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14 Cards in this Set
- Front
- Back
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where is the thymus located
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in the mediastinum
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what happens afer puberty |
the thymus deteriorates, diminishing effectiveness of the immune system |
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how many lobes is the thymus divided into |
two thymic lobes |
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what divides the thymic lobes |
septa divide the thymic lobe into lobules |
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what is the makeup of thymic lobules |
a dense outer cortex and a pale central medulla |
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what do lymphocytes do in the thymus |
they divide in the cortex of the thymus then migrate into the medulla |
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how do mature T cells leave the thymus |
by medullary blood vessels |
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what surrounds the lymphocytes in the thymic cortex |
dendridic cells |
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what do the dendridic cells do in the thymus |
maintain the blood-thymus barrier in the cortex |
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what do thymic hormones stimulate in the thymus |
stem cell divisions t cell differentiation |
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describe the medulla in the thymus |
it contains fewer lymphocytes and has no blood-thymus barrier so that T cells can enter or leave the blood |
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what are Hassall's or Thymic Corpuscles |
keratinized epithelial cells that form concentric layers in the thymic medulla they are involved in regulatory T cell development and prevent autoimmunity |
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thymosins do what |
promote development of lymphocytes |
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what is DiGeorge Syndrome |
a congenital absense of the thymus marked by serious combined immuno-deficiencies (SCIDS) bubble boy |
