In 1909, Western Union and ADT came under the control of American Telephone & Telegraph Company (AT&T). ADT began to expand into new areas, such as fire alarms and security alarms between 1910 and 1930, but was kept separate from AT&T's Holmes alarm business. ADT became a publicly owned company in the 1960s.
It has moist membranes. Many, but not all (urinary), secrete mucous. Serous: Lines open body cavities that are closed to the exterior body surface. composed of simple squamous epithelium resting on thin layer of areolar connective tissue.
Two forms occur in the human body: 1  Covering and lining epithelium â forms the outer layer of the skin; lines open cavities of the digestive and respiratory systems; covers the walls of organs of the closed ventral body cavity. 2  Glandular epithelium â surrounds glands within the body.