cranial nerves are part of the cns ( cns ) or pns.
are cranial nerves part of the cns or pns?
cns )
the nervous system is a highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. the nervous system detects environmental changes that impact the body, then works in tandem with the endocrine system to respond to such events. nervous tissue first arose in wormlike organisms about 550 to 600 million years ago. in vertebrates it consists of two main parts, the central nervous system (cns) and the peripheral nervous system (pns). the cns consists of the brain and spinal cord. the pns consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the cns to every other part of the body. nerves that transmit signals from the brain are called "motor" or "efferent" nerves, while those nerves that transmit information from the body to the cns are called "sensory" or "afferent". spinal nerves serve both functions and are called "mixed" nerves. the pns is divided into three separate subsystems, the somatic, autonomic, and enteric nervous systems. somatic nerves mediate voluntary movement. the autonomic nervous system is further subdivided into the sympathetic and the parasympathetic 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 enteric nervous system functions to control the gastrointestinal system. both autonomic and enteric nervous systems function involuntarily. nerves that exit from the cranium are called cranial nerves while those exiting from the spinal cord are called spinal nerves.
nervous system
cranial nerves





















































cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord). ten of the cranial nerves originate in the brainstem. cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck.
cranial nerves