Flashcards in Lymphatic System I & II Deck (71)
How are the functions of the lymphatic system carried out by?
what cells arise from lymphoid stem cells?
B lymphocytes -- plasma cells
what are the two types of T cells?
Helper CD 4+
Cytotoxic CD 8+
what do helper CD 4 activate?
CD 8+ with IL-2 production
what types of lymphocytes are capable of recirculation?
T cells - 60-70% of circulating lymphocytes
Where are B cells produced?
what do NK cells attack?
virally infected cells
what types of cells carryout innate responses?
what are the characteristics of innate responses?
fast and non specific
does not produce memory cells
What cells are involved in adaptive response?
B and T cells - depends on the initial recognition of antigens
what are the characteristics of adaptive responses?
slower and specific
produces memory cells
when is antibody mediate immunity (humoral immune response) important?
what cells are involved in humoral immune responses? what are the effectors?
helper T cells
When is cell mediated immunity important?
viral and fungal infections - involved in the rejection of transplanted organs and tissue grafts
what are the cells involved in cell mediated immunity? what are the effectors?
Cytotoxic T cells
T cells (effector)
what is the characteristic of diffuse, loose lymphoid tissue?
few lymphocytes present
initial immune response
found in lamina propria
what is the characteristic of diffuse, dense lymphoid tissue?
many lymphocytes are present
contained in meshwork of reticular fibers
what does the GC indicate?
lymphatic tissue response to antigen
what does a primary nodule consist of?
not ever exposed to antigen
found in newborns only
what does a secondary nodule consist of?
germinal cortex (GC)
what is the germinal cortex?
where lymphocytes undergo proliferation
what is a follicular dendritic cell?
Not an antigen presenting cell
help keep the antigen-antibody complex in place
what is the major cell found in lymphoid nodules?
what cells are found around the periphery of the lymphoid nodules?
where does the thymus originate from?
3rd pharyngeal pouch
what is important to note about the thymus?
no afferent lymphatics - just efferent
why? - because there is no filter, just production and migration through efferent
what type of cells make up the epithelial component of the thymus?
ERC - epithelial reticular cells
what are thymocytes?
immature T lymphocytes
what are the parenchyma of the thymus?
Cortex and medulla