What part of the nervous system sends signals to the muscles that are voluntarily controlled?

1 Answer
Oct 15, 2017

The somatic nervous system


The nervous system can be divided into two main parts:

  • Central nervous system (CNS) - brain and spinal cord
  • Peripheral nervous system (PNS) - contains motor neurons and sensory neurons outside of the CNS

The motor neurons of the PNS are efferent (sending signals from the CNS to the body) and can be divided into:

  • Somatic - controls VOLUNTARY movement
    Ex: flexing your arm, nodding your head, etc.

  • Autonomic - controls INVOLUNTARY actions
    Ex: increasing/decreasing your heart rate, contracting/dilating your pupils

Note: the autonomic nervous system can be further categorized by the sympathetic and parasympathetic divisions, which typically have opposite effects on the same targets (Ex: pupil constriction is a parasympathetic activity, pupil dilation is a sympathetic activity)

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