The Nervous System
The nervous system allows us to interpret and respond to our environment. In this way, the nervous system is similar to a computer (but much more complex). There are inputs (sensory organs), processors (brain), memory (brain), and outputs (motor nerves). Information about our internal and external environments is detected by our sensory organs and sent to the spinal cord. These signals travel to the brain and are processed and integrated. Once processed, these signals then move back down the spinal cord where they eventually make contact with our muscles, blood vessels, and other organs.
Divisions of the Nervous System
The nervous system in humans can be divided into two major (2) components: The Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS contains the brain and spinal cord while the PNS contains everything outside or “peripheral” to the CNS, including the autonomic nervous system. The autonomic nervous system is termed “autonomic” because it is beyond our voluntary control. That is, the autonomic nervous system works “automatically.”
The autonomic nervous system is further divided into three components: the sympathetic, the parasympathetic, and the enteric (gut) nervous systems. Each of these will be discussed later.
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