PSL300H1 Lecture Notes - Peripheral Nervous System, Axoplasmic Transport, Myelin
Document Summary
Consists of the brain and the spinal chord. Neurons outside the cns make up the peripheral nervous system. The pns includes neurons entirely outside the cns, and also parts of neurons. The pns comprises the somatic nervous system, for controlling voluntary action that project into or out of the cns via the skeletal muscle controls digestion and movements of the intestines. Part of the autonomic nervous system is the enteric nervous system, which. Receives lots of input from the spinal chord, but can also operate o independently of the cns. Most of the body"s neurons are in the cns. Brain has ~86 billion neurons and spinal chord has about 1 billion. Estimates for the enteric nervous system range from 100-600 million and the total for the pns is probably not much more neurons, and are likely about as numerous. Most of the neurons in the brain are in the cerebellum only 10% in cerebrum.
