<span> <span>The PNS is divided into a)
somatic and b) autonomic nervous system, and c) the enteric nervous system.
Somatic nerves mediate voluntary movement. The </span>autonomic nervous
system<span>) is the one that
influences the function of </span><span>internal organs,
it</span> <span>is further
subdivided into the </span>sympathetic<span> <span>and the </span></span>parasympathetic<span> <span>nervous systems. The sympathetic nervous system is activated in cases of
emergencies to mobilize energy, while the parasympathetic nervous system is
activated when organisms are in a relaxed state. The </span></span>enteric nervous
system<span> <span>functions to control the </span></span>gastrointestinal<span> <span>system. Both autonomic and enteric nervous systems function
involuntarily. Nerves that exit from the cranium are called </span></span>cranial nerves<span> <span>while those exiting from the spinal cord are called </span></span>spinal nerves<span>.</span></span>