The nervous system has several key functions including controlling the respiratory center and relaying information about stimuli like pain, hunger, and full bladders. The nervous system is made up of nerve cells called neurons that receive, interpret, and respond to information. Neurons have dendrites that receive stimuli, an axon that carries impulses, and a nucleus. Neuroglia provide protection and nourishment to neurons but do not transmit impulses. The central nervous system includes the brain and spinal cord while the peripheral nervous system includes cranial nerves, spinal nerves, and peripheral nerves.