EPITHELIUM (Lecture 4) Flashcards
5 main functions of the epithelial tissue
-protection (penis)
-secretion (sucking)
-transcellular transport (takes tons)
-absorption (additional)
-sensory detection (skills)
epithelial cells are attached basally to a ______ membrane
basal membrane
3 domains of the epithelial cells
apical
lateral
basal
domain that borders basement membrane and is related to underlying connective tissue
basal domain
domain that borders on the lumen
apical
domain that borders on neighboring cells
lateral domain
______ specializations of the plasma membrane often define the function of that epithelial cell
apical specialization (like if its cilia or microvilli)
function of microvilli
absorption
- extend into lumen to increase the SA for absorption
common areas for microvilli to be found
intestines and kidney tubules
cilia contain a core of _____
microtubules
what type of epithelial tissue is this
simple cuboidal
what type of epithelial tissue is this
pseudostratified columnar
characterized by nuclei located in at least two more-or-less distinct levels. But every cell rests on the basement membrane
type?
stratified squamous
type?
simple columnar
type?
simple columnar
what is this
microvilli
lateral interdigitations are abundant in what kind of cells
cells that are engaged in fluid transport (ex: intestines)
what is one thing lateral interdigitations do
increase lateral surface area
a surface layer that covers the cell membrane of many bacteria, epithelial cells or other cells.
glycocalyx
?
glycocalyx
3 parts of the junctional complex of the lateral interdigitation
- zonula occludens
- zonula adherens
- macula adherentes
zonula occludens AKA ___?___
TIGHT JUNCTION
zonula adherens AKA __?____
INTERMEDIATE JUNCTION
macula adherentes AKA ___?____
DESMOSOME (SPOT JUNCTION)
main function of zonula occludens (tight junction)
to form a protective barrier between epithelial cells
- Separates the luminal space from the intercellular space and the CT compartment
the ‘leakiness’ of the tight junction depends on
the number of ridges and grooves
main function of zonula adherens (intermediate junction)
cell to cell adhesion
main function of macula adherens (desmosomes)
cell to cell adhesion
in what types of cells would an abundance of gap junctions be found
in tissues that accomplish coordinated functions , cells that talk alot
(cardiac muscle, neurons)
specialized lateral domain that’s function is for exchange or signaling b/w adjacent cells
gap junctions “communicating junctions”
the basal domain is specialized for what
cell-to-ECM adhesion
the lateral domain is composed of _____ + _____
junctional complex + gap junctions
is the gap junction part of the junctional complex?
NO, the gap junction is part of the COMMUNICATING junction
What are the differences b/w the basal lamina and basement membrane
the basal lamina is made of 2 layers while the basement membrane is composed of 3 layers
the basement membrane seperates the epithelial tissue from ______
underlying connective tissue
what are the components of the basement membrane
basal lamina + reticular lamina
how do epithelial cells attach to the basal lamina?
vis spot welds (hemidesmosomes)
term for “1/2 a desmosome”
hemidesmosomes
part of the hemidesmosome that attach cell to the basal lamina and are associated with intermediate filaments
attachment plaques
associated w/ actin filaments and are important for mechanoreception
focal adhesions
type of epithelium that is tough and makes up most of the coverings/linings in the body
stratified epithelium (pic is non-keratinized)
toughest and makes up most of skin
kertatinized stratified epithelium
2 types of glands
endocrine : secrete hormones into blood or lymphatic vessels
exocrine: secrete into ducts
describe the characteristics of endocrine glands and cells
- they are ductless: no, lumen
- reverse polarity: polarized toward the basement membrane
- produce hormones
- secretion can be constitutive or regulated
Exocrine glands can be classified based on their _____ and type of _____
- structure (branching of the ducts)
- type of secretion
structure: simple = little or no branching, compound: multiple layers of
what does being avascular mean for epithelial tissue
it limits its size
purpose of microvilli
extend into the lumen to increase SA for absorption
found in intestines and kidneys
cross section of??
microvilli
microvilli are composed of _____ and ______
actin core + terminal web (also made of actin)
cilia have a core of _______ ?
microtubules, this allows for movement
name of this arrangement of cilia
9 triplets
name of this arrangement of cilia
9+2 arrangement
as basal bodies get extended into the cilium, they rearrange into ________
the 9+2 arrangement
basal bodies that develop from procentriole organizers are in the _______ arrangement
9 triplets
3 functions of the lateral domain
- forms a selective barrier
- adherence
- communication
what is the benefit of lateral interdigitations?
increase lateral SA which increases absorption!
another name for junctional complex
terminal bars
what is circled
junctional complex
the distance b/w adjacent cell membranes is spanned by ___________ that ‘link’ the cytoskeletons together
INTEGRAL MEMBRANE PROTEINS aka “linking proteins”
what are the components of the macula adherens (desmosomes “spot junction”)
attachment plaques
intermediate filaments
linking proteins
specialized lateral domain, “communicating junctions” “nexus”
gap junction
main function of gap junction
exchange or signaling b/w adjacent cells
part of the junctional complex that is associated w/ intermediate filaments
macula adherens (desmosome)
part of junctional complex associated w/ Actin
zonula adherens (intermediate junction)
does the basal domain also exhibit infoldings
yes, esp in places that do a lot of absorbing like kidney
whats this
focal adhesions (made of actin)
what are these
intermediate filaments
what is this
reticular lamina (secreted by connective tissue)
what this
basal lamina (darker)
what this
reticular lamina
these attach the cell to the basal lamina and are associated with intermediate filaments
attachment plaques
whats this
attachment plaque
whats this (pink circle)
linking proteins
type of glands that exhibit reverse polarity and therefore secrete basally
endocrine glands
type of glands that secrete apically
exocrine glands that secrete into ducts or lumen
2 types of secretion for exocrine glands
- serous (watery)
- mucous (mucousy)
What is this arrangement found in cilia
9+2 arrangement of cilium
what is this arrangement found in cilia
9 triplets found in basal body
what are the two types of gland tissue
- PARENCHYMA (epithelial)
—> working cells - STROMA (CT)
—-> supporting tissue
