2: Tissues of the Immune System Flashcards
Primary organs
where leukocytes are differentiated from progenitor cells
Primary organ examples
bone marrow, thymus, bursa, Peyer’s patches
‘Secondary organs
sites where B and T cells are induced to function
Secondary organ examples
lymph nodes, spleen, bone marrow, Peyer’s patches, tonsils
Lymphoid organs
sites where lymphocytes develop and/or contact and respond to specific antigens
What cells differentiate in the bone marrow or bursa?
B and T cells
What cells differentiate in the thymus?
T cells
What cells differentiate in Peyer’s patches?
B cells
Peyer’s patches
organized tissues in lower GI tract
Stromal cells
support lymphopoiesis and myelopoiesis via both surface ligands and secretion of cytokines/growth factors
Interleukin 7
key cytokine that signals a B cell to be made
Where does blood formation occur in neonates who have not yet fully developed bone marrow?
spleen, liver, and lymph nodes
Terminal differentiation
presentation of self antigens drives T cells maturation
Tolerance
process that keeps you from attacking your own tissues as foreign
Hassall’s corpuscle
concentric epithelial cells that have a role in tolerance
Cortex
densely packed with immature T cells and B cells
Medulla
less dense collection of mature lymphocytes (plasma cells)
Trabuculae
divide the thymus into lobes
The ____ shrinks in size after sexual maturity
thymus
How are Peyer’s patches arranged
in follicles, with B cells central and T cells surrounding
What animals are Peyer’s patches more prominent in?
ruminants
3 main components of lymph nodes
- cortex
- medulla
- germinal center
Germinal center
site of B cell proliferation and activation
High endothelial venules (HEV)
where lymphocytes pass through to migrate into the lymph-node parenchyma, lack tight junctions
What is the largest lymphoid organ?
spleen
Primary purpose of spleen
storage and filtration of RBC
Red pulp of spleen
contains phagocytes
White pulp of spleen
contains lymphocytes, mostly B cells but also some T cells
Species that use spleen and liver as primary response to blood-borne pathogens?
rabbit, dog, mouse
Species that use lungs as primary response to blood-borne pathogens?
cat, calf, sheep
MALT
mucosa-associated lymphoid tissue
GALT
gut-associated lymphoid tissue
BALT
bronchus-associated lymphoid tissue
