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72 Cards in this Set
- Front
- Back
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What germ layer is the thymus derived from?
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Endoderm and Mesoderm
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What part of the thymus is derived from mesoderm?
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Lymphocytes
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What part of the thymus is derived from endoderm?
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Epithelial recticular cells
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Which pouch gives rise to the thymus?
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3rd pharyngeal pouch
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What cells infiltrate the thymus at puberty?
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Adipose Cells
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What hormone can restimulate the thymus after puberty?
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LHRH
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What cells at puberty decrease in differentiation and proliferation?
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T-cells
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What happens to the thymus during puberty?
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a. Involution
b. Atrophy c. Increase of adipose in the thymus. |
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How long does it take for the thymus to completely mature?
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It is fully functional and mature at birth.
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During the development of the thymus what cells invade it?
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CFU-Ls
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Which of the following is NOT a feature of the capsule:
A. Efferent Lymph Vessel B. Afferent Lymph Vessel C. Arteries D. Veins E. All are found in the capsule. |
B. There are no afferent lymph vessels in the entire thymus.
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Which cells are not found in the capsule of the thymus?
A. Fibroblast B. Granulocytes C. Mast Cells D.Adipose Cells E. All are found in the capsule. |
E. All are found in the capsule.
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What divides the thymus into incomplete lobules?
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Trabeculae
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What are the two parts of the thymus lobules?
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Cortical Cap
Medullary tissue |
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Where do T cells develop in the thymus?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
C. Cortex
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Where do T-cells completely mature?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
D. Medulla
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What layer are thymic (Hassall's) corpuscles found?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
D. Medulla
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Inner, eosinophilic region of paranchyma of the thymus?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
D. Medulla
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Outer, basophilic region of paranchyma of the thymus?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
C. Cortex
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Site of migration of incompentent T-cells?
A. Capsule B. Trabeculae C. Cortex D. Medulla |
C. Cortex
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Are there reticular cells in the thymus?
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No, there are epithelioreticular cells which have reticular cell-like qualities.
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What characteristics give epithelioreticular cells reticular cell-like qualities?
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Framwork for lymphocytes (t-cells)
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What characteristics give epitheliorecticular cells epithelial cell-like qualities?
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1. Intermediate filaments
2. Contains Intercellular Junctions |
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What type of reticular cells express MHC I and II?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
F. Type II and III
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What type of reticular cells are involved with T-cell education?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
F. Type II and III
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What type of reticular cells contain occluding junctions?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
E. Type I and III
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What type of reticular cells acts as a barrier?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
E. Type I and III
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What type of reticular cells compartmentalizes the cortex?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
B. Type II only
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What type of reticular cells are found in the cortex?
A. Type I B. Type II C. Type III D. A & B E. A & C F. B & C G. All the above. |
G. All the above
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What type of reticular cells found in the medulla?
A. Type IV B. Type V C. Type VI D. A & B E. A & C F. B & C G. All the above. |
G. All the above
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What is Crosstalk?
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T-cells control microarchitecture of thymic epithelioreticular cells.
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2 hormones produced by Hassall's corpuscles?
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Thymosin
Thymopoietin |
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Predicted function of Hassall's corpuscles?
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Produced IL-4 and IL-7
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Characterize Hassall's corpuscles.
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a. Located only in the thymic medulla.
b. Keratinized Center. c. Converts auto-reactive T cells to regulatory T cells |
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Select the correct order:
1. CFU-L stem cells. 2. Migrate to thymic Cortex 3. Migrate to thymus medulla via postcapillary venule. |
1,3,2
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Which epithelioreticular cells form Hassal's corpuscles?
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Type VI
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What is the destinguishing feature of the thymic medulla?
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Hassall's corpuscles
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What is the only lobulated lymphatic organ?
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Thymus
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Pick out the true statement:
A. The thymus contains lymphatic nodules. B. The thymus has efferent lymphatic vessels only. C. B-cells aid in T-cell education in the cortex of the thymus. D. Thymus contains Hassal's corpuscles comprised of type VI reticular cells. E. None of the above are true. |
B is correct.
