n. a strip of mesodermal tissue that develops along the dorsal surface of the early embryo, beneath the *neural tube. It becomes almost entirely obliterated by the development of the vertebrae, persisting only as part of the intervertebral discs.
n. the wasting away of a normally developed organ or tissue due to degeneration of cells. This may be physiological or pathological. Physiological atrophy occurs during embryonic life and the neonatal period (web spaces, notochord, umbilical vessels), in adolescence (the thymus), in adult life (the *corpus luteum during the menstrual cycle), and in a variety of organs and tissues in old age. Pathological atrophy may occur through starvation, disuse, denervation, abnormal hormonal stimulation, lack of hormonal stimulation, or ischaemia. Muscular atrophy is associated with various diseases, such as poliomyelitis.... atrophy
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