Epithelium Flashcards
apical domain
faces the lumen or external environment
basal domain
faces the basement membrane
basolateral domain
lateral and basal domain together
function of microvilli
increase surface area for absorption
what is microvilli made of and what attaches actin filaments with eachother
actin filament bundles, linked by proteins villin and fimbrin
what attaches lateral arm of microvilli to plasma membrane
myosin 1 and calmodulin
what connects microvilli to cytoplasm
myosin II and spectrin
myosin II is a contractile protein
causes contraction to terminal web
what will be impact on microvilli after contraction of myosin II
epical diameter of cell is reduced, cell becomes shorter, causes microvilli to move adduction and abduction, advantage is creating surface area for nutrients
stereocilia
extremely long microvilli
where is stereocilia found
found in epididymis, inner ear,
what is cilia made of
microtubules or the axoneme
centrioles form basal body during development
three types of cilia
motile which beat, primary with no active movement, and nodal with slight rotational movement in the embryo
basal body is a MTOC
microtubule organizing center
what is motile cilia form in the respiratory tract
muco-cilary unit
what does muco-cilary unit do
sweeps mucous and trapped material toward oropharynx
motile cilia in the oviduct
beats fluid towards the uterus
motile cilia is covered by
cilia membrane, transmembrane proteins are different from plasma membrane
inside motile cilia is
anoxneme, microtubules are made of tubulin subunits
microtubules are arranged in specific matter in motile cilia
9 + 2 arrangement= 9 doublets of circularly arranged peripheral microtubules, surround 2 central microtubules.
what are peripheral microtubules made of in motile cilia
alpha and beta tubulin subunit
2 alpha dynein ends are only in what
alpha microtubules
what is nexin
an elastic protein that links to next doublet
what is radial spoke
control of dynein arm by relaying signals
basal body holds triplets, does not extend past basal body
there are triplets
each doublet exhibits a pair of arms that contain
dynein and ATPase
Arm extends from A microtubule, to form temporary cross bridges
with B microtubules of the adjacent doublet
primary ciliary dyskineasiaor immotile cilia syndrome (ICS)
autosomal recessive disease, characterized be abnormal ciliary motion, and imapaired muco-ciliary clearance
kartagener syndrome
dynein arms are absent in the cilia, leads to abnormal ciliary function
kartagener syndrome
characterized by triad of situs inversus, chronic sinusitis, and bronchiectasis
two disorders affecting the muco-ciliary unit
Primary Ciliary Dyskinesiaor Immotile cilia syndrome, and kartagener syndrome
primary cilia
Function as a signal receptor, axoneme is 9+0 microtubule
nodal cilia
Make rotational movement, 9+0 microtubules
nodal cilia
concentrated in area of the primitive node
basolateral surface specialization
lateral folds and basal folds
lateral surface shows a tortuous bounday
due to infoldings of cells with neighbors, this increases lateral surface
where are lateral folds found
epithelium of intestines and kidney tubules
lateral folds are prominent in cells that transport fluid rapidly
basal folds have characteristics of what
fluid transporting cells
example is proximal and distal tubules of kidney, and salivary gland ducts
mitochondria provide energy for functioning basal folds and active transport
the presence of the basal folds and mitochondria orientation together form
striated appearance at basal aspect
example Striated ducts of salivary gland
junctional complex has 3 components
occluding junctions, anchoring junctions, communicating junctions
cell to cell adhesions are called what in a LM
terminal bar
