By measuring telomeres, some scientists believe they can determine biological age, which doesn't always equal chronological age. That means some people may be biologically older or younger than their age, said Jerry Shay, professor and vice chairman of cell biology at UT Southwestern Medical Center in Dallas.
It is of ectodermal origin and is continuous with the skin at various body openings such as the eyes, ears, nose and mouth, the urethral opening and the anus. Some mucous membranes secrete mucus, a thick protective fluid. The function of the membrane is to stop pathogens and dirt from entering the body and to prevent bodily tissues from becoming dehydrated.
A layer of mucus along the inner walls of the stomach is vital to protect the cell linings of that organ from the highly acidic environment within it. Mucus is not digested in the intestinal tract. Mucus is also secreted from glands within the rectum due to stimulation of the mucous membrane within.