Artificial organ a stationary power supply or other stationary resources such as filters or chemical processing units. (Periodic rapid recharging of batteries, refilling of chemicals, and/or cleaning/replacing of filters would exclude a device from being called an artificial organ.) Thus, a dialysis machine, while a very successful and critically important life support device that almost completely replaces the duties of a kidney, is not an artificial organ. Constructing and installing artificial organs, an extremely research-intensive and expensive process initially, may entail many years of ongoing maintenance services not needed by a natural organ.: The use of any artificial organ by humans is
Wallerian degeneration PNS. Another factor that affects degradation rate is the diameter of the axon: larger axons require a longer time for the cytoskeleton to degrade and thus take a longer time to degenerate. Myelin is a phospholipid membrane that wraps around axons to provide them with insulation. It is produced by Schwann cells in the PNS, and by oligodendrocytes in the CNS. Myelin clearance is the next step in Wallerian degeneration following axonal degeneration. The cleaning up of myelin debris is different for PNS and CNS. PNS is much faster and efficient at clearing myelin debris in comparison to CNS, and