Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines. The commonly used abbreviation for gastrointestinal is GI. (Outside of medicine, GI can also stand for galvanized iron, general issue or government issue-as in GI Joe).
Before the extracellular matrix is calcified, the tissue is called osteoid (bone-like) tissue. When the concentrations of calcium and phosphate ions rise high enough, they are deposited into the extracellular matrix, and the bone calcifies.
An osteocyte, a star-shaped type of bone cell, is the most commonly found cell in mature bone tissue, and can live as long as the organism itself. The adult human body has about 42 billion osteocytes. Osteocytes have an average half life of 25 years, they do not divide, and they are derived from osteoprogenitors, some of which differentiate into active osteoblasts. Osteoblasts/osteocytes develop in mesenchyme. In mature bone, osteocytes and their processes reside inside spaces called lacunae and