No lymph nodules No B-cells in the thymus No reticular cells in the thymus Hassal's corpuscles are comprised of type VI EPITHELIOrecticular cells. |
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These cells are between the cortex of the thymus and the CT of the capsule
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Type I
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These cells function as a barrier in the thymus.
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Type III
Type IV |
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These cells compartmentalize in the thymus.
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Type II
Type V |
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These cells are between the cortex and the Medulla of the thymus.
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Type III
Type IV |
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These cells are found only in the medulla of the thymus.
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Type V
Type VI |
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These cells are found only in the cortex of the thymus.
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Type I
Type II |
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These cells are found between the parenchyma and trabeculae in the thymus.
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Type I
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These cells are involved in T cell education in the thymus
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Type II
Type III Type V Type VI (possibly) |
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These cells act as a barrier in the thymus.
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Type III
Type IV |
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These cells in the thymus form tight junctions with itself and other types of epithelioreticular cells.
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Type III
Type IV |
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These cells in the thymus only form tight junctions with cells of the same type.
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Type I
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Choose the correct statement.
A. The thymus has no lymph filter. B. Cortex is the site for the single positive stage in T-cell education. C. Dr. Meek likes females. D. CD2 is used during the first selection process. |
A. is correct
B. cortex does double negative and double positive, C. Self explanatory D. CD2 is used during the double negative stage, but the double positive stage is the actual first selection process. |
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What two CDs are expressed during the double negative stage of T-cell education?
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CD 2
CD 7 |
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What cells prest with self and foriegn antigens during the double positive stage of T-cell education?
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type II and III epithelioreceptor cells
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What CDs are expressed during the double positive stage of T-cell education?
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CD 3
CD 4 CD 8 TCRs |
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What are the two things that T-cells have to be able to do to pass from the cortex to the medulla?
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1. Recognize Self MHC
2. Recognize any type of Ag |
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Which is larger the percentage of those who dislike histo or number of T cells that fail their education?
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This is actually close, but the edge goes to haters of histo (around 99%) vs the (98% of ) T cells that fail their education.
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Put the following in sequential order by when they are expressed.
1. CD1 2. CD2 7 3. CD 4 or 8 only 4. CD 3 4 8 |
2, 1, 4, 3
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Put the following in order of sequence. Then determine location of each.
1. Negative Selection 2. Double Positive Stage 3. Single Positive Stage 4. Double Negative Stage |
4. double negative (cortex)
2. double positive (cortex) 1. Negative Selection (medulla) 3. Single positve stage (medulla) |
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Where does involution on the thymus begin?
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Cortical Zone
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After involution does the thymus become totally nonfunctional?
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NO!
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Which is more resistant to involution of the thymus Hassall's corpuscles or lymphocytes?
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Hassall's corpuscles
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Name the hormones required for T cell maturation:
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Thymosin
Thymopoietin Thymulin Somatotropin Thymic Humoral Factor Thyroxiin Adrenocorticosteroids |
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Where is somatotropin produced?
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Pituitary
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Where is thyroxin produced and what is its function?
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Thyroid
Stimulates thymulin production |
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What produces thymulin?
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epithelioreticular cells
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Where are adrenocorticosteroids produced and what is there function in T cell maturation?
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Adrenal Gland
depress T cell formation in the thymus |
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What substances are secreted by the epithelioreticular cells that promote T cell education (not maturation)?
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Interlukins
Colony Stimulating Factors Interferon gamma Thymosin Thymopoietin |
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What are some examples of autoimmune disease?
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Lupus
Graves Disease Rheumatoid Arthritis |
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What do patients usually die from in DiGeorge Syndrome?
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Tetany or Uncontrollable infection
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What causes tetany in DiGeorge Syndrome?
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Absence of parathyroid gland
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What is considered the major structural component of the blood-thymus barrier?
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Lining endothelium of the capillary wall.
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What is the purpose of the blood-thymus barrier?
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Protects T cells in cortex from Antigen contact
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