8/14/2019 The Peripheral Nervous System or PNS, Is

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The peripheral nervous system or PNS, is part of the nervoussystem, and consists of the nerves and neurons that reside or extend outside the central nervous system (the

brain and spinal cord ) to serve the limbs and organs, for example. Unlike the central nervous system,however, the PNS is not protected by bone or the blood-brain barrier , leaving it exposed to toxins andmechanical injuries. The peripheral nervous system is divided into the somatic nervous system and theautonomic nervous system .

I Olfactory nerve Anterior olfactory nucleus Transmits the sense of smell

II Optic nerve Lateral geniculate nucleus Transmits visual information to the brain

III Oculomotor nerve Oculomotor nucleus ,Edinger-Westphal nucleus

Innervates the superior rectus, medial rectus,inferior rectus, and inferior oblique, whichcollectively perform most eye movements

IV Trochlear nerve Trochlear nucleusInnervates the superior oblique muscle, whichdepresses, pulls laterally, and intorts theeyeball

V Trigeminal nerve

Principal sensory trigeminalnucleus , Spinal trigeminalnucleus , Mesencephalictrigeminal nucleus, Trigeminal motor nucleus

Receives sensation from the face and

innervates the muscles of mastication

VI Abducent nerve (or abducens nerve ) Abducens nucleus Innervates the lateral rectus, which abducts

the eye

VII Facial nerve Facial nucleus, Solitary Provides motor innervation to the muscles of

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nucleus , Superior salivarynucleus

facial expression and stapedius, receives thespecial sense of taste from the anterior two-thirds of the tongue, and providessecretomotor innervation to the salivary glands(except parotid) and the lacrimal gland

VIIIVestibulocochlear nerve(or auditory-vestibular nerve )

Vestibular nuclei , Cochlear nuclei

Senses sound, rotation and gravity (essentialfor balance & movement)

IX Glossopharyngeal nerveNucleus ambiguus , Inferior salivary nucleus , Solitarynucleus

Receives taste from the posterior 1/3 of thetongue, provides secretomotor innervation tothe parotid gland, and provides motor innervation to the stylopharyngeus

X Vagus nerve Nucleus ambiguus , Dorsalmotor vagal nucleus, Solitarynucleus

Supplies branchiomotor innervation to mostlaryngeal and pharyngeal muscles; providesparasympathetic fibers to nearly all thoracicand abdominal viscera down to the splenicflexure; and receives the special sense of tastefrom the epiglottis

XIAccessory nerve (or cranial accessory nerve or spinal accessory nerve )

Nucleus ambiguus , Spinalaccessory nucleus

Controls muscles of the neck and overlapswith functions of the vagus

XII Hypoglossal nerve Hypoglossal nucleusProvides motor innervation to the intrinsicmuscles of the tongue and other glossalmuscles

The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal andventral roots that come out of the spinal cord. The spinal nerve is the bit that passes out of thevertebrae through the intervertebral foramen.

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