chapter 7 (2nd lymphoid organs/lymphocyte trafficking) Flashcards
what are the primary lymphoid organs
bone marrow and thymus
where do B and T cells originate
Bone Marrow
in what endocrine organ do T cells develop
Thymus
what are the secondary lymphoid organs
Lymph nodes, spleen, mucusal-associated lymphoid Tissue(MALT)
where is mucosal-associated lymphoid tissue found
GI tract, Respiratory tract, Reproductive tract
what secondary lymphoid organs have lymphoid follicles
ALL
roughly how many lymph nodes are in the body
500-600
where are lymphoid follicles common
within all SECONDARY lymphoid organs
what type of lymphoid follicles have a loose network of follicular dendritic cells (FDC)
Primary
are follicular dendritic cells and dendritic cells the same?
no
what type of lymphoid follicles are rich in naive B cells or memory B cells
Primary
what is referred to as an “island of FDCs in a sea of B cells”
Primary lymphoid follicles
when does a primary lymphoid follicle become a secondary lymphoid follicle
after antigen stimulation
what creates a germinal center
replication and differentiation of secondary lymphoid follicles
what are Activated dendritic cells
WBC’s in bone marrow that migrate to tissues
what do follicular dendritic cells do
catch and display antigen to B cells
how does a follicular dendritic cell catch and display antigen to B cells
receptors bind the Fc region of antibodies
what binds follicular dendritic cells to invaders
complement protein and antibodies
what do follicular dendritic cells receptors bind to
complement proteins, and the Fc region of antibodies
why do follicular dendritic cells attach to and hold opsonized antigens
they hold the close to each other allowing BCR’s to cluster and cross-link more easily
once a B cell is activated in a lymph nodule, how long does it take for the number of B cells to double
6 hours
what may join in with the FDC’s to activate B cells in the germinal center
helper T cells
what creates a dark zone in the germinal center
proliferating B cells push aside other B cells
when a B cells becomes a plasma cell in the germinal center where does it go
to bone marrow
in a germinal center what fine tunes the Fab reginos
somatic hypermutations
where are new mutations tested in germinal centers
the light zone
where is class switching likely to occur within the germinal centers
the dark zone
within the germinal centers new mutations with a lower affinity of BCR B cells die by what process and are eaten by what?
they die by apoptosis and are eaten by macrophages
how to antigens enter a lymph node
via blood or lymph
how does blood enter the lymph nodes
via an arteriole
how does a lymphocyte leave the blood
enters a lymph node via high endothelial venules (HEV)
where does lymph first enter a lymph node
subcapsular sinus
what is the subcapsular sinus lined with
macrophages
