Epithelial Tissue Flashcards
Endothelium
Simple stratified; lines blood vessels
Endothelium
Simple squamous; lines ventricles of the heart
Mesothelium
Simple stratified; lines the body cavities (peritoneal, pericardial, pleural)
Endothelium
Simple squamous; lines ventricles of the heart
Mesothelium
Simple squamous; lines the body cavities (peritoneal, pericardial, pleural)
Transitional epithelium - location, structure, and functions
AKA Urothelium
Transitional epithelium - location, layering(?), and key feature
AKA Urothelium
Located lining the lower urinary tract
Structure: stratified
Key feature: special morphology with distensible properties
Pseudostratitfied epithelium
Appears stratified b/c some cells do not reach the free surface, but ALL cells rest on the basement membrane (which is why it is considered simple)
What key feature does an epithelial lining have to have to be considered “simple?”
ALL cells must be in contact/resting on the basement membrane
Tarsal (Meibomian) glands
In eyelid; use holocrine secretion to expel lubricating substance onto the surface of the eye
State the main 3 functions of the epithelium
Protection, absorption, secretion
Name the five types of apical specialization
Ciliated, microvilli, stereociliated, keratinized, and secretory (lots of sub-types)
Basal lamina - location, composition, functions
Part of the basement membrane that is closest to the epithelial layer.
Contains type IV collagen and laminin (large glycoproteins that bind with integrin proteins in the basal cell membrane of epithelia
Functions: scaffolding, filtration
Laminin
Large glycoproteins in the basal lamina that bind to integrin proteins on basal side of the epithelial cells
Reticular lamina - location, composition, and functions
Layer of basement membrane that is closest to the connective tissue layer
Composed of type III collagen
Main function: anchoring the BM to the connective tissue
Zonula Occludens - common name, function, major transmembrane link proteins, and cytoskeleton components
Tight Junction
Functions: SEALS adjacent cells together; separates apical and basolateral membrane domains;
Transmembrane proteins: occludins, claudins, ZO proteins
Cytoskeleton: actin filaments
Name the essential cell junction in the fetal blood-brain barrier
Zonula occludens (tight junctions) - defects in occludin proteins in the fetal BBB can cause severe neuro defects
Zonula Adherens
Adherens Junctions
Function: strengthens and stabilizes nearby tight junctions by linking neighboring cells’ cytoskeletons
Transmembrane proteins: E-cadherins, catenin complexes
Cytoskeleton comp: actin
Macula Adherens
Desmosomes
Function: strengthening tissues via strong intermediate filaments coupling between neighboring cells
Transmembrane link proteins: Desmogleins, desmocolin (parts of the Cadherin family of proteins)
Cytoskeleton components: intermediate filaments, including desmoplakin
