORGANISMS: BACTERIA, VIRUSES, PARASITES
REACTION AGAINST TUMOR CELLS
ALLERGIC REACTIONS: HAY FEVER, POISON IVY
AUTOIMMUNE REACTION: ARTHRITIS, TYPE I DIABETES
GRAFT REJECTION
Appendix
32412

3. OBJECTIVES PURPOSE OF THE IMMUNE SYSTEM CELLULAR BASIS OF IMMUNITY
EFFECTORS OF RESPONSE
INDUCTION OF THE RESPONSE
ONTOGENY

4. FUNCTIONS OF THE IMMUNE SYSTEM
PROTECTION AGAINST FOREIGN INVADERS INTO BODY
PRODUCE / PROTECT GERM FREE ENVIRONMENT OF THE BODY

5. Three Key Steps of Combating Infections
reak the cycle of transmission
ill the infectious agent
ncrease host resistance
e.g., increase immunity
of host

6. Lines of Defense First Line: Physical Barrier reak the cycle
Skin: Stratum Cornium
HCl In Stomach
Mucus In Intestines
reak the cycle
of transmission

7. Lines of Defense Second line: Phagocytes at work
Neutrophils to ill the infectious agent
Monocytes - macrophage

8. Characteristics of Immunity
ncrease host resistance through Immunity
Characteristics of Immunity
Acquired - requires exposure to antigens
Specificity - response is unique to exposure
Memory - remembers previous exposure

9. Characteristics of Immunity
Acquired -
Must be developed
Specificity -
Antibodies made are specific to specific molecules on the antigen of exposure

10. Characteristics of Immunity
Memory: quick second response
Long lived cells

11. Types of Immune Response
Antibody: mediated
Glycoproteins recognize and bind to antigens
Cell: mediated
Specifically active cells recognize cell - bind antigens

12. Slide 32583, see colonies of developing cells and for blood vessels in the bone marrow

13. Smear of bone marrow cells
112
Smear of bone marrow cells

14. thymus
Bone marrow

15. Thymus

16. Thymus, newborn 123 Medulla Cortex
Outer darkly staining areas (cortex) and lighter central areas (medulla).
Medulla
Thymocytes
Cortex
Medulla
Continuous capillaries, sheathed by epithelial reticular cells around each, characterizes blood vessels in the thymus cortex and is responsible for the blood thymus barrier. Also there are no afferent lymphatics in the thymus.

17. Thymus, newborn 123 Cortex epithelial reticulum cells
Mitotic figures frequently, which reflect the high proliferative rate of these cells.

18. THYMUS RETICULUM FRAMEWORK - EPITHELIUM Blood-thymus barrier in cortex
Epithelial reticulum cells
Hassall's
corpuscles

20. 116 Lymph node Large round structures (follicles), Cortex Afferent
lymphatic
duct
Medulla
Germinal
center,
Capsule
Capsule
Subcapsulary sinus

21. Lymph node 116 Subscapular space Capsule Afferent lymphatic duct

22. Predominantly T lymphocytes
Predominantly B lymphocytes, around germinal center
Perifollicular
area
Germinal center
High endothelial venules = sites where blood-borne lymphocytes enter the node.

23. Parafollicular region
Follicle
116
High endothelial venule
Part of follicle
Typical
flat
endothelium
= Site of lymphocyte
entry into the lymph node (one way street)

24. INDUCTION OF RESPONSE
PERIPHERAL ORGAN NEEDED TO GET ANTIGEN AND RESPONSIVE CELL TO INTERACT
LYMPHOCYTE RECIRCULATING
APPROPRIATE CONTEXT

25. 19754 Vinous sinus in lymph node
Medullary cords

26. Parafollicular
region
Efferent lymphatic
duct?
116

27. Tonsil

28. Tonsil
419

29. Tonsil
419

30. Esophagus and trachea, monkey
242
Esophagus and trachea, monkey

31. 145
Fundic stomach

32. Plasma cells large intestine in Colon, monkey
153
Plasma cells large intestine in Colon, monkey

33. Appendix (Slide 32412). 32412 Lymphoid tissues
Lymphoid tissues are important in the defense against ingested micro-organisms

