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Epithelium tissue and its types?

Answer» \tEpithelial Tissue: It is the simplest tissue and protective in nature. The cells of this tissue are tightly packed and they form a continuous sheet. They contain a very little or no intercellular space. It covers most organs and cavities within the body. The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue. 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.\xa0\xa0\tEpithelium typeCharacteristicsShape of cellsFunctionSquamousIt is made up of thin, flat and irregular-shaped cells. It forms the delicate lining of cavities (mouth, oesophagus, nose, etc.) and blood vessels. \xa0\xa0It protects the underlying parts of body from mechanical injury, entry of germs, chemicals and drying. \xa0CuboidalIt consists of cube-like cells. These are found in kidney tubules, thyroid vesicles and in glands.\xa0It helps in absorption, secretion and excretion. It also provides mechanical support.ColumnarIt consists of cells which are taller than broader i.e. pillar-like. It forms the lining of stomach, small intestine and colon.\xa0Its main function includes absorption and secretion.CiliatedThey are cubical or columnar cells with cilia. These are found in sperm ducts and line the trachea, bronchi, kidney tubules and oviducts.\xa0The rhythmic, concerted beating of the cilia moves solid particles in one direction through the ducts.GlandularThe columnar epithelium is modified to form glands which secrete chemicals.\xa0Its main function is secretion.\t


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