give function location of different types of epithelial tissue........class 9
Answers
Answer:
They form the covering of the external surfaces, internal cavities and organs of the animal body.
Epithelial tissue cells are tightly packed and form a continuous sheet.
The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.
Functions of Epithelial Tissue:
(i) Epithelitum covers most organs and cavities within the body.
(ii) It also forms a barrier to keep different body systems separate.
(iii) The permeability of the cells of various epithelia play an important role in regulating the exchange of materials between the body and the external environment.
Types of epithelial tissues:
Various types of epithelial tissues are:
(a) Simple squamous epithelium: In cells lining blood vessels or lung alveoli, where transportation of substances occurs through a selectively permeable surface, there is a simple flat and extremely thin kind of epithelium which is named as simple squamous epitheliun.
It is found in the lining of the mouth, oesophagus, lung, alveoli, etc.
(b) Stratified Squamous Epithelium: The skin, which protects the body, is also made of squamous epithelium.
Skin epilhelial cells are arranged in many layers to prevent wear and tear. Since they are arranged in a pattern of layers, the epitheliunim is called stratified squamous epithelium.
(c) Cuboidal epithelium: This is cuboidal in shape and forms the lining of kidney tubules and ducts of salivaiy glands.
In some cases a portion of the epithelial tissue folds inward to form a multicellular gland. This is called glandular epithelium.
It performs a function of secretion and absorption.
(d) Columnar Epithelium: Where absorption and secretion occur, as in the inner lining of the intestine, tall epithelial cells are present and are named as cohunnar epithelium.
In the respiratory tract, on the outer surfaces of epithelial cells there are hair like projevtions called cilia. These cilia can move, and their movement pushes the mucus forward to clear it. This type of epithelium is named as ciliated columnar epithelium.
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Answer:
Epithelial tissues are widespread throughout the body. They form the covering of all body surfaces, line body cavities and hollow organs, and are the major tissue in glands. ... Simple cuboidal epithelium is found in glandulartissue and in the kidney tubules. Simple columnar epithelium lines the stomach and intestines.