A: The nutritional function of nerve means that neurons synthesize some nutritional factors and release them at their distal ends through axonal transport, which permanently regulates the internal metabolic activities of the dominated tissues and affects their lasting morphological structure, physiological and biochemical changes. Conversely, tissues can also produce nutritional factors to act on nerves. Neurotrophic factors produced by tissues are taken up by nerve endings and transported back to the cell body to play a nutritional role (promoting protein synthesis and the development, growth and survival of neurons), which is a necessary factor for the survival and development of sympathetic nerves and dorsal root ganglia.