Nervous Systems

The nervous system can be separated into parts based on structure and on function:

Structurally, it can be divided into

1. Central nervous system (CNS) and
2. Peripheral nervous system (PNS)

Functionally, it can be divided into

1. Somatic and
2. Visceral

The CNS is composed of the brain and spinal cord, both of which develop from the neural tube in the embryo.

The PNS is composed of all nervous structures outside the CNS that connect the CNS to the body.

Elements of this system develop from neural crest cells and as outgrowths of the CNS. The PNS consists of the spinal and cranial nerves, visceral nerves and plexuses, and the enteric system.