What is True regarding epithelial cells are: and explain in detail?
Ref: The Developing Human Clinically Oriented Embryology,8th edition. Page 441 and Histology A Text and Atlas, Michael H.Ross, 6th edition. Pages 134, 666 and 725Explanation:Sebaceous glands develop as buds from the sides of developing epithelial root sheaths of hair follicles.The glandular buds grow into the surrounding connective tissue and branch to form the primordia of several alveoli and their associated ducts.The central cells of the alveoli break down, forming an oily secretion (sebum), which is released into the hair follicle and passes to the surface of the skin, where it mixes with desquamated peridermal cells to form vernix caseosa.Sebaceous glands independent of hair follicles (e.g., in the glans penis and labia minora) develop in a similar manner to buds from the epidermis.Note:Upper respiratory tract is lined with ciliated pseudo stratified columnar epithelium.Ureter does NOT contain abundant goblet cells. Abundant goblet cells are features of large intestine.Epithelium is NOT surrounded by single layered membrane.Epithelial cells have strong adhesion molecules, membrane interdigitations and intercellular junctions.These features allow the cells to form cellular sheets that cover the surface of the body and line its cavities.Epithelial cells are separated from the connective tissue by a sheet of extracellular material called the basal lamina.Types of EpitheliumType of EpitheliumSubtypesLocations * Endothelium* Linings of Alveoli* Linings of Cavities* Lining of Serosa (Pori cardium. Pleura and Peri toneum)* Bowman s capsule* Thin segment of Loop of Henle* Vagina* Cornea* Upper aerodigestive tract* Mouth* Tonsils* Pharynx* Vocal cords* EsophagusSimpleSquamousStratified. Non- keratinizedStratified, Keratinized* Skin* Duct of sebaceous glands* Anas below Hilton's white lineSimple. Non-ciliated* Mucosa of Stomach* Intestine* Gallbladder* Cervical canal * Uterus* Fallopian tubes* Endocervix* Eustachian tubeCiliatedColumnar * Middle ear* Respiratory epithelium* Upper 1/3rd nasal cavity (Olfactory epitheliums)Pseuriost ratified. Ciliated* Respiratory epithelium (Lower 2/3rd of nasal cavity, auditory tube, trachea. bronchi, Respiratory tract upto bronchioles)* Ductus deferensPseudostratified with stercocilia* Epididymus Simple* Terminal bronchioles* Alveoli* Germinal epithelium * Ducts of Glands* Pancreas* Salivary glands* Sweat glands* Lining ot Bartholin glandsCuboidalStratifiedTransitionalepithelium * Urinary passage (from minor calyces, renal pelvis, ureter, urinary bladder, prostatic urethra)Urothelium