Neurons are extremely long-lived. As long as they are not damaged by disease or trauma, they can last a lifetime. Neurons have a high metabolic rate, requiring a continuous and abundant supply of oxygen and glucose. Neurons have limited powers of regeneration. If the cell body of a neuron is destroyed, that neuron can not be replaced.
Mature neurons are incapable of cell division.
16.2 Neurons have a main CELL BODY, which is 5-140 micrometers in diameter. The cell body contains the nucleus, mitochondria and other cellular organelles. The AXON is a single long, thin process that conducts nerve impulses AWAY from the cell body to another neuron, muscle cell or gland cell. Axons vary in length from a few millimeters to a meter or more. There can be 10,000 or more axon terminals per neuron.