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Vagus nerve
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Cranial Nerve X Vagus Nerve
Type: mixed.
Function: taste and somatic sensations.
Swallowing, coughing, and voiceproduction. Regulates GI tract and heart
rate.
Injury interferes with swallowing, paralyzes
vocal cords, and causes the heart rate to
increase.
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Vagus nerve ()
components of fibers GVE fibers: originate from dorsal nucleus of
vagus nerve, synapse in parasympatheticganglion, short postganglionic fibers
innervate cardiac muscles, smooth musclesand glands of viscera
SVE fibers: originate from ambiguus, tomuscles of pharynx and larynx
G
VA fibers: carry impulse from viscera inneck, thoracic and abdominal cavity tonucleus of solitary tract
GSA fiber: sensation from auricle, externalacoustic meatus and cerebral dura mater
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Course Exits the skull from jugular foramen
Descends in the neck in carotid sheath between
internal (or common) carotid artery and internal
jugular vein
Right vagus nerve
Enter thoracic inlet on right side of trachea Travels downward posterior to right
brachiocephalic vein and superior vena cava
Passes posterior to right lung root
Forms posterior esophageal plexus
Forms posterior vagal trunk at esophagealhiatus where it leaves thorax and passes into
abdominal cavity, then divides into posterior
gastric and celiac branches
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Left vagus nerve
Enter thoracic inlet between left common
carotid and left subclavian arteries,posterior to left brachiocephalic vein
Crosses aortic arch where left recurrent
laryngeal nerve branches off
Passes posterior to left lung root Forms anterior esophageal plexus
Forms anterior vagal trunk at esophageal
hiatus where it leaves thorax and passes
into abdominal cavity , then divides intoanterior gastric and hepatic branches
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Branches in neck
Superior laryngeal nerve: passesdown side of pharynx and given rise to
Internal branch, which pierces thyrohyoid
membrane to innervates mucous
membrane of larynx above fissure of glottis
External branch, which innervates
cricothyroid
Cervical cardiac branches : descendingto terminate in cardiac plexus
Others: auricular, pharyngeal and
meningeal branches
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Superior laryngeal nerve
External branch
Internal branch
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Branches in thorax
Recurrent laryngeal nerves Right one hooks around right
subclavian artery, left one hooks
aortic arch
Both ascend in tracheo-esophageal
groove
Nerves enter larynx posterior to
cricothyroid joint, the nerve is now
called inferior laryngeal nerve
Innervations: laryngeal mucosa
below fissure of glottis , all laryngeal
laryngeal muscles except
cricothyroid
Bronchial and esophageal branches
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Branches in abdomen Anterior and posterior gastric
branches
Run close to lesser curvatureand innervate anterior andposterior surfaces of stomach
As far as pyloric antrum to fanout into branches in a way likethe digits of a crows foot to
supply pyloric part Hepatic branches: join hepatic
plexus and then supply liver andgallbladder
Celiac branches: sendbranches to celiac plexus to be
distributed with sympatheticfibers to liver, pancreas, spleen,kidneys, intestine as far as leftcolic flexure
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CN10
Vagus Nerves Sensory, motor, or mixed?
Only cranial nerves to extendbeyond head and neck. Fibers emerge from medulla,
leave the skull, and course
downwards into the thorax andabdomen.
Motor Functions: Parasympathetic efferents to
the heart, lungs, and abdominalorgans.
Sensory Functions: Input from thoracic and
abdominal viscera; from baro-and chemoreceptors in thecarotid sinus; from taste buds inposterior tongue and pharynx
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1414--1414
Vagus NerveVagus Nerve
Swallowing,Swallowing,speech,speech,
regulation ofregulation of
visceraviscera Damage causesDamage causes
hoarseness orhoarseness or
loss of voice,loss of voice,
impairedimpaired
swallowing andswallowing and
fatal if both arefatal if both are
cutcut