Histology- Epithelial cells Flashcards
How small can a light microscope see?
as small as .2 microns
2 types of light microscopy and difference
fluorescence- fluorescent probe
confocal- particular plane (can’t see plane above or below, thin almost 2-D image)
Which type of microscope can view living or dead cells?
light
Which type of microscope uses tissues that are frozen in liquid nitrogen, coated in gold, and dead?
electron
4 steps of tissue prep for light microscope?
1.) fixation: chemicals cross-link proteins and inactivate degradation enzymes
2.) dehydration and clearing: with alcohol solutions
3.) infiltration and embedding- waxxed and hardened
4.) trimming: sliced thin, transparent
loaded with dye to improve visualization (staining)
What is it called when cells are stained with fluorescent antibodies that bind to a very specific molecular structure?
immunohistochemistry
Which 2 dyes are usually done together in light microscopy and what colors are they? Basophilic or acidophilic?
hematoxylin-dark blue- basophilic
eosin-pink-acidophilic
What stain is great at showing glycogen and glycoproteins, as well as cytosol, mucous, and some ECM?
PAS- periodic acid-Schiff stain
Which stain is used to see proteins and+ charged molecules?
eosin
Which stain is used to see DNA, - charged molecules and nuclei?
hematoxylin
Trichrome stains which areas what color?
conn. tissue=blue
nuclei=dark red/purple
cytoplasm=red/pink
Functions of epithelial cells?
protection, transport, secretion
Is epithelium vascular?
no
Simple squamous epi. location and function?
lungs, heart, blood vessels, lymph vessels
diffusion, filtration, secretion
EXCHANGE EPITHELIUM
Simple cuboidal epi. location and function?
ducts, secretory portions of small glands, kidney
secretes, absorbs
TRANSPORT EPITHELIUM
Simple columnar epithelium?
ciliated tissues, bronchioles, uterine tubes, microvili
absorbs, secretes mucous and enzymes
CILIA= MOTILITY
MICROVILI=increase surface area
Difference between simple and stratefied?
simple=1 layer
strat= more than 1
Pseudostratified columnar epi. location? function?
ciliated, bronchi, trachea, resp. tract
secretes mucous
Stratified squamous epi, location, function?
esophagus, mouth, vagina, SKIN
protects against abraision
Transitional epi. Location? function?
bladder, urethra, ureters
stretch of urinary organs
CHEMICAL PROTECTION from urine
Function:
1.) actin
2.) int. filaments
3.) microtubules
1.) shape, motility (actors have nice shape and move on stage)
2.) structural “strength” (Des is an int. student filled with strength and doing K)
3.) polarity, cell division, cilia (microdick could cause polarity and division in a relationship)
What kind of conn. tissue are desmin and keratin?
int. filaments
Tight junctions
1.) location
2.) functions
1.) apical aspect of almost ALL epithelial cells. gut, brain, skin, resp. tract. CLOSEST to lumen
2.) barrier, regulate movement, est. polarity, direct memb. proteins
Most common proteins in tight junctions?
Claudins (small molecules)
Occludin
junctional adhesion molecules (JAM) (permeability)
ZO-proteins (interaction)
(These guys are TIGHT but Claud, Occy and JAM are all trans. But their friend ZO, says NO, and is still in the closet with his skeletons, but introduces them to his skeletons)
What are found immediately below TJs?
adherens junction
In order to stay TIGHT, junctions must have adherens!
Adheren key proteins
Cadherin and catenin (beta-catenin=signal OR connect with cadherin)
We must adhere to the rules. Cad is trans and has an cat that must stay inside who likes fish skeletons.