Epithelial Tissue - Beni-Suef University PDF

 Classification of epithelial tissue: Lining and Simple covering epithelium Stratified Epithelial Glandular tissue ep...

 Classification of epithelial tissue: Lining and Simple covering epithelium Stratified Epithelial Glandular tissue epithelium Specialized epithelium  Squamous cuboidal Simple columnar Lining and Pseudostratified columnar covering epithelium squamous cuboidal Stratified columnar transitional ▪ Stratified epithelium  Stratified squamous epithelium Stratified squamous non keratinized Stratifed squamous epithelium keratinized epithelium 1. Basal layer: one layer of columnar Resmble non keratinized cells with basal oval n. but superficial layer 2. Intermediate layers: several covered by non living structure layers of polyhedral cells with keratinized layer central spherical n. 3. Superficial layers: few layers of flat cells with elongated n. Wet surfaces: Epidermis of skin Oesophagus Hard palate sites Anal canal Vagina proper Oral cavity of ruminants External surface of cornea Dorsal surface of the tongue Stratified squamous non keratinized epithelium Stratified squamous keratinized epithelium  Transitional epithelium  Site: urinary passages as renal pelvis, urinary bladder and ureter.  Change its form according to state of the organ:  In empty bladder: consists of 6-8 layers: Basal layer: one layer of high cuboidal cells with central spherical n. Intermediate layers: several layers of polyhedral cells with central spherical n. Superficial layer: one layer of dome-shaped cells with central spherical n.,some cells are binucleated.  In full bladder: number of layers decreases to 2-3 layers. Superficial layers: flat with rounded n.  Allow the urinary bladder to distend without ruptuing.  Glandular epithelium  Cells of epithelial tissue are specialized for secretion. Classified according to presence or abscence of duct into: 1.Exocrine gland: formed of secretory part and duct system ex:salivary gland. 2.Endocrine gland: formed of secretory part, duct system is absent ex: adrenal gland and pituitary gland. 3.Mixed gland: consists of exocrine part with ducts and endocrine part lacking ducts ex: pancreas and liver  Exocrine glands are classidied according to number of cells into: 1.Unicellular gland: formed of one cell as goblet cell. 2.Multicellular gland: formed of large number of cells as salivary gland  Goblet cell  Unicellular gland specialized to produce glycoprotein.  Scattered singly between the epithelial cells of respiratory and digestive system.  It has upper extended part which contains secretory granules (mucigen granules) & lower narrow part contain the nucleus  By H&E: the upper part appear foamy & pale as the granules are not stained leaving empty spaces.  The granules could be stained by special stains as: PAS appear pink and Alcian blue appear blue Goblet cell stained by H&E