Lymphoid II Flashcards
lymph nodes
line of defense against antigens which penetrate the epithelium and MALT and gain access to underlying connective tissue
components of lymph nodes
dense connective tissue capsule, reticular fibers, macrophages, reticular cells
afferent lymphatics
pierce the outer connective tissue capsule and deposit lymph in the subcapsular sinus
subcapsular sinus
continuous with cortical and medullary sinus, where lymph enters
hilum
location of the draining efferent lymph
lympathic sinuses are line with ____ _____ that permits cells and antigens to enter the node
discontinuous endothelium
nodules are found in what region of the lymph nodes?
outer region of the cortex
paracortex
devoid of nodules and is T cell rich (thymus dependent zone)
high endothelial venules
in the paracortex, allows circulating lymphocytes to enter the lymph node
selectins
allow lymphocytes to home in on the lymph nodes and crawl through the walls
medullary cords
loose CT (containing reticular fibers), highly cellular
medullary sinuses
venous channel running between cords, distontinuous endothelium, traversed by reticular fibers
paracortical reaction
during a viral reaction, more selectins are expressed resulting in more lymphocytes adn swelling of the paracortical region
Hodgkin lymphoma
excess proliferation of lymphocyttes with Ree-sternberg cells
Reed-Sternberg cells
large cells with bilobed nucleus (owl eye appearance)
the spleen is covered by…
a squamous epithelium (mesothelium) and underlying is a thick connective tissue capsule
trabecular beams
continuous with the capsule, penetrate the spleen
Does the spleen have a cortex and a medulla
NO
periarterial lymphoid sheath
of the white pulp, contains both nodular and diffuse tissue and surrounds central arteries
Are there reticular fibers in the vessels of the spleen
NO (except in the marginal zone)
marginal zone
region between the red and white pulp, receives blood from the central arteries and promotes antigen interactions
red pulp
containts cords and sinuses, filters red blood cells
terminal sheathed capillaries empth into…
the meshwork of the red pulp cords
filtrations slits
holes in the endoletial venules of the sinuses that filter out mishapen red blood cells
