Table of Contents
Simple Columnar Epithelium Definition
Simple Columnar Epithelium is a type of Epithelial tissue in which the cells are always taller than their width and they have cilia or microvilli at the apex of these cells that are often specialized for absorption the apical ends of these cells have complexes of tight junctions and adherent junctions (commonly known as terminal bars in light microscopic images). Some authors describe columnar epithelium as being Simple only when it has no specializations at the apical ends (no microvilli and cilia) however, this is not correct as epithelial tissues are generally classified as simple (having one layer of cells) or stratified (when the epithelium has more than one layer of cells).
When the vertical section the simple columnar epithelial cells are viewed, the cells appear rectangular whereas the surface view (or transverse section) shows the cells as being polygonal. The nuclei of these cells are also frequently elongated as the cells.
Simple columnar epithelium: some have cilia while others do not have.
Classification of Simple Columnar Epithelium
Columnar epithelium can be classified according to the nature of the free surfaces of the cells as ciliated columnar epithelium (with a single layer of rectangular cells having cilia on apical surface) and non-ciliated or striated columnar epithelium.
Simple Columnar Epithelium Function
Simple columnar epithelium functions mainly in absorption and secretion with those having cilia helping in the generation of current across the epithelium such as those lining the fallopian tube. The simple columnar epithelium lining the large intestine has isolated goblet cells that secrete mucus into the GIT.
Where is Simple Columnar Epithelium Found?
Simple Columnar Epithelium can be found lining the oviduct, gall bladder, renal collecting ducts and many other ducts of the body.
A simple columnar epithelium with cilia
Simple Columnar Epithelium Location
- Lining of gall bladder
- The hepatic duct
- The cystic duct
- Common bile ducts (the simple columnar epithelial cells lining this duct are called cholangiocytes)
- The secretory cells in the ducts of the seminal vesicles are simple columnar epithelial cells
- Each of the paired bulbourethral glands (also known as Cowper glands) has several lobules with tubule-acinar secretory units that are lined by a mucus-secreting simple columnar epithelium
- The endometrium of the uterus is lined by simple columnar epithelium
- Simple columnar epithelium lines the intralobular ducts of the pancreas
- Renal collecting ducts
- The endocervical mucosa of the cervix is a simple columnar epithelium
Lining of the oviduct (this has both the ciliated and secretory columnar epithelial cells)