Hello friend this is your answer..

All epithelia have an upper surface designed for PROTECTION, sensing and secretion, and a lower surface designed to pass materials into cells under the surface (called apical basal polarity). Most upper surface cells have small hair-like extensions that increase surface area to absorb or secrete SUBSTANCES. Thicker plasma membrane extensions are called microvilli and thinner ones are called cilia. Cilia move to carry materials along the surface. Epithelial cells form sheets of closely fitting cells with openings for gland cells, hairs, pores and sensory cells. All epithelia are supported by connective TISSUE such as COLLAGEN protein fiber which helps it resist stretching and tearing. Epithelia does not contain blood vessels or capillaries (called avascular). Epithelia usually has nerve fibers (called innervated) to control secretion, absorption, sensing, and contractions of muscle fibers. Epithelial calls regenerate quickly to heal from LOSS of tissue and injury.

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