What are the four different nervous systems?

There are three main divisions or components of the Nervous System:

1. The Central Nervous System (CNS) consists of the brain and spinal cord. The brain is the center or control of the entire body and the spinal cord is the two-way communication channel that carries messages to and from the brain.**

2. The Peripheral Nervous System (PNS) consists of the cranial nerves and the spinal nerves. The cranial nerves are the 12 pairs of nerves that emerge from the brain, and the spinal nerves are the 31 pairs of nerves that emerge from the spinal cord.**

3. The Enteric Nervous System (ENS) is a division of the Peripheral Nervous System that consists of the nerves and nerve cells that control the digestive tract. It is considered "semi-autonomous" meaning it can function on its own but is also able to receive information from and send information to the Central Nervous System.**