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Lymphoid Organs II
Morrow 9/11/11 lecture -2 hrs
94
Histology
Undergraduate 4
03/07/2011

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Cards

Term
pulp cords
Definition
another name for cords of Bilroth, found within the red pulp of the Spleen
Term
palatoglossal & palatophayngeal arches

palatine tonsils are located between them
Definition
another name for the anterior and posterior tonsillar pillars (BONUS: what is located between them?
Term
not commonly, but they would have a foci of b cells
Definition
are there germinal centers in Peyer's patches?
Term
central Artery
Definition
areas of white pulp in the spleen are follicular areas +/- germinal centers with a central ____ in the middle
Term
1)antigen specific t-cell receptors
2)CD (cluster of differentiation) Surface markers
3) class 1 & 2 HLA (human leukocyte Ag) surface markers
Definition
as t cells mature, what 3 things do they express?
Term
appendix
Definition
blind ended sac, vestigial cecum
Term
surrounded by macrophages, called sheathed capillaries
Definition
blind ending capillaries in the spleen that lack endothelial lining, what are they surrounded by, what are they called?
Term
cannot see MALT, but can see Peyer's patches
Definition
can you see MALT without a microscope? how about Peyer's patches?
Term
thymic/hassals corpuscles (nurse cells don't really die-though they are bubble gum pink-, they hang around and form a collagen (& reticulin) web around themselves)
Definition
degenerate reticular and epithelial nurse cells
Term
only efferent lymph vessels draining lymph exit the thymus because the t cells are not full differentiated, there are no Afferent lymph vessels to the thymus.
Definition
describe afferent and efferent LYMPH vessels to the thymus
Term
they project into the lumen of gut in dome areas with cuboidal mucosa, also contain M-cells
Definition
describe the shape/layer of tissue that Peyer's patches are in?
Term
MALT
Definition
diffuse, unencapsulated lymphoid aggregates associated with mucosal surfaces
Term
not appreciable quantities of IgA
Definition
do Peyers patches make antibodies?
Term
it can, similar to lymph nodes
Definition
does MALT have germinal centers?
Term
no, thymus and lymph nodes do though
Definition
does the spleen have a cortex an medulla?
Term
yes, it is made of dense irregular CT (just like lymph nodes)
Definition
does the thymus have a capsule?
Term
stave cells
Definition
endothelial cells that line sinusoids on the spleen
Term
splenic nodules
Definition
enlarged germinal centers visible to the naked eye
Term
Nurse cells
Definition
epithelial cells, mainly within the cortex(also medulla) of the thymus that provide physiologic and metabolic support function and structural support
Term
thymic/hassals corpuscles
Definition
eosinophilic lamellated structures within the medulla of the thymus, important for identification of thymus tissue
Term
something gets caught in the appendix and plugs it up so neutrophils attack it and it swells up as the neutrophils die and form pus. This is painful, and if left untreated will cause the appendix to burst
Definition
how can appendicitis occur?
Term
via trabecular arteries which branch and form central arteries to white pulp(foci)
Definition
how do branches of the splenic artery enter the white pulp within trabeculae
Term
splenic vein
Definition
how is blood drained from the spleen?
Term
the lumen has skin like mucosa minus a stratum corneum
Definition
how would you identify the palatine tonsil in lab?
Term
apendicitis, you want to prevent secondary pertonitis when the appendix pops and all the dead neutrophils(pus) leak out
Definition
if the appedix is inflammed, what is it called? and why should you get an appendectomy?
Term
liver and bone marrow
Definition
if the spleen is removed (splenectomy) what organs take over its function?
Term
thymus and/or pancreas
Definition
if you have eaten sweet bread, what have you eaten?
Term
primarily b cells
Definition
in white pulp if it is a germinal center, what cells does it contain?
Term
not exactly, the base is supported by a cup-shaped hemicapsule
Definition
is the palatine tonsil encapsulated?
Term
not a distinct one
Definition
is there a cortex and medulla in the palatine tonsil?
Term
trabeculae
Definition
large thick bands of dense CT that extend into the body of the spleen
Term
spleen
Definition
largest lymphoid organ in the body
Term
1) b & t cell replication; manufacture of ab, ag removal [like lymph nodes]
2) removes particulate matter & aged or defective RBC's from circulation via phagocytosis
3) recycles Fe from Hb
4) hemopoesis in fetus
Definition
list the functions of the spleen
Term
1) production of mature, immunocompetent Th & Tc cells (helper and cytotoxic t cells)
2) clonal proliferation of Tc cells
3) development of immunologic self-tolerance (clonal deletion of self antibodies) -prevents autoimmune disorders
4) secretion of hormones regulating t-cell development & maturation
Definition
list the functions of the thymus
Term
thymus
Definition
lobular lymphatic organ located in the mediastinum
Term
Peyer's patches
Definition
lymphoid aggregates that contain large numbers of t cells
Term
M-cells? or MALT? not sure
Definition
responsible for antigen sampling and transfer from gut lumen into lymphoid follicles
Term
MALT
Definition
samples antigenic material, produces lymphoblasts, secretes antibodies
Term
Peyers patches
Definition
special type of MALT scattered throughout small intestine
Term
M-cells
Definition
squamoid enterocytes located on surface epithelium with microfolds instead of microvilli, contained within MALT
Term
marginal zone
Definition
the ____ of white pulp in the spleen functions as a site of antigen presentation & phagocytosis (contains a large number of macrophages, plasma cells to make antibodies, and t helper cells)
Term
lymph: b cells
thymus: t cells
Definition
the lymph tissue is mostly ___ cells, while the thymus is mostly ___ cells
Term
it lacks lymphoid follicles
Definition
the thymus is similar in appearance to lymph nodes, but how is it different?
Term
sheathed capillaries
Definition
this forms a non-continuous perivascular sheath or cuff that acts as part of filtering mechanism of the spleen, active in phagocytosis
Term
thymus
Definition
this lymph organ degenerates at puberty and is considered vestigial in adults
Term
periarteriolar lymphatic sheaths arteries or arterioles surrounded by t cells rather than b cells
Definition
what are PALS?
Term
MALT in the colon
Definition
what are Peyer's patches similar to histologically in the colon?
Term
either the depression the tonsil sits in OR the cracks on the surface where the epithelia has invaded the tonsil
Definition
what are tonsillar crypts?
Term
mostly b cells, plasma cells, and macrophages
Definition
what cells are found in the medulla of the thymus?
Term
stratified squamous nonkeratinized epithelium (looks like skin without stratum corneum)
Definition
what covers the luminal surface of the palatine and lingual tonsils?
Term
slender interlobular septa (aka trabeculae)

