Thymus/Lymph Nodes/Spleen

Question 1

what composes the cortex of the thymus?

Answer 1

T lymphocytes, epithelial reticular cells and macrophages

Question 2

why do reticular cells appear epithelial?

Answer 2

attach to one another through desmosomes, and cytoplasm contains bundles of keratin filaments

Question 3

what comprises of the medulla of the thymus?

Answer 3

same cell populations as cortex (T cells, reticular cells, and macrophages)
*contains larger number of epithelial reticular cells

contains hassall’s corpuscles

Question 4

what is the site of differentiation of T lymphocytes?

Answer 4

thymus

Question 5

what percentage of T cells undergo apoptosis in the thymus and why?

Answer 5

95%, T cells that cannot recognize antigens or those that recognize self antigens are destroyed

Question 6

what happens if lymphocytes that recognize self antigens are not destroyed?

Answer 6

autoimmune disease

Question 7

are thymus capillaries fenestrated or nonfenestrated?

Answer 7

nonfenestrated with a thick basal lamina

Question 8

does the thymus have afferent lymphatic vessels?

Answer 8

no, they do not filter lymph. but does contain efferent lymphatic vessels

Question 9

what is the function of the lymph nodes?

Answer 9

provide major defense of the body against microorganisms and the spread of tumor cells throughout the body

Question 10

what is the function of the lymphatic vessels?

Answer 10

filters through which all tissue fluid-derived lymph passes on its way to blood circulation

Question 11

afferent lymphatic vessels

Answer 11

carry lymph toward the node and enter it on the convex side of the capsule

Question 12

efferent lymphatic vessels

Answer 12

drain lymph away from the node at the hilum

Question 13

what is the function of the spleen?

Answer 13

1. production of immunological responses against blood-born antigens
2. removal of particulate matter and aged or defective blood cells (RBC) from circulation