Define Integrity of Epithelial Tissues?

Vitamin A is essential for the integrity of the mucous-secreting cells. In fact vitamin A maintains the health of epithelial cells that line internal and external surfaces of the lungs, intestines, stomach, vagina, urinary tract and bladder eyes and skin. These cells act as important barriers to bacteria. Certain epithelial cells secrete mucous to keep the skin, eyes and other mucous membranes moist. In deficiency, the epithelial tissues are keratinized. The tissues affected are salivary glands, respiratory tract, eyes, skin and sex organs.