note: these are more pronounced than the ones in lymph nodes
Definition
what divides the thymus into lobules?
Term
phagocytize senescent RBC's
Definition
what do macrophages in red pulp of the spleen do?
Term
various hormones such as thymotaxin, thymosin, and thymopoeitin which attract, regulate, and promote t-cell proliferation into Th, Tc, and Ts(t supressor) cells
Definition
what do nurse cells secrete? what does this do?
Term
arterioles, terminate in 2-3 sheathed capillaries
Definition
what do penicillar arteries of the spleen branch into? and terminate in?
Term
more surface area for phagocytosis
Definition
what do the pulp cords provide the macrophages?
Term
perpendicular penicillar artery
Definition
what does the central artery of the spleen branch into (first)after it continues into the red pulp
Term
3rd pharyngeal pouch
Definition
what embryonic structure is the thymus derived from?
Term
endothelial slits between the stave cells
Definition
what feature of stave cells allows free passage of blood cells?
Term
invasion of the epithelium of the palatine tonsil into the tonsil tissue
Definition
what forms blind ended tonsillar crypts?
Term
it progressively atrophies
Definition
what happens to MALT distribution as you age?
Term
GALT in the gut, BALT in the resp. tract
Definition
what is MALT called in the gut? in the respiratory tract?
Term
a ring of immunologic protection for the GI and respiratory tracts

