What are the importance of tissues

Anything entering or leaving the body crosses at least one layer of epithelium. As a result, the permeability of the cells of various epithelia plays an important role in regulating the exchange of materials between the body and the external environment and also between different parts of the body. All the epithelium is usually separated from the underlying tissue by an extracellular fibrous basement membrane..

Functions of epithelial tissues:

1. They form the outer lining of the skin and protect the underlying cells from drying, injury and chemical effects.
2. They form the lining of mouth and alimentary canal and protect these organs.
3. They help in absorption of water and nutrients.
4. They help in elimination of waste products.
5. They form secretory function by secreting a variety of substances such as sweat, saliva, enzymes, etc.