MCM Final - Epithelium Flashcards
endothelium
blood and lymph vessels
epithelium
tissues that line and cover body surfaces
avascular - no blood vessels
show cell polarity
progenitor cells present (dynamic)
mesothelium
lines serous cavities
ex./peritnoeum
glands
epithelial invaginations
simple epithelium
one cell layer
stratified epithelium
two or more cell layers
pseudostartified
all cells touch touch basal membrane, but not all reach surface
look stratified, but not
squamous epithelium
flattened cells
cuboidal epithelium
square cells
columnar epithelium
tall cells - 2x tall as wide
microvilli
specialization of the epithelium
increase absorptive area
actin filament core
-interact with terminal web in the cytoplasm
sterocilia
really long microvilli
striate border
microvilli
also brush border
cilia
specialization in the apical portion of epithelium
terminal web
network of microfilaments and intermediate filaments that support the apical structure microvilli
zona occludens
tight junctions
permeability seal and also establish functional domains
-separation of membrane portions
goblet cell
specialization in epithelium
secretes mucus
keratinization
aka cornified
specialization of epithelium
also referred to as “dry” if keratinized (as opposed to wet)
parakeratinized
specialized epithelial in oral cavity
cells are partially keratinized
transitional epithelium
doesn’t follow normal classification system of epithelium
has the ability to stretch
-dome cells (umbrella cells) can stretch
ex./ urinary bladder
epithelium in ducts?
stratified cuboidal
zonula adherens
lateral epithelial structure
responsible for strength of cellular attachments
-resistance to shearing stress
utilizes E-cadherin
dense plaques
in zonula adherens
myosin, tropomyosin, alpha-actinin, vinculin
E-cadherin
utilized mainly in the zonula adherens but also present in the zona occluden
extracellular protein
terminal bar
combination of zona occludens and zona adherens
gap junctions
integral membrane proteins that allow for exchange between cells
formed from 6 connexin subunits (12 total - one on each cell’s membrane)
opening of pore due to adjacent connexins aligning
connexin
subunit of gap junction
6 together form pore
desmosome
links cell to cell
“spot weld” between cells - strong attachment
tonofilaments attach to cadherins that extend into extracellularly
desmoglein and desmocollin
tonofilaments
tension fibers
in desmosomes - intermediate filaments that anchor the macula adherens
the two cadherins in desmosomes?
desmoglein and desmocollin
what cell layer has lots of desmosomes?
stratum spinosum layer of skin
-has “spines” which are points of desmosome attachment
fascia adherens
similar to zonula adherens
form broad faced adhesion plate
- in intercalated disc of cardiac muscle - adherens junctions stretch across terminal plate of cardiac muscle cell
nexus
gap junction
basement membrane - two parts?
basal lamina and reticular lamina
reticular lamina
layer of underlying connective tissue in basement membrane
basal lamina
immediately underlying cells in the basement membrane
two layers of basal lamina?
lamina rara and lamina densa
lamina rara
aka lamida lucida
laminin, entactin, and other PGs
lamina densa
layer of basal lamina
collage IV, fibronectin, and perlecan
collagen VII
anchoring fibrils that attach collagen to the lamina densa of the basal lamina
hemidesmosome
connects cell to ECM
located on the basal cell surface of epithelium
-connect epithelium to underlying basement membrane
