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.
Cells that line surfaces. Epithelium is the name given to the cells that line a surface. The outer surface of the body is lined by an epithelium called the epidermis. The inside of the body cavity is also lined by an epithelium, as is the outer surface of many internal organs.The inner surfaces of all the tubes and ducts of the body are also lined by epithelia, whether they open to the outside (eg. digestive system, reproductive system) or are enclosed (eg. cardiovascular system).Glands (eg. sweat glands, salivary glands, liver) are also formed by epithelial cells.he inner surfaces of all the tubes and ducts of the body are also lined by epithelia, whether they open to the outside (eg. digestive system, reproductive system) or are enclosed (eg. cardiovascular system). Glands (eg. sweat glands, salivary glands, liver) are also formed by epithelial cells.