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:: Major Organs and Divisions of the Nervous System - Expanded View ::
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The nervous system is anatomically and functionally partitioned into the central nervous system and peripheral nervous system.

Making up the centeral nervous system (CNS) are the brain and spinal cord, which serve as the body's assessment and control center. These vital organs are surrounded and protected by the skull and vertebral column.

The peripheral nervous system (PNS) is formed by a network of nerves that extend throughout the body.
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The nerves connect to the central nervous system via 12 pairs of cranial nerves and 31 pairs of spinal nerves.

Inside the nerves are the axon processes of numerous nerves cells (or neurons). The wire-like axons run the length of the nerves and are grouped by connective tissue into cylindrical bundles called fascicles (L. fasciculi).

Sensory neuron axons conduct impulses from the peripheral organs to the CNS and motor neuron axons conduct impulses from the CNS to the peripheral organs.
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Most nerves are mixed, meaning they contain bot3 motor and senory neurons.

Based on their functions, the neurons in nerves divide the peripheral nervous system into somatic and autonomic nervous systems.

Somatic neurons carry signals that allow the CNS to consciously monitor the external environment and control body movements. In contrast, autonomic neurons carry signals that allow the CNS to subconsciously regulate the body's internal environment and control the activity of the soft organs (viscera).
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The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS).  The CNS is formed by the brain and spinal cord, and the PNS is formed by a network of nerves.