34. Spleen

35. Spleen (reticulum stain)- capsule and reticulum fibers
218
Spleen (reticulum stain)- capsule and reticulum fibers

36. Spleen 122 Venous sinuses, and Billroth's strands Capsule
the red pulp.
Primary function
Of the spleen is
filtration of blood.
white pulp
Spleen has no
afferent lymphatics
Central artery

37. 117 Spleen Penicillar arteries in marginal zone Marginal zone
Follicles
White pulp
Central artery
Red pulp
Venous sinuses
Billroth's strands

38. Spleen
122
central artery
PENICILLARY ARTERIES
Marginal zone

39. 218
Spleen (reticulum stain)- reticulum fibers in strands between venous (blood) sinus

40. Litteral cells of spleenic venule Spleen #19752 (UT117?)

41. Spleen
Littoral cells: picket-fence type endothelial cells of vascular sinus
Penicillar arteries
Billroth’s
strand or spleenic strand

42. Bone marrow 19761 Lymphocyte is a main player of immune response Blood
in vessel

43. Life Cycle of Lymphocytes
Fetal organs
Bone marrow
Primary lymphoid organs
(Antigen independent development)
- Thymus – T lymphocytes
- Bone marrow - B lymphocytes
Secondary lymphoid organs
(Antigen dependent development)
Lymph nodes
Lymphoid nodules
Spleen

44. In summary

45. Questions on the lymphoid system
1. The main purpose(s) of lymphocyte traffic, the circulation of lymphocytes throughout the body, is:
a. to place the responsible lymphocytes in the region of specific antigens
b. to stimulate lymphocyte growth through meiosis
c. to clean out the lymphatics ducts
d. a and b
e. a, b, and c
2. The function(s) of the spleen include:
a. clean the blood of particulate matter
b. to remove worn red blood cells
c. to remove ribosomes from reticulocytes
3. Which lymphatic organ(s) contain(s) penicilliary arteries or both afferent and efferent lymphatic vessels?
a. lymph node
b. spleen
c. thymus

46. Many illustrations in these VIBS Histology YouTube videos were modified from the following books and sources: Many thanks to original sources!
Bruce Alberts, et al Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
Bruce Alberts, et al Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY.
William J. Banks, Applied Veterinary Histology. Williams and Wilkins, Los Angeles, CA.
Hans Elias, et al Histology and Human Microanatomy. John Wiley and Sons, New York, NY.
Don W. Fawcett Bloom and Fawcett. A textbook of histology. W. B. Saunders Company, Philadelphia, PA.
Don W. Fawcett Bloom and Fawcett. A textbook of histology. Chapman and Hall, New York, NY.
Arthur W. Ham and David H. Cormack Histology. J. S. Lippincott Company, Philadelphia, PA.
Luis C. Junqueira, et al Basic Histology. Lange Medical Publications, Los Altos, CA.
L. Carlos Junqueira, et al Basic Histology. Appleton and Lange, Norwalk, CT.
L.L. Langley, et al Dynamic Anatomy and Physiology. McGraw-Hill Book Company, New York, NY.
W.W. Tuttle and Byron A. Schottelius Textbook of Physiology. The C. V. Mosby Company, St. Louis, MO.
Leon Weiss Histology Cell and Tissue Biology. Elsevier Biomedical, New York, NY.
Leon Weiss and Roy O. Greep Histology. McGraw-Hill Book Company, New York, NY.
Nature ( Vol. 414:88,2001.
Arthur C. Guyton,1971.Textbook of Medical Physiology W.B. Saunders company, Philadelphia, PA
WW Tuttle and BA Schottelius Textbook of Physiology C.V. Mosby Co.
A.L. Mescher Junqueira’s Basis Histology text and atlas, 13th ed. McGraw

47. Park near Liberty Hill, TX

48. The end of