give definition for epithelial tissue
Answers
Epithelial tissue
• Forms the outermost covering of the body, body cavity, and internal organs.
• It separates different organ systems in the body.
• Cells are arranged as tightly- packed continuous sheets, without any intercellular space.
• They are found in the surface cells of skin, buccal cavity, blood vessels, alveoli, and kidney tubules.
Based on different shapes of epithelial cells, epithelium can be broadly classified as
• Squamous epithelium
• columnar epithelium
• cuboidal epithelium
(i) Squamous and stratified squamous epithelium
• Present as thin, delicate, flat lining.
• Present in the lining of the mouth, oesophagus, and skin.
• Skin forms a protective covering on the body surface, it often gets damaged. Therefore, it is present in multiple layers. This is called stratified squamous epithelium.
(ii) Columnar and ciliated columnar epithelium
• Columnar epithelial cells are pillar-like cells.
• They are present in the inner lining of the intestine and respiratory tract.
• Their functions include secretion of mucus and absorption of digested food.
• Columnar epithelial cells are often marked by the presence of cilia. Cilia are hair-like projections coming out of cells. Cilia can move freely. This helps the mucus to move forward. These cells are called ciliated columnar epithelium.
(iii) Cuboidal epithelium
•Cuboidal epithelium is composed of cube-shaped epithelial cells.
• They are present in the lining of kidney tubules and ducts of salivary glands.
• Some special cells form the surface of secretory glands and gland cells.
•Glandular epithelium is often formed by the inward folding of epithelial tissues.
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Answer:
epithelial tissue is simple tissue.it is a protective tissue of the animal body<as epidermis of plant>
Explanation:
it is a between tissue muceles and blood