Lymphoid Tissue 2 Flashcards
What is the largest lymphatic organ?
spleen
What is the blood supply of the spleen?
splenic artery and vein
What does the splenic artery supply?
spleen, parts of stomach, and pancreas
What two veins connect to form the portal vein?
splenic and superior mesenteric vein
What are functions of spleen?
-b and t cell replication
-remove particulate matter and remove old or defective RBC
-recycle iron from HB
-hematopoiesis in fetus
If spleen is removed, what takes over the functions?
liver and bone marrow
What allows for arteries and veins to get into the spleen?
trabeculae
What is white pulp of spleen?
collection of B and T cells
What is the red pulp of the spleen?
filled with blood
What are sinusoids of spleen?
contain mostly blood
What are pulp cords of spleen?
cellular components that contain large numbers marcophages and neutrophils
-large numbers of reticular cells and fibers
What is at the center of white pulp of spleen/
central artery
-may or may not have germinal center
What is the marginal zone of spleen?
lighter staining portion of the exterior of white pulp
What is the function of white pulp?
site of antigen presentation
-phagocytosis, macrophages, plasma cells, and helper t cells
What are splenic nodules?
enlarged germinal centers visible with naked eye
What are PALS?
periarteriolar lymphatic sheaths
-right around the central artery of the white pulp
-T cells
What are central arteries branches of?
the trabecular arteries
What do central arteries branch into?
penicillar arterioles
What do penicillar arterioles terminate into?
sheathed capillaries
What is open circulation of spleen?
when the penicillar arterioles dump blood right into the splenic cords
What is closed circulation of the spleen?
penicillar arterioles dump blood into the sinusoids
What are sheathed capillaries?
capillaries that do not have endothelial cells
-have macrophages that look at the blood
What makes up a majority of the spleen?
red pulp
75%
What are stave cells?
elongated, fusiform endothelial cells that are along the splenic sinusoids
-do not have intercellular junctions
What is the purpose of the sinuoids?
allow red blood cells to leave
What helps to ID and destroy old RBC?
the fact that they are not able to leave out of the stave cells
-tells the macrophages that it is time to be destroyed
What does MALT stand for?
muscosa-associated lymphoid tissue
Where is MALT located?
in gut tube, respiratory system, genitals, and urinary system
What is the function of MALT?
detect antigens and initiate response
What are tonsils?
epithelia lined collections of lymphoid nodules located in the oral and nasal cavities that provide immune surveillance of antigens entering the body through the mouth and nose
Where are pharyngeal tonsils? (adenoids)
on the back of nasopharynx
Where are palatine tonsils?
back of oral cavity (this is what gets removed when you think of them getting removed)
-between palatoglossal and palatopharyngeal arches
(anterior and posterior tonsilar pillars)
Where are lingual tonsils?
at the posterior 1/3 of tongue
What type of cells make up the palatine tonsils?
non-keratinized stratified squamous epithelium
Which surface of palatine tonsil does not have a capsule?
the surface that faces into oral cavity
What is the capsule that runs on the posterior of the palatine tonsil?
hemicapsule
What are tonsillar crypts?
spaces in palatine tonsils that allow the food being eaten to go in and be surveyed to make sure there is nothing pathogenic in it
What are dome areas of MALT?
connective tissue that projects into the lumen of thegut
-secrete IgA
What are M-cells?
have lots of microfolds that allow for increased surface area to make sure there is nothing bad in it
What is the appendix?
thing that sticks off cecum and contains a lot of lymphocytes (mostly B cells)
-herbivores use it to ferment bacteria
