Osteocyte - Osteocyte apoptosis and associated pathologies. 1  Osteocytes die as a consequence of senescence, degeneration/necrosis, apoptosis (programmed cell death), and/or osteoclastic engulfment. [1]
Myelin is a substance which encloses the axons of neurons, providing electrical insulation that helps the nervous system function. The importance of this substance is most evident in the types of diseases that develop when it is damaged or destroyed.
It is essential for the proper functioning of the nervous system. It is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination. In humans, myelination begins in the 14th week of fetal development, although little myelin exists in the brain at the time of birth.During infancy, myelination occurs quickly, leading to a child's fast development, including crawling and walking in the first year.yelin is made by different cell types, and varies in chemical composition and configuration, but performs the same insulating function. Myelinated axons are white in appearance, hence the white matter of the brain.