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Encyclopedia > Cochlear nerve

The Cochlear nerve (n. cochlearis) is one of the two branches of the Vestibulocochlear nerve (the Vestibular nerve is the other.) The vestibulocochlear nerve is the eighth of twelve cranial nerves, and also known as the auditory nerve. ...


The cochlear nerve arises from cells in the spiral ganglion of the cochlea. The peripheral fibers pass on to the hair cells of the cochlea, and the central fibers course through the canal of the modiolus and continue to the internal auditory meatus.


Axons of the cochlear nerve synapse in the cochlear nucleus. Cells in the ventral cochlear nucleus then synapse on cells of the superior olives (superior olivary complex) of the pons on the same side and on the opposite side. These cells compare the timing of impulses from the left and right ears, allowing for auditory localization. Superior olive cells' axons form part of a fibre tract, the lateral lemniscus, and go to the inferior colliculus in the tectum. Cells in the dorsal cochlear nucleus send axons directly via the trapezoid bodies and lateral lemniscus to the inferior colliculus. Dorsal cochlear nucleus cells carry information about the frequency of sounds. Axons of the inferior colliculus synapse on the medial geniculate nucleus of the thalamus on the same side and on the opposite side. Axons of medial geniculate neucleus cells project to the primary auditory cortex, also known as A1. Illustration of the major elements in a prototypical synapse. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... The lateral lemniscus is a tract of axons in the brainstem that carries information about sound to the inferior colliculus of the midbrain. ... The paired inferior colliculi together with the superior colliculi form the eminences of the corpora quadrigemina. ... The medial geniculate nucleus is a nucleus of the thalamus that acts as a relay for auditory information. ... The thalamus is a part of the brain. ... The primary auditory cortex the region of the brain which is responsible for processing of auditory (sound) information. ... The primary auditory cortex the region of the brain which is responsible for processing of auditory (sound) information. ...


Some reflex fibers pass on to the motor nuclei of the eye musculature and other motor nerve nuclei of cranial and spinal nerves via the tectospinal and tectobulbar tracts.


See also

Illustration of a cochlear implant Cochlear implants are hearing devices that can help people with certain kinds of hearing impairment or who have a severe to profound hearing loss. ...

External links

  • Penn State
  • Illustration
  • Illustration
  • Gray's
Major nerves (also see Peripheral nervous system)

Cranial nerves: I olfactory | II optic | III oculomotor | IV trochlear | V trigeminal (V1 ophthalmic - supraorbital, V2 maxillary - sphenopalatine ganglion, V3 mandibular - auriculotemporal - buccal - inferior alveolar ) | VI abducens | VII facial | VIII vestibulocochlear (cochlear, vestibular) | IX glossopharyngeal | X vagus (recurrent laryngeal) | XI accessory | XII hypoglossal    Nerves redirects here. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... Cranial nerves are nerves which emerge from the brainstem instead of the spinal cord. ... The olfactory nerve is the first of twelve cranial nerves. ... The optic nerve is the nerve that transmits visual information from the retina to the brain. ... The oculomotor nerve () is the third of twelve paired cranial nerves. ... The fourth of twelve cranial nerves, the trochlear nerve controls the function of the superior oblique muscle, which rotates the eye towards the nose and also moves the eye downward. ... The trigeminal nerve is the fifth (V) cranial nerve, and carries sensory information from most of the face, as well as motor supply to the muscles of mastication (the muscles enabling chewing), tensor tympani (in the middle ear) and other muscles in the floor of the mouth, such as the... The supraorbital nerve arises from the orbit by the supraorbital foramen and supplies the upper eyelid and forehead integuments. ... The mandibular nerve is the third branch (V3) of the trigeminal nerve. ... The auriculotemporal nerve is a branch of the mandibular nerve (Viii) and supplies motor fibres to the temporomandibular joint and parasympathetic fibres to the parotid glands. ... A branch of the mandibular nerve (which is itself a branch of the trigeminal nerve), the buccal nerve transmits sensory information from skin over the buccal membrane (in general, the cheek) and from the second and third molar teeth. ... The inferior alveolar nerve is a branch of the mandibular nerve, which is itself the third branch (V3) of the fifth cranial nerve, the trigeminal nerve (cranial nerve V). ... The sixth out of twelve cranial nerves, the abducens nerve controls the lateral rectus muscle - this means that the action of this nerve controls each eyes ability to look laterally (away from the midline). ... The facial nerve is seventh of twelve paired cranial nerves. ... The vestibulocochlear nerve is the eighth of twelve cranial nerves, and also known as the auditory nerve. ... The glossopharyngeal nerve is the ninth of twelve cranial nerves. ... The vagus nerve is tenth of twelve paired cranial nerves and is the only nerve that starts in the brainstem (somewhere in the medulla oblongata) and extends all the way down past the head, right down to the abdomen. ... The recurrent laryngeal nerve is a branch of the vagus nerve (the tenth cranial nerve) which supplies motor function and sensation to the larynx (voice box). ... The accessory nerve is the eleventh of twelve cranial nerves. ... The hypoglossal nerve is the twelfth cranial nerve. ...


