Lymphoid tissue Flashcards
where are lymphocytes
blood
interstitial CT
lymphoid organs
lymphoid nodule description
spherical accumulation of B cells
solitary or aggregates
may have germinal centers
germinal centers
pal centers in activated nodules
where is MALT
GALT
respiratory tract
genitourinary tract
lymphoid organs
tonsils
lymph nodse
spleen
thymus
palatine tonsils
stratified squamous epithelium
deep crypts
pharyngeal tonsils
pseudo stratified columnar epithelium
glands and lymphoid tissue
lingual tonsils
stratified squamous epithelium
one crypt per tonsil
cortical blood thymus barrier
desmosomes between thymic epithelial cells to separate the thymus cortex from the blood
hassal’s corpuscles
in medulla- concentric layers of epithelial reticular cells and keratin
outer cortex of lymph node contains
b cells
inner cortex of lymph node contains
t cells
medullary cords of lymph node ontains
stacks of cells (b cells, plasma cells, macrophages)
medullary sinuses of lymph node
spaces between cords surrounded by macrophages, reticular cells, and reticular fibers
high endothelial venuoles
bring circulating lymphocytes to the medulla
lined by cuboidal epithelium
receptors attract lymphocytes
spleen white pulp
periarterial lymphatic sheath (PALS)- t cells around the arteries and arterioles
lymphatic nodules of T cells along PALS
purple colored
spleen red pulp
reticular fibers and cells surround sinusoidal capillaries
splenic cords- cells
splenic sinuses- sinusoidal capillaries
red colored
marginal zone of spleen
between red and white pulp with macrophages
lymph node reactive hyperplasia
enlarged lymph nodes due to infection
follicular lymph node hyperplasia
humoral response
b cell proliferation
parafollicular hyperplasia
t cell activation
sinus dilation in lymph node
increased macrophage activity
hodgkin’s lymphoma
characterized by reed-sternberg cells- tumor cells from activated t cells
non-hodgkin’s lymphoma
tumor cells from b cells
