Epithelium 1 Flashcards
Where would you find epithelial cells in the body?
external and internal surfaces and lines body tubes (ex. blood vessels, GI tract, and respiratory passageways)
What are the three epithelial cell domains?
apical, lateral, basal
Does epithelia have blood supply?
No, they are avascular with the exception of stra vascularis
What are the characteristics used to classify epithelia?
1) number of cell layers
2) cell shape of the superficial layer
3) presence of specializations of plasma membrane (ie keratin)
What are the characteristics of simple epithelia?
single layer
What are the characteristics of stratified epithelia?
multiple layers
What are the characteristics of squamous epithelia?
flattened, scale-like
What are the characteristics of cuboidal epithelia?
height is about equal to width
What are the characteristics of columnar epithelia?
much taller than they are wide
What are the characteristics of pseudostratified epthelia?
- only one layer of cells
- all cells have connections to the basement membrane
- they appear to be stacked on top of each other.
Be careful with this, it gives the false impression that it is stratified, but it is only one layer (hence “pseudo”stratified)
What are the functions of simple squamous epithelia?
blood- brain barrier
filtration
exchange of nutrients
What are some locations of simple squamous epithelia?
endothelium (lining of blood vessels)
mesothelium (lining of abdominal cavity)
alveolus (lining in the lungs)
What are the functions of simple cuboidal epithelia?
absorption
secretion
barrier
conduit
Where can you find simple cuboidal epithelia?
thyroid follicles
renal tubules
ducts of glands
What the two types of simple columnar epithelia?
non-ciliated and ciliated
Where can you find ciliated simple columnar epithelia?
uterine tube
What are the functions of ciliated simple columnar epithelia?
absorption
secretion
barrier
Where can you find non-ciliated simple columnar epithelia?
stomach, intestines
Where can you find pseudostratified columnar epithelia?
trachea, bronchi, ducts of male reproductive system (actually sterocilia)
What are the functions of psuedostraified columnar epithelia?
secretion
absorption
barrier
transport
What are the two types of stratified squamous epithelia?
non-keratinized and keratinized
Where can you find non-keratinized stratified squamous epithelia?
esophagus
distal anal canal
vagina
What are the functions of non-keratinized stratified squamous epithelia?
barrier and protection
Where can you find keratinized stratified squamous epithelia?
epidermis
What are the funcitons of keratinized stratified squamous epithelia?
barrier and protection
What is the difference between non-keratinized and keratinized squamour stratified epithelia?
non-keratinized are live cells; keratinized cells are dead (easily slough off) and they are packed with keratin
What are keratin pearls?
squamous cell carcinoma
What is the special feature of transitional epithelia that is much different than all the other epithelia?
they can be stretched out (ie allows for bladder to expand)
Where can you find transitional epithelia?
ureters, urinary bladder, urethra
What are the functions of transitional epithelia?
barrier, protection, distention
A patient has chronic gastric acid reflux, what type of epithelia would you suspect to find in the distal end of the esophagus?
it is normally stratified squamous, non-keratinized, but in this patient the epithelium will transform itself to become more like intestinal epithelium with goblet cells. This is a protective mechanism, but unfortunately is also pre-cancerous
What are some specializations of the plasmalemma?
cilia
flagella
microvilli
stereocilia
What are the three types of cilia?
motile, primary aka moncilium (nonmotile), nodal (motile)
Describe the structure of motile cilium.
9 doublets of microtubules
dynein arms extend from the microtubules
two individual microtubules in the center
Describe the structure of primary or monocilium (nonmotile)
also 9 doublets, but do not have central two microtubules.
What are the functions of primary, monocilium?
- chemosensors, osmoreceptors, and mechanoreceptors
- mediate light, taste, and sound perception
- also have important role in normal tissue morphogenesis
What happens when there’s a mutation in either polycystin 1 or 2 genes?
the orientation of the spindle will change leading to cystic tubular expansion and cysts form in result
Where are nodal cilia located?
primitive node
Describe the structure of nodal cilia.
have the structure of noncilium (9x2), but it is motile and does contain dyenin (ATP production)
Nodia cilia is important for which stage of embryological development?
right and left axis formation
the nodal cilia spins from right to left, directing fluid flow for axis formation
Describe the structure of microvilli.
- extension of plasma membrane at apical domain of the cell
- actin microfilaments cross-linked by variety of cytoskeletal proteins
What is the function of microvilli in the intestine?
increase surface area
What is striated/ brush border?
well-developed microvilli
What stain can be used to identify brush border area? What is the cell coat?
PAS, glycocalyx
What are stereocilia?
elongated microvilli
A patient presents with chronic sinusitis, bronchiectasis, and situs inversus, what is the diagnosis?
Kartagenar Syndrome
the triad of symptoms are hallmark of this diagnosis
