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.
The myelin sheath allows signals to be transmitted rapidly from the nervous system to the rest of the body. When myelin is destroyed -- called demyelination -- nerve signals are slowed or stopped. In the central nervous system -- the brain and spinal cord -- myelin cannot repair itself after it is damaged.However, in the peripheral nervous system -- the nerves that travel to the arms and legs -- myelin can often regrow. A number of diseases affect the myelin sheath in the central and peripheral nervous system.owever, in the peripheral nervous system -- the nerves that travel to the arms and legs -- myelin can often regrow. A number of diseases affect the myelin sheath in the central and peripheral nervous system.