Question: where are neurons found in the human body

title: Neuron
text: Although most injury responses include a calcium influx signaling to promote resealing of severed parts , axonal injuries initially lead to acute axonal degeneration , which is rapid separation of the proximal and distal ends within 30 minutes of injury . Degeneration follows with swelling of the axolemma , and eventually leads to bead like formation . Granular disintegration of the axonal cytoskeleton and inner organelles occurs after axolemma degradation . Early changes include accumulation of mitochondria in the paranodal regions at the site of injury . Endoplasmic reticulum degrades and mitochondria swell up and eventually disintegrate . The disintegration is dependent on ubiquitin and calpain proteases ( caused by influx of calcium ion ) , suggesting that axonal degeneration is an active process . Thus the axon undergoes complete fragmentation . The process takes about roughly 24 hrs in the peripheral nervous system ( PNS ) , and longer in the CNS . The signaling pathways leading to axolemma degeneration are currently unknown .