Spinal nerves C2-C5: greater occipital, lesser occipital, greater auricular, lesser auricular, phrenic The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ... The greater occipital nerve is a spinal nerve arising between the first and second cervical vertebrae, along with the lesser occipital nerve. ... The lesser occipital nerve is a spinal nerve arising between the first and second cervical vertebrae, along with the greater occipital nerve. ... The greater auricular nerve originates from the cervical plexus, composed of branches of spinal nerves C2 and C3. ... The lesser auricular nerve originates from the cervical plexus, composed of branches of spinal nerves C2 and C3. ... The phrenic nerve arises from spinal nerves C3, C4 and C5. ...


Spinal nerves C5-T1 (brachial plexus) --- before forming cords (dorsal scapular, long thoracic, suprascapular) --- lateral cord (musculocutaneous, median) --- posterior cord (axillary, radial) --- medial cord (median, ulnar) The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ... The brachial plexus is an arrangement of nerve fibres (a plexus) running from the spine (vertebrae C5-T1), through the neck, the axilla (armpit region), and into the arm. ... The dorsal scapular nerve arises from the brachial plexus, specifically from spinal nerves C4 and C5. ... The long thoracic nerve supplies motor innervation to the serratus anterior muscle. ... The Nervus suprascapularis (Suprascapular nerve) is a nerve of the plexus brachialis. ... The major end branch of the lateral cord, courses inferiorly within the anterior arm, supplying motor fibers to the arm muscles that flex the forearm (the biceps brachii and brachialis). ... Diagram from Grays anatomy, depicting the peripheral nerves of the upper extremity, amongst others the median nerve The median nerve is a nerve that runs down the arm and forearm. ... The axillary nerve is a nerve of the human body, that comes off the posterior cord of the brachial plexus at the level of the axilla (armpit). ... The radial nerve is a nerve in the human body, that supplies the arm, the forearm and the hand. ... Diagram from Grays anatomy, depicting the peripheral nerves of the upper extremity, amongst others the median nerve The median nerve is a nerve that runs down the arm and forearm. ... The ulnar nerve is a nerve that in humans runs down the arm and forearm, and into the hand. ...


Spinal nerves T2-S5: intercostal | sacral plexus | sciatic (tibial, common peroneal) | pudendal The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ... The sciatic nerve is a large nerve that runs down the lower limb. ... The Tibial Nerve The tibial nerve passes through the popliteal fossa to pass below the arch of soleus. ... The pudendal nerve is responsible for orgasm, urination, and defecation in both sexes. ...


  Results from FactBites:
 
Acoustic Neuroma: Encyclopedia of Medicine (2815 words)
An acoustic neuroma is a benign tumor involving cells of the myelin sheath that surrounds the vestibulocochlear nerve (eighth cranial nerve).
The vestibulocochlear nerve extends from the inner ear to the brain and is made up of a vestibular branch, often called the vestibular nerve, and a cochlear branch, called the cochlear nerve.
A unilateral tumor is a tumor arising from one nerve and a bilateral tumor arises from both vestibular nerves.
  More results at FactBites »

 
 

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