Animal Tissues : Class 9 Science CBSE
Epithelial Tissue
What are Epithelial tissues?: The covering or protective tissues in the animal body are epithelial tissues. It also forms a barrier to keeping different body systems separate. Epithelial tissue cells are tightly packed and form a continuous sheet, the cells have no internal spaces between them.
It covers the entire body, anything entering or leaving the body must cross 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 also between different parts of the body.
The function of Epithelial tissue:
Protection: Epithelial tissues help us to defend against mechanical injury, chemical exposure, excessive fluid loss, and infections.
Absorption: The lining of epithelial tissue in the digestive tracts absorbs water and nutrients. Epithelial tissues regulate exchange the of material between different parts of the body.
Sensation: Epithelial tissue contains sensory receptors that help to transmit signals from external stimuli to the brain.
Secretion: Various glands made up of epithelial cells secret hormones, enzymes, saliva, mucus, sweat, etc.
Structure of Epithelial tissue: Different epithelia show differing structures that correlate with their unique functions. For example, in cells lining blood vessels or lining alveoli, where transportation of substances occurs through a selectively permeable surface, there is a simple flat kind of epithelium.
