- Central nervous system- Also known as the command center. It consists of all of the neurons in the brain and spinal cord.
- Peripheral nervous system- Consists of everything outside the brain and spine. (all neurons and nerves outside of the CNS)
2. Autonomic (visceral motor division)- Involved with all involuntary movement and things that we don't typically consciously control. It carries signals to glands and smooth muscle. It has two sub-divisions.
a.) Sympathetic: Energizes us to protect ourselves, kicks in during times of arousal, and is strongly tied to our endocrine system. It arouses the body for action by increasing the heart and respiratory rates in order to increase oxygen supply to the brain and muscles.
b.) Parasympathetic: Keeps heart rate low, blood pressure low and facilitates digestion. It calms the body, slowing down the heartbeat but stimulating digestion.
-Sensory Division (afferent)- sensory nerves carry messages toward the spinal cord and brain from sense organs.
-Motor Division (efferent)- motor nerves carry messages away from the brain and spinal cord to muscles and organs.