Group of similar cells and their intercellular substance; similar origin in embryo; function together to perform specialized activity.
Epithelial (Classification & Function)
Cover body surfaces; lines body cavities & ducts; form glands.
Epithelial tissues consist of...
Largely or entirely of closely packed cells with little or no intercellular material between adjacent cells.
Epithelial tissues are arranged in...
Continuous sheets - nerves may extend through sheets, but blood vessels do not (avascular).
Epithelial tissues overlies and...
Adheres firmly to basement membrance (CT).
Arrangement of Layers
Simple, Stratified, & Pseudostratified
Single layer; absorption & filtration; areas of minimal wear & tear.
Several layers; stacked; areas of high degree of wear & tear.
One layer; some layers do not reach surface; multi-layered (stratified) appearance; columnar epithelial tissue.
Squamous, cuboidal, columnar, & transitional.
Hexagons (sometimes); cube shaped in cross section.
Distension (expansion); combination of shapes.
Simple Squamous ET
Lines blood vessels & air sacs; serous membranes.
Simple Cuboidal ET
Lines kidney tubes & ducts of glands.
Cilitated Simple Stratified Columnar ET
Upper respiratory tract; fallopian tubes.
Non-ciliated Simple Columnar ET
Keratinized Stratified Squamous ET
Non-Keratinized Stratified Squamous ET
Lining of mouth, esophogus, vagina.
Urinary bladder, ureters, urethra
Ciliated Psedostratified Columnar ET
Non-Ciliated Psedostratified Columnar ET
Lines larger ducts of glands, male urethra.
Exocrine Glandular ET
Oil glands & sweat glands.
Endocrine Glandular ET
Secretes hormones; pituitary gland, thyroid gland, parathyroid glands, thymus gland, pineal gland.