Classify and describe epithelial tissue on the basis of structural modifications of cells.
Answer -
Epithelial tissues are categorised into three distinct types. This categorisation is done based on structural modification of cells and organisation.
- Squamous epithelium
These tissues are composed of a single thin layer of flattened cells. The cells of these tissues possess irregular boundaries and are usually found in the walls of
blood vessels and air sacs of the lungs. The thinness of this tissue ensures that diffusion can be facilitated across the boundary.
- Cuboidal epithelium
These tissues consist of a single layer of cuboidal cells. The tissue is usually found in the ducts of various glands and the nephrons. The tissue performs the key function of secretion and absorption in the body.
- Columnar epithelium
These tissues are composed of a single layer of slender and long cells. The nucleus is usually created at the base of the cells. Moreover, microvilli are also
located at the top portion of these slender cells. The columnar epithelium is commonly found in the stomach lining and the intestine. The key function of this
tissue is to perform secretion and absorption activities.
- Ciliated epithelium
These tissues are commonly located on the cuboidal and columnar epithelium tissues. The key function performed by these tissues is to provide movement of
substances.