Epithelium Flashcards
lining of surfaces of the body cavities; glandular secretion
epithelial tissue
where does the epithelium rest?
basal lamina
a thin continuous supporting layer that separates the epithelial tissue from the underlying connective tissue
basal lamina
what are the basal lamina composed of
type 4 collagen, laminin, and proteoglycans
single layer of flattened cells usually joined by intercellular junctions and resting on basement membranes
simple squamous epithelium
provides protection, forms conduits for gland ducts, and may be specialized for active secretion and absorption
simple cuboidal epithelium
mainly found in sites engaged in protection of wet surfaces, nutrient absorption, and secretion
simple columnar epithelium
poorly suited for absorption and secretion by virtue of their thickness; some are moderately permeable to water and other small molecules; two or more layers of cells
stratified epithelium
can be seen in epidermis
stratified squamous keratinized
widely distributed in the mouth, esophagus, larynx, vagina, and anal canal
stratified squamous non-keratinized
widely distributed in the mouth, esophagus, larynx, vagina, and anal canal
stratified squamous non-keratinized
examples includes sweat glands and developing ovarian follicles
stratified cuboidal
example includes conjunctiva
stratified columnar
found only in the urethelium with special features to make it waterproof and expansile
transitional epithelium
hairlike organelles that are easily observed in light microscopy
cilia
most important type of cilia
motile cilia
what happens when there is a defective cilia?
kartagener syndrome
extremely long microvili which is usually found in singly or small numbers
stereo cilia
it increases the surface area for absorption by 30x
microvilli
disorder of the small intestine in which one of the first pathologic changes is loss of the microvilli brush border of the absorptive cells
celiac disease
celiac disease is triggered by what?
wheat, barley, and rye
enumerate the histologic triad of celiac disease
appearance of intraepithelial lymphocytosis; inflammation, villous atrophy
modified columnar epithelial cells that synthesize and secrete mucus
goblet cells
ductless and release products called hormones directly into the bloodstream
endocrine glands
connect to the surface by ducts which take the secretions to the surface or lumen
exocrine glands
no destruction after secretion
merocrine
it involves the cell filling with secretory products; total destruction
holocrine
part of the cell is excreted out together with the secretory products of the cell; partial destruction
apocrine
main protein components of tight junction
claudins, occludins, tricellulin
site of tight junction
luminal end of lateral cell membrane
main function of tight junction
control of paracellular diffusion; prevents exchange of intrinsic proteins
main protein component of adhering belt
classic catherine, catenins
site of adhering belt
lateral plasma membrane; immediately deep to tight junction
main function of adhering belt
link cytoskeletons of adjacent cells to form strong cohesive epithelium
main protein component of desmosome
cadherins
site of desmosomes
lateral plasma membrane
main function of desmosome
link cytoskeletons of adjacent cells to form strong cohesive epithelium
main components of hemidesmosome
integrins, laminins of basement membrane
site of hemidesmosome
basal plasma membrane
main function of hemidesmosome
link cells to underlying basement membrane
main components of gap junctions
connexins
site of gap junctions
lateral plasma membrane
main function of gap junctions
passage of ions and small molecules between cells; intercellular signaling
