2. Epithelial Flashcards
Simple vs compound
Single layer
Many layers of cells
Both = joined by specialised junctions on a basement membrane
Function of goblet cells
Secrete mucous (paler)
More in large intestine than small
Function of microvili
Increases surface area for absorption
(Stain magenta with PAS)
H&E stain
Hematoxylin and Eosin stains negative DNA blue and positive mitochondria+cytoplasm pink
PAS stain
Periodic Acid-Schiff stains structures rich in polysaccharides, glycolipids etc reddish purple
Osmium stain
Blackens lipids and Golgi apparatus
Where can cuboidal epithelia be found?
Gland ducts e.g. sweat, saliva, pancreas and kidneys
What is keratin
A dense protein that renders the cytoplasm tough and waterproof by restricting movement of water.
Once keratin enter cells, they will die and detach
Precursor of keratin
Keratohyaline granules
(Stain blue between pink cells and red dead keratinised cells)
Basement membrane made from
Extracellular protein
Type 4 collagen
Fibronectin
Serous vs Mucous cells
Serous - round nuclei, darker cells produces enzymes to digest food
Mucous - Paler cells flattened at edge produces mucous to lubricate
Describe uroethlium
Looks pseudo-stratified but is stratified.
Upper umbrella cells are waterproof
Lines bladder, urinary tracts etc
Tight vs gap junctions
Tight - prevents leakage of molecules so waterproof
Gap - allows small water soluble ions and molecules through
3 more types of junction
Adherens - Joins actin bundles in cells
Desmos ones - Joins intermediate filaments in cells
Hemidesmosomes - Anchors intermediate filaments to basal lamina
Proteins involved in ciliary movement to transport mucous to larynx
Tubulin and Dyenin
