Flashcards in Epithelial Tissue Deck (27):
Describe the functions of epithelia
line cavities and cover surfaces, separate 2 distinct domains while interacting with the contents of each domain
Describe the characteristics of epithelial cells
tightly packed together, form avascular sheets, attached to a basement membrane, sit on underlying connective tissue, have polarity (apical and basal regions)
Name the two kinds of apical surface modifications
Function of microvilli?
to increase surface area of hte cell
Microvilli have what kind of filaments to give them structure and anchor?
Function of cilia?
move fluid and particles along epithelial surfaces
Cilia have what to give them structure?
What anchors cilium to the cytoskeleton?
3 kinds of lateral surface modifications?
occluding junctions, anchoring junctions, communicating junctions
Describe occluding junctions
tight junctions, seal membranes together
Occluding junctions are formed by what two transmembrane proteins
Describe anchoring junctions
zonula adherens provide lateral adhesion (hold cells together); macula adherens = desmosome, spotlike junction
Zonula adherens consist of what 2 proteins? that link to?
Cadherins, integrins; actin filaments of cytoskeleton
Describe communicating junctions?
Gap junctions permit passage of molecules
gap junctions are made of what protein family?
Connexin proteins - make connexons (pores that can be open or closed)
Name the 2 areas of the basement membrane
Basal lamina (directly below epithelial cells); reticular lamina below basal lamina
Name the 2 anchoring junctions on the basal surface
Hemidesmosome and focal adhesions
Describe focal adhesions on the basal surface
anchor the cell's internal actin to basal lamina; use integrins (transmembrane proteins) to detect/transduce signals
Transitional epithelium has what special cells on the apical surface
dome cells (or umbrella cells)
Simple squamous function
thin barrier for exchange, frictionless movement of fluids and/or organs
Simple cuboidal function
line a conduit, can absorb and/or secrete materials
Simple columnar function
absorption and/or secretion
Stratified squamous keratinized function
protection of dry areas
Stratified squamous nonkeratinized function
protection of moist areas
Stratified columnar function
Pseudostratified columnar function
secretion, conduit in resp. tract and epididymis; move mucus, absorption,