•TISSUE: An integrated group of cells with a common structure and function
•Four Major tissue types:
Epithelia
Connective
Muscle
Nervous
Epithelial tissues
characteristics
•Covers or lines organs
•Avascular
•Always has a free (unattached) surface - apical
•Basal surface in contact with basement membrane
•Basement Membrane
What is a basement membrane?
•Basement Membrane: an cellular material made by the epithelium above it and the connective tissue below it --- it anchors the epithelium to underlying tissue
Classifactions of epithelia?
•According to number of layers
simple -- one cell layer thick
stratified -- two or more cell layers thick
•According to cell shape
squamous (flattened)
cuboidal
columnar
function and location of simple squamous
•Functions in diffusion and filtration
•Locations:
–Walls of capillaries (endothelium)
–Serous membranes (mesothelium)
–Alveoli
function and location of simple cuboidal
•Functions in secretion and absorption
•Locations:
–Renal tubules
–Glands
–Lower parts of respiratory tree
Simple columnar
functions and locations
•Functions in secretion (including mucous) and absorption
–If ciliated -- involved in movement of materials
•Locations:
–Digestive tract
Glands
pseudostratified columnar
function and location
•Functions in protection, mucous secretion and movement of materials
•Location:
–Upper respiratory tract
Stratified Squamous
functions and location
•Functions in protection of underlying tissues
•Locations:
–Moist: lining mouth, parts of pharynx, larynx and esophagus