Due to their structure and the ability to divide fast, these cells provide protection in the event of trauma to the epidermis or the digestive tract. In case of an injury, the damaged cells get replaced by new cells, which facilitates faster healing. Though the epithelial tissues don't have blood vessels, nutrients diffuse through the underlying connective tissue layers that contain several blood vessels.
The nucleus of each of the cells is usually placed quite close to the thin, sheet-like basement membrane. Most of the nuclei are placed at the same level. The epithelium has a free surface, which is referred to as the atypical surface. Its basal surface or the attached surface, lies on the underlying layer of connective tissue. The basal membrane is composed of collagen and glycoproteins that are produced by cells of the underlying connective tissue layer, as well as the epithelial cells themselves.
This type of epithelium could have cells that are ciliated or non-ciliated. Cilia refers to hair-like projections arising from the free surface of these cells. The length of these projections could be between 7 and 10 μm.
● Fallopian tubes in females
In women, the simple columnar ciliated epithelial cells facilitate the movement of the egg cell through the Fallopian tube to the uterus. As the name suggests, non-ciliated simple columnar epithelium does not have cilia. It is found at the following places in the human body:
● Ducts of exocrine glands
● Small intestine
● Large intestine
● Goblet cells