lymphatic system histo Flashcards
cells in the reticular tissue meshwork of lymph nodes
- reticular cells
- dendritic cells
- macrophages
- follicular dendritic cells (FDCs)
reticular cells secrete ____ and ____
reticular fibers (type III collagen); ground substance
_____ wrap around bundles of reticular fibers; isolates structural components from parenchyma of lymphatic tissues/organs
elongated cytoplasmic processes
reticular cells play a ____ role
supporting
reticular cells express surface molecules and produce substances that attract:
T cells, B cells, and dendritic cells
dendritic cells are ____ derived ____
bone marrow; APCs
macrophages act as both ___ and ____
phagocytes; APCs
follicular dendritic cells (FDCs) have multiple, thin, hairlike branching _____ that interdigitate between ____ in germinal centers
cytoplasmic processes; B cells
_____ complexes adhere to FDC cytoplasmic processes via ____
antigen-antibody; Fc receptors
____ of lymph node divided into cortex and medulla
parenchyma
outer part of cortex, just deep to capsule
superficial (nodular) cortex
between superficial cortex and medulla
deep cortex (paracortex)
deep cortex (paracortex) contains the majority of ____ within the lymph node
T cells
the medulla consists of cords of _____ separated by _____
lymphatic tissue (medullary cords); lymphatic sinuses (medullary sinuses)
network of ____ and ____ traverses medullary cords and sinuses; serve as framework for the parenchyma
reticular cells; fibers
medullary cords contain:
lymphocytes (mostly B cells), macrophages, dendritic cells, and plasma cells
medullary sinuses converge near ____ and drain into _____
hilum; efferent lymphatic vessels
filtration of lymph in lymph node occurs within network of interconnected lymphatic channels called ____
sinuses
3 types of sinuses
- subcapsular (cortical) sinus
- trabecular sinuses
- medullary sinuses
about 90% of lymphocytes are conveyed in blood and enter the lymph node thru ____ in the ____
high endothelial venules (HEVs); deep cortex
endothelium is almost always _____, however, in lymphatic tissues, the endothelium of postcapillary venules is ____
simple squamous epithelium; cuboidal
flow of lymphocytes from blood thru lymph node
HEVs > deep cortex > superficial cortex > back thru deep cortex >medulla > efferent lymph vessel
flow of lymphocytes from lymph thru lymph node
afferent lymph vessel > subcapsular (cortical) sinus > trabecular sinus > medullary sinus > efferent lymph vessel
developing lymphocytes (thymocytes) in the thymic cortex occupy spaces within extensive meshwork of _____
epithelioreticular cells
____ are also present within thymic cortex to phagocytose ____
macrophages; apoptotic T cells
thymic medulla contains large number of ____ and ____
epithelioreticular cells; loosely packed T cells
_____ form the most characteristic feature of the medulla, which is _____
type VI epithelioreticular cells; thymic (Hassall’s) corpuscles
