Terminal | Purely sensory | Lamina terminalis | Septal nuclei | Involved in the detection of pheromones.[10][unreliable medical source?] | |
I | Olfactory | Purely sensory | Telencephalon | Anterior olfactory nucleus | Transmits the sense of smell from the nasal cavity.[11] Located in the olfactory foramina in the cribriform plate of the ethmoid bone. |
II | Optic | Sensory | Retinal ganglion cells | Lateral geniculate nucleus[12] | Transmits visual signals from the retina of the eye to the brain.[13] Located in theoptic canal. |
III | Oculomotor | Mainly motor | Anterior aspect of Midbrain | Oculomotor nucleus, Edinger-Westphal nucleus | Innervates the levator palpebrae superioris, superior rectus,medial rectus, inferior rectus, and inferior oblique, which collectively perform most eye movements. Also innervates the sphincter pupillae and the muscles of the ciliary body. Located in the superior orbital fissure. |
IV | Trochlear | motor | Dorsal aspect of Midbrain | Trochlear nucleus | Innervates the superior oblique muscle, which depresses, rotates laterally, and intorts the eyeball. Located in the superior orbital fissure. |
V | Trigeminal | Both sensory and motor | Pons | Principal sensory trigeminal nucleus, Spinal trigeminal nucleus,Mesencephalic trigeminal nucleus, Trigeminal motor nucleus | Receives sensation from the face and innervates the muscles of mastication.
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VI | Abducens | Mainly motor | Nuclei lying under the floor of the fourth ventricle Pons | Abducens nucleus | Innervates the lateral rectus, which abducts the eye. Located in the superior orbital fissure. |
VII | Facial | Both sensory and motor | Pons (cerebellopontine angle) above olive | Facial nucleus, Solitary nucleus,Superior salivary nucleus | Provides motor innervation to themuscles of facial expression, posterior belly of the digastric muscle,stylohyoidmuscle, andstapedius muscle. Also receives the special sense of taste from the anterior 2/3 of the tongue and provides secretomotorinnervation to the salivary glands (except parotid) and the lacrimal gland. Located in and runs through the internal acoustic canal to the facial canal and exits at thestylomastoid foramen. |
VIII | Vestibulocochlear (also auditory,[14] acoustic,[14] or auditory-vestibular) | Mostly sensory | Lateral to CN VII (cerebellopontine angle) | Vestibular nuclei, Cochlear nuclei | Mediates sensation of sound, rotation, and gravity (essential for balance and movement). More specifically, the vestibular branch carries impulses for equilibrium and the cochlear branch carries impulses for hearing. Located in the internal acoustic canal. |
IX | Glossopharyngeal | Both sensory and motor | Medulla | Nucleus ambiguus, Inferior salivary nucleus, Solitary nucleus | Receives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the stylopharyngeus. Some sensation is also relayed to the brain from the palatine tonsils. Located in the jugular foramen. |
X | Vagus | Both sensory and motor | Posterolateral sulcus of Medulla | Nucleus ambiguus, Dorsal motor vagal nucleus, Solitary nucleus | Supplies branchiomotorinnervation to most laryngeal and pharyngeal muscles (except the stylopharyngeus, which is innervated by the glossopharyngeal). Also provides parasympathetic fibers to nearly all thoracic and abdominal viscera down to the splenic flexure. Receives the special sense of taste from the epiglottis. A major function: controls muscles for voice and resonance and the soft palate. Symptoms of damage:dysphagia (swallowing problems),velopharyngeal insufficiency. Located in the jugular foramen. |
XI | Accessory Sometimes: cranial accessory spinal accessory | Mainly motor | Cranial and Spinal Roots | Nucleus ambiguus, Spinal accessory nucleus | Controls the sternocleidomastoid and trapezius muscles, and overlaps with functions of the vagus nerve (CN X). Symptoms of damage: inability to shrug, weak head movement. Located in the jugular foramen. |
XII | Hypoglossal | Mainly motor | Medulla | Hypoglossal nucleus | Provides motor innervation to the muscles of the tongue (except for the palatoglossal muscle, which is innervated by the vagus nerve) and other glossal muscles. Important for swallowing (bolus formation) and speech articulation. Passes through the hypoglossal canal. |
Wednesday, February 26, 2014
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