Epithelial Tissue Flashcards
Types of Epithelia
surface
glandular
Surface epithelia
selective barrier b/t lumen and tissues
covers external/internal surfaces
lines tubes
Glandular epithelia
comprise functional components of many solid organs
secrete glandular products
form ducts to carry secretions
generate gametes/foster maturation
General Characteristics
highly cellular (little/no ECM)
anchor to basement membrane
polarity (apical/lateral/basal domains)
numerous junctions
avascular (lacks blood or lymph vessels)
intermediate filaments = keratin
Basement membrane
functions
structural support
physical barrier
metabolite diffusion
orient direction of growth
Basement Membrane
structure
lamina lucida = electron lucent
@ just beneath cells
lamina densa= electron dense
@ beneath lucida
lamina fibroreticularis
@ beneath densa
Lamina lucida
compostion
glycoproteins/laminins
Lamina densa
composition
collagen IV
sulfated GAGs
collagen IV primary protein of BM
forms mesh
Lamina fibroreticularis
composition
collagen III (reticulin)
collagen VII (anchoring fibrils)
small collagen I
connect/anchor densa to connective tissue
basal lamina
lucida + densa only
basal lamina
function
flexible support
molecular filter
col IV and sulfated GAG’s filter
basement membrane
components
basal lamina + lamina fibroreticularis
classification of epithelia
shape
number of layers
specializations
number of layers subgroups
simple - 1 layer
stratified- 2+
pseudostratified- 1 layer but look stratified
simple epithelia
1 layer
all cells touch BM
good for diffusion, absorption, lubrication, secretion
stratified epithelia
2+ layers
only basalmost layer touches
structural support, barriers, resist abrasion
largest ducts/conduits
stem cells located in basal layer
pseudostratified
1 layer
all cells touch but nuclei at diff levels
shape of cells
luminal/superficial layer
squamous
cuboidal
columnar
transitional
specializations
individual cells
cilia, stereocilia, microvilli
specializations
superficial layer whole
goblet cells
keratinization
types of epithelia
simple squamous
simple cuboidal
simple columnar
pseduostratified columnar
stratified squamous
stratified cuboidal
stratified columnar
transitional
simple squamous
lens shape, sunny side up eggs
diffusion, lubrication
easy tear
simple cuboidal
squarish w/large central round nucleus
small ducts, secretions, absorption
simple columnar
tall rectangles
mainly secretion and absorption so GI tract
pseduostratified columnar
almost always ciliated, often have goblet, maybe stereocilia
common in trachea, bronchial tree, epididymis, ductus deferens
stratified squamous
maybe keratinized or not
resist abrasions and all purpose barrier
stratified cuboidal
rare
decent barriers
forms ducts
stratified columnar
more rare
basal layer always cuboidal
barriers and largest ducts
transitional
4+ layers
rounded like domes when relaxed
stretched when thinner
urinary tract and uterus
keritanization
whole apical layer
basal/middle cells = keratin IF
goblet cells
whole apical layers
modified columnar cells
secrete mucus
pas positive bc mucus carb rich
cilia
individual cell
most common special
hairlike, easy to see LM
types of cilia
motile
primary
nodal
motile cilia
distinct hair like
active transport
back and forth move or wave
types of motile cilia
dynein
basal body
striated rootlet
dynein
motor proteins
temporary cross bridges w/adj microtubules
basal body
modified centriole 9x3 + 0
stabilizes microtubules, secrete tubulin
dark staining band in LM
striated rootlet
anchors cilium into cytoplasm
primary cilia
only 1 per cell
sensory antenna
essential for controlling division and normal tissue morphogenesis
non motile bc no motor proteins in every cell of body
9x2 + 0 microtubule array
nodal cilia
early stages embryos (primitive node bilaminar disk)
essential in developing left-right asymmetry bc gradient of morphogens from movement
9x2 + 0 arroay with motor proteins
Kartagener’s Syndrome
definition
primary ciliary dyskinesia
lack motor proteins
Kartagener’s Syndrome
symptoms
bronchiectasis
chronic rhinosinusitis
situs inversus
lady bug missing antennas so look like 8
microvilli
short blur along luminal surface
inc apical surface for absorption
nonmotile, most epithelial cells
microvilli
structure
core of 20-30 actin filaments
anchored in terminal web of cell cortex with myosin
microvilli
myosin
part of terminal web
contract so that bases come together and ends separate
stereocilia
NOT CILIA
very long microtubules instead
stereocilia
absorption (male reprod)
mechanoreceptors (inner ear)
nonmotile
no myosin
