[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Histology](https://durgical.com/en/histology/) › [Epithelium](https://durgical.com/en/histology/#a-epithelium) › Simple, stratified, pseudostratified and transitional epithelium [Histology](https://durgical.com/en/histology/) · [Epithelium](https://durgical.com/en/histology/#a-epithelium) # Simple, stratified, pseudostratified and transitional epithelium - Tissue How the main covering epithelia look under the microscope, and why each organ has the lining it has. Updated 2026-11-01 **See it in 3D:** [Trachea](https://durgical.com/en/anatomy/trachea/) · [Esophagus](https://durgical.com/en/anatomy/esophagus-abdominal-part/) · [Urinary bladder](https://durgical.com/en/anatomy/urinary-bladder/) · [Skin](https://durgical.com/en/anatomy/skin/) ## Key points - Endothelium and mesothelium are simple squamous. - Intestine: simple columnar with microvilli (brush border) and goblet cells. - Trachea: pseudostratified ciliated columnar with goblet cells. - Urothelium: umbrella cells; lines calyces to proximal urethra. - Keratin is present only in skin epidermis among the covering epithelia of the body surface. ## What it is Each covering epithelium is built for the job of its surface. Thin single layers let gases and fluid pass; tall columnar cells absorb and secrete; many layers of flat cells protect against wear; a stretchy urothelium holds urine. On an H&E slide the epithelium is identified by counting its layers, looking at the shape and position of its nuclei, and checking the apical surface for cilia, microvilli or keratin. ## Structure - Simple squamous: a single row of flat cells whose nuclei bulge into the lumen like fried eggs seen from the side; endothelium and mesothelium are this type. - Simple cuboidal: one row of cells as tall as they are wide, with round central nuclei, as in kidney tubules and thyroid follicles. - Simple columnar: tall cells with oval nuclei lined up near the base; in the intestine a pink brush border (microvilli) and pale goblet cells sit among them. - Pseudostratified ciliated columnar: nuclei crowded at several heights, a fringe of cilia on top and goblet cells; every cell reaches the basement membrane. - Stratified squamous: a basal layer of dividing cuboidal cells that flatten toward the surface; keratinized skin adds a pink anucleate keratin layer. - Transitional (urothelium): several layers topped by large dome-shaped umbrella cells, sometimes binucleated, that flatten when the bladder is full. ## Function - Simple squamous: fast diffusion and filtration. - Simple columnar: absorption with microvilli, mucus secretion by goblet cells. - Pseudostratified ciliated: traps particles in mucus and sweeps them toward the pharynx. - Stratified squamous: protection where friction is high. - Urothelium: distension without leaking; the umbrella cells form a barrier to urine. ## Clinical notes - Barrett esophagus: chronic reflux turns the lower esophageal squamous lining into columnar epithelium with goblet cells, a precursor of adenocarcinoma. - Cigarette smoke paralyses cilia and causes squamous metaplasia in the bronchi, so mucus clearance fails. - Most bladder cancers arise from the urothelium (urothelial carcinoma); smoking is the main risk factor. - In asthma the airway epithelium shows more goblet cells and a thickened basement membrane zone. ## Memory aid Thin to pass, tall to absorb, piled to protect, stretchy to store. ## Test yourself Think of the answer, then tap the question to see it. ## Which cells on the luminal surface identify urothelium on a slide? Large dome-shaped umbrella cells, sometimes with two nuclei, that flatten when the bladder stretches. ## What two apical features distinguish small-intestinal from tracheal epithelium? The intestine has microvilli (a brush border) on simple columnar cells; the trachea has motile cilia on pseudostratified cells. ## What change in epithelium defines Barrett esophagus? Metaplasia of stratified squamous epithelium into intestinal-type columnar epithelium with goblet cells in the distal esophagus. ## Why is stratified squamous epithelium found in the esophagus rather than simple columnar? Swallowed food causes friction; many layers of cells that are constantly replaced from the basal layer protect against abrasion. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/histology/simple-stratified-pseudostratified-and-transitional-epithelium/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Trachea](https://durgical.com/en/anatomy/trachea/) - [Esophagus](https://durgical.com/en/anatomy/esophagus-abdominal-part/) - [Urinary bladder](https://durgical.com/en/anatomy/urinary-bladder/) - [Skin](https://durgical.com/en/anatomy/skin/) ## Related - [Epithelium: classification (the table to know)](https://durgical.com/en/histology/epithelium-classification/) - [Basement membrane](https://durgical.com/en/histology/basement-membrane/) - [Cilia, microvilli and stereocilia](https://durgical.com/en/histology/cilia-microvilli-and-stereocilia/) - [The airway: from nose to bronchioles](https://durgical.com/en/histology/the-airway-from-nose-to-bronchioles/) - [Esophagus and the Barrett change](https://durgical.com/en/histology/esophagus-and-the-barrett-change/) - [Ureter, bladder and urethra: urothelium](https://durgical.com/en/histology/ureter-bladder-and-urethra-urothelium/) - [Skin: epidermis layers, dermis, hypodermis](https://durgical.com/en/histology/skin-epidermis-layers-dermis-hypodermis/) ## Related conditions - [Gastro-oesophageal reflux disease (GERD)](https://durgical.com/en/conditions/gastro-oesophageal-reflux-disease/) - [Asthma](https://durgical.com/en/conditions/asthma/) - [Bladder cancer](https://durgical.com/en/conditions/bladder-cancer/) [← All of histology](https://durgical.com/en/histology/) Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice. Sources: [4.2 Epithelial Tissue](https://openstax.org/books/anatomy-and-physiology-2e/pages/4-2-epithelial-tissue) (OpenStax, 2022); [Epithelial Tissue](https://training.seer.cancer.gov/anatomy/cells_tissues_membranes/tissues/epithelial.html) (National Cancer Institute, SEER Training Modules, 2024). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/histology/simple-stratified-pseudostratified-and-transitional-epithelium/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/histology/simple-stratified-pseudostratified-and-transitional-epithelium/