Somatic nervous system

The SNS is controlled and monitored by the CNS. The different body segments that connect to certain parts of the spinal cord or brain are called dermatomes. The nerves in the SNS carry both sensory and motor information. All nerves in the SNS are bilateral.

Cranial nerves
Nerves that connect to the brain, coloured blue in the picture.

Spinal nerves
Nerves that connect to the spinal cord. Functionally equivalent to the cranial nerves.

Neurotransmission
The SNS has a single main neurotransmitter, acetylcholine (ACh), whose receptor is the nicotinic ACh receptor (nAChr). When ACh binds to it, the channel opens, allowing depolarization of the muscle fiber of the skeletal muscle.