Epithelium I Flashcards
What are the three types of cells layers?
- simple
- stratified
- Pseudostratified
What is the defining characteristic of the pseudostratified cell layer?
One cell layer, with all cells stemming from the basement membrane
What defines a stratified cell layer?
2 or more strata; only the cells of the deepest layer reside on the basement membrane
Are cell layers vascular or avascular? What is the exception to this? Where is this cell type found?
Avascular–dependent on ECM
Stria vascularis in the cochlea is the exception
What are the three key characteristics that are used to classify cell epithelia?
- Number of cell layers
- cell shape in superficial layer
- Presence of specializations
What are the three types of simple epithelia?
- Squamous
- cuboidal
- columnar
What are the four types of stratified epithelia?
- squamous nonkeratinied
- cuboidal
- squamous keratinized
- columnar
What is the defining characteristic of transitional epithelia?
relaxed (not flat)
Distended (flattened)
Where is transitional epithelium found?
Urinary bladder
What type of epitheliuum is in blood vessels?
Simple Squamous
What are the three functions of simple squamous epithelia?
- Blood brain barrier
- Filtration
- Exchange
What type of epithelium is in the abdominal cavity (mesothelium)?
Simple squamous
What type of epithelia is in alveoli?
Simple squamous
What established the blood-brain barrier?
Tight connections between the squamous epithelia
What type of epithelium would be found in thyroid folliciles?
Simple cuboidal
What type of epithelium would be found in rental tubules?
Simple cuboidal
What type of epithelium would be found in the ducts of glands?
Simple cuboidal
What are the four functions of simple cuboidal?
- Absorption
- Secretion
- Barrier
- Conduit
What type of epithelium would be found in the stomach?
Nonciliated Simple columnar
What type of epithelium would be found in the intestines?
Nonciliated simple columnar
What type of epithelium would be found in uterine tubes?
Ciliated simple columnar
What are the three functions of simple columnar epithelium?
Absorption
Secretion
Barrier
What is the function of the cilia of the simple columnar cells of the uteruis?
Help oocyte move
What type of epithelium would be found in the trachea?
ciliated Pseudostratified
What type of epithelium would be found in the bronchi?
ciliated Pseudostratified
What type of epithelium would be found in ducts of the male reproductive system?
Pseudostratified with stereocilia
What are the four functions of ciliated pseudostratified,
Secretion
Absorption
Barrier
Transport
What is the telltale sign that you are looking at a slide from the trachea?
THICK basement membrane
Where type of epithelia are “goblets” found?
Pseudostratified
What type of epithelium would you find in the esophagus?
Non-keratinized stratified squamous
What type of epithelium would you find in the distal anal canal?
Non-keratinized stratified squamous
What type of epithelium would you find in vagina?
Non-keratinized stratified squamous
What type of epithelium would you find in Epidermis?
Keratinized stratified squamous
What are the functions of stratified squamous epithelium?
Barrier
Protection
Keratinized epithelium have kertatinized dead cells at the top of the epithelia. What is the advantage of this?
Extra protection/barrier
Looking at a sample of keratinized epithelial cells, you see large, eosinophilic keratin deposits that appear as whorled “pearls”. What is your diagnosis?
Squamous cell carcinoma
Stratified cuboidal epithelia are not common. Where is one place you would see this?
When cells are undergoing change from one type of epithelium to another
What is the other name for transitional epithelium?
Urothelium
Where are the three places that transitional epithelium is found?
Ureters
Urinary bladder
Urethra
What are the three functions of the transitional epithelium?
Barrier
Protection
Distension
What is the key characteristic to look for when attempting to determine if a transitional cell is distended or not?
If the top cells are flat or dome shaped
Dome = not distended
How do you grade the type/severity of transitional cell carcinoma?
How deep it goes from the epithelium
What is metaplasia?
The process of epithelium changing from one type to another
Normally the trachea has pseudostratified columnar epithelium with cili. What happens when there is a chronic insult to this layer of cells?
Undergoes metaplasia, changes to stratified squamous epithelium, and loses the cilia
What is the significance of losing cilia in the trachea due to smoking and metaplastic changes of the epithelium?
Cannot clear mucus
Under normal conditions, the distal esophagus has a stratified squamous epithelium, but undergoes metaplasia if it is exposed to a chronic insult, such as acidic stomach secretions in GERD. What type of epithelium will it change into? Is this cancerous?
Change to intestinal-like mucus secreting cells with goblets.
This is precancerous
What are the four major types of specializations that the plasmalemma can have in epithelium?
Cilia
Flagella
Microvilli
Stereocilia (sterovilli)
What are the three types of cilia?
- motile
- primary (monocilum)
- nodal
True or false: the cilia in the primitive node (nodal cilia) are motile
True
What are the three defining characteristics of motile cilium, when viewing it from a transverse cross-section (the upper part)?
- Nine sets of doublet microtubules arranged in a circle
- Dyenin ATPases with the triplets
- a single microtubule doublet in the center
The basal body of the motile cilium has what type of microtubular array?
9x3
What is the microtubular arragement of primary (non-motile) cilia?
9x2 arrays all the way through
What are the three functions of primary cilia?
- Chemoreceptors
- Osmoreceptors
- mechanoreceptors
What type of cilia form chemoreceptors?
primary (non-motile) cilia
What type of cilia form osmoreceptors?
primary (non-motile) cilia
What type of cilia form mechanoreceptors?
primary (non-motile) cilia
What type of cilia play a pivitol role in the formation of the kidney tubules?
Primary (non-motile) cilia
A mutation in polycistin 1 or 2 results in the development of what? What is the specific change in the cell that causes this?
Polycystic kidney tubules due to improper orientation of the mitotic spindle
Nodal cilia have what type of microtubule arrangement? What is the difference between nodal cilia and primary cilia?
9x2
Nodal cilia appear to have the same microtubular structure as primary cilia. What is the difference between nodal cilia and primary cilia?
Nodal are motile
What do nodal cilia help in the development of? A defect in this process leads to what condition?
Left/right axis
Situs inversus
Microvillia are an extansion of what structure?
Plasma membrane
What type of filaments are found within microvilia?
Actin
What do the actin filaments in microvilli form at the base of the structure?
Cross link actin of other microvilli to form the terminal web
The actin filaments within microvilli are crosslinked by four actin-binding proteins. What are their names?
Villin
Espin
Fimbrin
Myosin I
What is the actin binding protein that is found at the tip of the microvilli?
Villin
What is the actin binding protein that crosslinks that actin filaments in the terminal web? Action of this protein causes what?
Myosin II
Contraction, spreading the microvilli apart
Key distinction!!– what is the structural difference between microvillia and cilia (what makes up each ones’ structure?)
Cilia have microtubules in their structure
Microvillia have actin
Brush borders are filled with microvilli or cilia?
Microvilli
What type of stain would you use to highlight a brush border (tricky)?
PAS–there is a carb border at the top called the glycocalyx
Looking at a brush border epithelium that is stained with PAS, you see a huge deposit of stain in an oblong shape, that opens to the outside of the brush border. What is this strucutre?
Goblet filled with mucopolysaccharides
What type of filaments are in stereovilli?
Actin
Where are sterovili found (2)?
male reproductive ducts
Inner ear
What are the two major differences in sterocili(villi) versus microvilli?
Stereovilli are basically (1) longer versions of microvilli with (2) cytoplasmic bridges to cross link actin filaments
What is the triad of signs/symptoms of Kartagenar syndrome?
- Chronic sinusitus
- Bronchiectasis
- Situs inversus
What causes Kartagenar syndrome?
Defective dynein arms lead to immotile cilia and flagella
