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76 Cards in this Set

  • Front
  • Back
what are the 3 major functions of epithelial cells?
protection, absorption, secretion
what are the 3 surfaces of epithelial cells?
apical (free), lateral, basal
which two epithelial surfaces are often grouped as one?
basal and lateral (basolateral)
what are the 3 types of apical processes found in epithelium?
microvilli, cilia, stereocilia
which, cilia or microvilli, are known as the 'brush border'?
microvilli bc they cannot be seen with a LM
what is the main role of microvilli?
absorption
which cytoskeletal element provides support for microvilli?
actin
what is the name for the web of cytoskeleton that anchors microvilli?
terminal web
what causes microvilli to split apart, increasing absorption?
contraction of terminal web (actin filaments)
what is the main role of cilia?
motility
where are the 2 primary locations of cilia in the body?
respiratory tract, uterine tubes
which cytoskeletal element provides support for cilia?
microtubules
what is the name for the central core of cilia?
axoneme
in which pattern of cytoskeleton are cilia constructed?
9+2 microtubule pattern ( 2 central MTs surrounded by 9 pairs)
cilia are anchored to epithelial cells via which structures?
basal bodies
basal bodies are modifies version of what cellular component?
centrioles
are stereocilia longer or shorter than microvilli?
longer
true or false. Sterocilia are motile, like cilia.
false, they are wrongly names and are not motile.
what are the 3 types of junctions found on lateral surfacs?
occluding junctions, adhering junctions, and communicating junctions
what is another name for tight junctions?
ZO (zona occludens)
which of the lateral junctions are found closest to the apical surface?
tight junctions
what is the primary function of the tight junctions?
to seal off intercellular space from exterior/lumen
which of the lateral junctions creates protein 'rafts', sealing them off from other surfaces?
tight junctions
binding of what forms the tight junctions?
transmembrane proteins
what are the 2 forms of lateral adhering junctions?
zonula adherens and desmosomes
what are the 3 components of zonulae adherins?
transmembrane proteins, anchor proteins, cytoskeleton
what is the class of transmembrane proteins that provide support in zonulae adherins? What is the more specific kind of protein used here?
Cell Adhesion Molecules (CAMs); cadherins
which proteins form the anchor for zonulae adherins?
catenin
zonulae adherins are eventually anchored to which kind of cytoskeleton in the cells?
actin
which of the lateral adhering junctions does not form a complete ring around the epithelial cells?
desmosomes
by what are desmosomes anchored to cell membrane?
attachment plaques
what transmembrane proteins are present in desmosomes?
cadherins
to which element of the cytoskeleton are desmosomes attached?
intermediate filaments
which are stronger junctions, zonulae adherins or desmosomes?
desmosomes
what is the name for the communicating lateral junctions?
gap junctions
what are the larger and smaller units of gap junctions? How many are present per cell?
connexins and connexons; six connexins form 1 connexon
which lateral junctions form the junctional complex?
tight junctions, zonulae adherins, desmosomes
what is the name for the 'bar' that can be seen under the microscopr, representing the 3 uppermost lateral junctions?
terminal bar
why does the basement membrane stain PAS positive?
because it has a high concentration of carbohydrate molecules
what are the major components of the basement membrane?
proteoglycans, type IV collagen, fibronectin, laminin
what are the 3 layers of the basement membrane?
lamina lucida, lamina densa, lamina fibroreticularis
which two types of adhesion junctions anchor epithelial cells to basement membrane?
hemidesmosomes and focal adhesions
which basal junction binds to intermediate filaments?
hemidesmosomes
which transmembrane proteins are involved in both hemidesmosomes and focal adhesions?
integrins
which element of the cytoskeleton do focal adhesions use to anchor epithelial cells to the basement membrane?
actin
what are two diseases that result from the disruption of the basement membrane?
epidermolysis bullosa and bullous pemphigoid
what are the 3 major classifications of surface (non-gland) epithelia?
number of cell layers, shape of cells, presence of surface specializations
what are the 3 shapes of epithelial cells?
squamous, cuboidal, columnar
what are pseudostratified epithelial cells?
cells that appear to be in layers but are really all anchored at basement membrane in 1 layer. Not all cells reach apical surface.
what is the name for the epithelial cells that are found in urinary tract and have the capacity to stretch?
urothelium
which two surface specializations on epithelia are often mentioned in the naming of the cells?
keratin and cilia
where is endothelium found?
at the interior of blood vessels
where is mesothelium found?
lining serous body cavities
which 2 characteristics are used to classify gladular epithelium?
number of cells, structure
which class of glands may have ducts?
exocrine
what are the 3 types of ducts present in exocrine glands?
merocrine, apocrine, holocrine
which type of gland releases secretory vesicles with plasma membranes? Which releases vesicles without membranes?
apocrine; merocrine
which type of gland self-destructs when it releases its secretions?
holocrine
what is the classic example of a unicellular gland?
Goblet cell
what is the name for glands with more than 1 duct?
compound
what are the 3 major gland shapes?
tubular, acinar, tubuloacinar
what are the 2 basic forms of endocrine glands?
cords or follicles
where is epithelial vasculature located?
connective tissue
what covers microvilli? Cilia?
plasma membrane for both
which motor protein allows cilia to move?
dynein
what is the name for epithelium that has a sensory function (i.e. tongue)?
neuroepithelium
what is the name for the type of epithelium cell that contracts?
myoepithelium
to which layer of the basement membrane are hemidesmosomes and focal adhesions bound?
lamina densa
where could you find simple cuboidal epithelium? ciliated simple columnar? simple columnar with microvilli?
kidney tubules; respiratory tract; small intestine
where can you find non-keratinized stratified squamous epithelium?
esophagus
where might one find keratinized stratified squamous epithelium?
skin
where might one find stratified cuboidal epithelium?
sweat ducts
where are the rare stratified columnar epithelia found?
in transition zones like in the anus.
where will you normally find pseudostratified columnar epithelium? do they normally have any surface specializations?
respiratory tract; cilia
can cilia be present in stratified epithelium?
no
what is an example of apocrine gland? holocrine?
breast milk (mammary glands); sebaceous glands (hair follicles)