Epithelium

Epithelium is a type of tissue that forms the covering and lining of many organs and structures of the body. It is made of one or more layers of tightly packed cells that form an integrated barrier against physical, chemical, and microbial invasion. The functions of epithelium are numerous and include protection, secretion, absorption, gas exchange, and sensory perception. Its presence is necessary for the normal functioning of the body, and it is vital for the maintenance of homeostasis. Its importance is highlighted by the fact that diseases such as cancer can occur when the epithelium is disrupted.