lymphatic Flashcards
what type of tissue is lymphatic
specialized CT
what differentiates a secondary from a primary lymph nodule of a lymph node
a lighter-staining germinal center
3 germinal center components
dendritic cells (APC’s), macrophages, proliferating B cells, some memory B cells
corona components
B-memory cells
what does the space between the corona and germinal center contain?
T-helper cells
Peyer’s patches
lamina propia of the ileum. permanent nodule. indicates leaky gut. pushes villi into mounds
what separates tonsils from the underlying muscle
partial fibrous CT capsule
3 non-encapsulated lymph nodule locations
tonsils, appendix, Peyer’s patches (ileum)
hilum or hilus
point where blood vessels enter the lymph node, site of efferent lymph vessel
order of sinusoids into which lymph flows in a node
- afferent vessels 2. subcapsular sinus 3. trabecular/corticoid sinus 4. medullary sinus 5. efferent vessel
what cells for the sinuses of lymphnodes
reticular CT cells, dendritic cells, macrophages
periarteriolar lymphatic sheath (PALS)
surrounding the splenic and trabecular arteries, dense with T-cells
high endothelial venule
in deep cortical (adjacent to medulla) region of lymph nodes, cortex/medulla jnct of thymus. a POSTCAPILLARY VENULE recognized by T cells to associate into the THYMUS-DEPENDENT ZONE
cell types in the medulla of lymph nodes
B cells, plasma cells (their home for 14 days)
where are T helpers in a nodule
between the corona and the germinal center
what type of fiber is abundant in lymph nodes
reticular fibers support the lymphocytes
where can one find nodules within the lymph node
in the cortex
what is the purpose of the thymus
proliferates T cells, sends differentiated but immuno-incompetent T cells out to colonize other lymph organs, programs some T cells
The two components of white pulp of the spleen
the PALS (periarticular lymphoid sheath) containing antigen-presenting dendritic cells and T-cells, and the nodules supplied by follicular arteries containing B-cells, plasma cells, IgG’s
what is NOT present in the spleen compared with other lymph organs
no afferent lymph vessels
what are the components of red pulp
the dilated sinusoid (sinusoidal veins supplied by penicullar arteries) and splenic cords
what is unique about splenic sinusoids
they havee basement membranes that form anastomosinng bands around the slitted (leaky) endothelium
which lymph organ contains no reticular fibers
thymus - it only has endothelioreticular cells with tight junctions and long cytoplasmic processes
how does the thymic cortex restrict any macromolecules from entering
because there is a ring of macrophages between the basal lamina of the endothelium and the basal lamina of the ERC’s AND a continuous ERC layer
organization of the thymus
CT CAPSULE: trabeculae that make cortex-containing lobes
CORTEX: outer T-cells inner macrophages supported by thymosin-secreting ERC’s
MEDULLA: continuous through all lobes, containing THYMIC CORPUSCLES of ERC’s that expand with age
two functions of lymph nodes
process lymph fluid for antigens and waste, make B and T cells immunocompetent
dendritic cells
mildly phagocytotic antigen/antibody complex-presenting cells of the white pulp, Peyer’s Patches, and Lymph nodes
predominant cells of the cortex and medulla of lymph nodes
B cells
predominant cells of the deep cortex of lymph nodes
T cells
