Histology Flashcards
Tissue Definition
Group of similar cells, usually common embryonic origin, that function together to carry out specialized activities
What is epithelial tissue?
- Closely adhering sheets of cells
- Avascular, single or multiple layers
- Mostly uninucleate, polyhedral polarized cells
- apica vs lateral vs basal
- Basement membrane seperates it
- Cells undergo regular turnover
Basement Membrane
What is it, composed of, function?
- Extracellular selective filter btw epithelium and connective tissue
- Acellular
- ADDITIONAL INFO NOT NEEDED
- Composed of
- Collagen (Types 4 and 7)
- Proteoglycans
- Laminin, entactin, fibronectin
- Reticular fibers (CT)
- Controls cell growth, metabolism and differentiation
Where is epithelial tissue throught out the body?
Cover body surfaces on or within
Line internal cavities
Present in organs and glands
Line ducts
What does epithelial tissue do?
Protects, absorbs, secretes, transports, contracts, filters, sensory
Epithelial cell shapes
Squamous
Cuboidal
Columnar (Villi and cilia)
Transitional (Bladder)
Epithelial Layer types
Simple
Layered–> Stratified
Pseudostratified (usually cilia)
Endothelium and Mesothelium
Mesodermally derived simple squamous epithelium
Endothelium lines blood and lymph vessels
Mesothelium lines organs and body cavities
Epithelial Microvilli
Microvilli (closely spaced)
Microfilaments
Striated border
Brush border
Enhace absorption
Stereocilia
Elongated microvilli
AKA stereovilli
wont really test bc of misnomer
Cilia
Elongated motile extension
Made out of microtubules
Moves fluid and particles
Epithelial Secretory Adaptions
Specialized epithelial cells have a basal level of secretion under hormonal/nervous control
Can secrete
Protein, mucin, lipid (steroid), ions and water
Epi cells that produce/secrete protein
Well developed rough ER