It is formed from the palatal, lingual, and pharyngeal tonsils
Definition
what is Waldeyer's ring? what does it do, and what forms it?
Term
PALS (periarteriolar lymphatic sheaths) in white pulp of the spleen
Definition
what is being described:
lack germinal centers, because no t cell proliferation
less well developed in humans that other species and require IHC stain to ID
term often used interchangeably with primary follicles in white pulp
Term
bacterial fermentation
Definition
what is the appendix used for in herbivores?
Term
pulp cords are more cellular and contain large numbers of RBC's, macrophages, and lymphs(b&t cells)
Definition
what is the difference between sinusoids and pulp cords in the red pulp of the spleen?
Term
contraction in some species and as a reservoir for RBC's
Definition
what is the function of the capsule of the spleen?
Term
dense fibro-elastic capsule; contains smooth muscle cells (for splenic contraction in some species)
Definition
what is the outer capsule of the spleen made of?
Term
it is an important hemopoetic organ during fetal development
Definition
what is the thymus used for in the fetus?
Term
when the thymus undergoes fatty infiltration and lymphatic depletion (at puberty)
Definition
what is thymic involution?
Term
white pulp is clusters(discreet nodules) of WBC's in the red pulp of the spleen
Definition
what is white pulp? where is it found?
Term
a continuous, antigenic CT sheath known as the blood-thymus barrier
Definition
what isolates the blood vessels of the thymus from the immune system?
Term
continuous epithelium on the inner surface of the capsule
Definition
what isolates the thymus from the rest of the immune system?
Term
red pulp
Definition
what kind of pulp is most of the spleen?
Term
thymus
Definition
what organ does development of immunologic self-tolerance (clonal deletion of self antibodies)
Term
thymus
Definition
what organ does maturation and CLONAL proliferation of t cells?
Term
thymus
Definition
what organ secretes hormones regulating t-cell development & maturation
Term
CT skeleton of reticular cells and reticular fibers
Definition
what supports pulp cords (CT)?
Term
a thin, basophilic marginal zone
Definition
what surrounds the areas of white pulp in the spleen?
Term
primarily IgA (mucosa/secretory associated antibodies) most other antibodies are associated with the blood
Definition
what type of antibodies does MALT produce?
Term
b cells
Definition
what type of cell (b or t) does the appendix mostly contain?
Term
b (b cells dominate everything except the cortex of the thymus & peyers patches- note: the medulla of the thymus is mostly b)
Definition
what type of cells are found in MALT mostly? (b or t?)
Term
epithelioreticular cells, reticular fibers, fibroblasts, macrophages, and plasma cells
Definition
what type of cells surround the endothelium and basement membrane of blood vessels in the thymus?
Term
sinuses in red pulp
Definition
when blood cells leave the sheathed capillaries via diapedsis, where do they go?
Term
fetal development
Definition
when is MALT formed?
Term
most common in the ileum and least common in the duodenum but found in all parts of the small intestine
Definition
where are Peyer's patches found?
Term
scattered throughout the parenchyma, may include germinal centers making them secondary (primary follicles if not)
Definition
where are lymphoid follicles in the palatine tonsil? what might they include?
Term
the highly cellular cortex(just like lymph nodes), t cells and macrophages
Definition
where are most of the lymphocytes concentrated in the thymus? what kinds of lymphocytes?
Term
at the base of the tongue
Definition
where are the lingual tonsils located?
Term
junction of the oral and pharyngeal cavities, within tonsillar crypts & between anterior and posterior tonsillar pillars
Definition
where are the palatine tonsils located?
Term
the oropharynx
Definition
where are the pharyngeal tonsils found?
Term
subepithelial CT of the lamina propria
Definition
where is MALT located in the layers of tissue?
Term
open
Definition
which model of circulation applies to the spleen?
Term
thymus, spleen,
Definition
which organs in this chapter are sites of hemopoesis in the fetus?
Term
appendix, peyer's patches, MALT
Definition
which structures in this chapter are diffuse lymphoid tissue?
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