Epithelial tissues are consisting of closely packed cells without intertwining inter cellular substances .
Epithelial cells arise from basement membrane.
Basement membrane contain connective tissues and nerve endings.
Epithelium covers all the free surfaces of the body, epithelium also ling large internal body cavities, no blood vessels present.
Epithelial tissue can be classified according to the number of cell layers present on the basement membrane.
Epithelial tissue can be divided into two types,
1. Simple epithelial
2. Stratified epithelial
Simple epithelial tissue can be divided into three types,
1. Simple cuboidal epithelial
2. Simple columnar epithelial
3. Simple squamous epithelial
1. Simple squamous epithelial,
Single layer of flattened cells with disc shape central nuclei.
Air sacks of lungs lining of the path of blood and lymphatic vessels .
Functions,
delicate nature of these membrane permits gas exchange
2. Simple cubodial epithelial tissue,
Cells are cubodial with globular nucleus in the middle.
Location,
* covering ovaries
* Kidney tubules
*Lining of some glands
Functions
Secretion
Absorption
3. Simple columnar epithelial tissue,
Single layer of column shape cells with oval nuclei. Some cells bear cilia .
Location,
* Most of the digestive track
* Path of respiratory track
Functions,
* Provide protection
* Functions in secretion and absorption