Flashcards in Intro to Cranial Nerves Deck (73):
Which cranial nerves are associated with the midbrain?
CN III (oculomotor)
CN IV (trochlear)
Which cranial nerves are associated with the pons?
CN V (trigeminal)
CN VI (abducens)
CN VII (facial)
CN VIII (vestibulocochlear)
What cranial nerves are associated with the medulla oblongata?
CN IX (glossopharyngeal)
CN X (vagus)
CN XI (accessory)
CN XII (hypoglossal)
Which cranial nerves contain preganglionic parasympathetic fibers?
Cranial nerves III, VII, IX, and X
(oculomotor, facial, glossopharyngeal, vagus)
What 4 cranial nerve ganglia contain the cell bodies of general sensory neurons?
Which 3 cranial nerve ganglia contain the cell bodies of taste in addition to general sensation?
Where are the cell bodies of motor neurons (Multipolar)
In separate and discrete units called nuclei within the brainstem, which are special clusters of multipolar neurons)
What are the 5 branchiomeic cranial nerves?
Accessory nerve (XI)
What innervates structures derived from branchial arch 1? Branchial arch 2? Branchial arch 3?
Trigeminal (V) = branchial arch 1
Facial (VII) = branchial arch 2
Glossopharyngeal (IX) = branchial arch 3
What innervates structures derived from branchial arch 4-6? Branchial arch beyond 6 if present?
Vagus (X) = branchial arch 4-6
Accessory (XI) = brachial arch beyond 6
What is the name of the fibers that innervate skeletal muscles derived from somites and innervated by spinal nerves and some cranial nerves to provide motor efferent?
What is the name of fibers that innervate skeletal muscle derived from branchial arches and innervated by some of the cranial nerves?
Somatic motor fibers innervate skeletal muscles derived from somites
Branchial motor fibers innervate skeletal muscle derived from brachial arches
For CN III (oculomotor) and the parasympathetic fibers, where are the preganglionic fibers, the postganglionic fibers, and what is their target structure?
Preganglionic: Parasympathetic (motor) root of ciliary ganglion
Postganglionic: Ciliary ganglion
Targets the ciliary muscle and the spincter of the pupil
For CN VII (facial) and the parasympathetic fibers,
1. what is the name of the portion of the nerve that contains parasympathetic fibers?
2. what are the 2 parts of this nerve containing preganglionic fibers?
3. what are the names of the ganglion containing postganglionic fibers?
4. what are the target structures for each part?
1. The preganglionic parasymp. fibers are contained in the nervus intermedius portion of the facial nerve
2. Splits into the greater petrosal nerve and the chorda tympani
3. Greater petrosal nerve's postganglionic fibers are in the pterygopalatine ganglion. Chorda tympani postganglionic fibers are int he submandibular ganglion
4. Greater petrosal nerve targets the lacrimal gland, nasal gland, and palatine glands. Chorda tympani targets the submandibular gland, sublingual gland, lingual glands
For CN IX (glossopharyngeal) and the parasympathetic fibers, what nerve contains the preganglionic fibers, which ganglion contains the postganglionic fibers, and what is their target structure?
Lesser petrosal nerve contains the preganglionic fibers, otic ganglion contains the postganglionic fibers, and targets the parotid gland
Where are the sensory neurons for the olfactory nerve located? What are they located in?
The specialized bipolar cells are located in olfactory mucosa on the superior part of the superior nasal concha and superior part of the nasal septum
Which bone do the olfactory nerves proceed through?
Proceed through the cribriform plate of the ethmoid bone
Where does the optic nerve travel through? With what other vessel?
Travels through the optic canal with the ophthalmic artery
What types are fibers are contained within CN III (oculomotor)?
Somatic motor fibers and parasympathetic fibers
Describe the course of the oculomotor nerve before dividing into two divisions.
Emerges from ventral aspect of the midbrain, proceeds through the lateral walls of the cavernous sinus, and enters orbit through the superior orbital fissure
What two divisions make up the oculomotor nerve? What muscles do they innervate?**
The superior division innervates the levator palpebrae superioris muscle and the superior rectus eye muscle
The inferior division innervates the medial rectus eye muscle, the inferior rectus eye muscle, and the inferior oblique eye muscle
What are the only two ocular muscles not supplied by CN III (oculomotor)?**
The superior oblique (IV) and the lateral rectus (VI)
Which division of the oculomotor nerve do the preganglionic parasympathetic fibers travel with until departing as the _____?
Preganglionic parasympathetic fibers travel in the inferior division of the oculomotor nerve until separating as the parasympthetic (Motor) root of the ciliary ganglion
Where do the preganglionic parasympathetic fibers of the ciliary ganglion synapse with postganglionic fibers?
In the cililary ganglion
Within what nerves do postganglionic parasympathetic fibers of the oculomotor nerve leave the ganglion, and what do they innervate?
Leave the ganglion as short ciliary nerves, go to the eyeball where they supply the ciliary muscle and sphincter of the pupil
What do the ciliary muscle and the sphincter of the pupil do? What is the antagonist of the sphincter of the pupil and where does it receive its innervation?
The ciliary muscle is involved in accommodation of the lens for near vision.
The sphincter of the pupil controls the amount of light entering the eye. Its actions are opposed by the dilator of the pupil, which receives sympathetic innervation from the superior cervical ganglion.
Where does the trochlear (CN IV) nerve emerge from, describe its path and which muscle of the eye it innervates.**
Trochlear nerve emerges from the dorsal aspect of the midbrain, passes through the lateral wall of the cavernous sinus and enters orbit through the superior orbital fissure. Supplies the superior oblique eye muscle
What is the course of the abducens nerve (CN VI) and which eye muscle does it supply?**
Passes through cavernous sinus and enters orbit through the superior orbital fissure. Supplies the lateral rectus eye muscle
What does the vestibulocochlear (VIII) nerve enter to pass into the petrous portion of the temporal bone?
The internal acoustic meatus
What types of nerves are contained in the glossopharyngeal nerve (CN IX)?
Contains motor, sensory (mixed) as well as preganglionic parasympathetic fibers
Which branchial arch is supplied by the glossopharyngeal nerve (CN IX)?
Branchial arch 3
Where on the brainstem does the glossopharyngeal nerve emerge?
From the medulla in the post olivary sulcus (sits posterior to the olives)
Which two ganglia do the sensory fibers of CN IX (glossopharyngeal) emerge from?
The superior and inferior ganglia located in the jugular foramen
Which 3 cranial nerves exit the skull through the jugular foramen?
CN IX, X, and XI
(glossopharyngeal, vagus, accessory)
What are the major branches of the glossopharyngeal nerve?
Motor branch to stylopharyngeus muscle
Pharyngeal and tonsillar branches
What fibers are contained within the tympanic branch of the glossopharyngeal nerve?
1. All of the preganglionic parasympathetic fibers of the glossopharyngeal nerve
2. Sensory fibers of the tympanic cavity
What do the preganglionic parasympathetic fibers of the glossopharyngeal nerve converge as? Where does it pass out of the petrous part of the temporal bone, and what passes out of the same area near it.
The preganglionic parasympathetic fibers of the glossopharyngeal nerve converge as the lesser petrosal nerve, which passes out of the petrous part of the temporal bone via the hiatus of the lesser petrosal nerve. This is right next to the greater petrosal nerve of CN VII (facial)
Through which foramen does the lesser petrosal nerve exit the skull? Where does it enter once it leaves?
Leaves the skull through the foramen ovale and enters the infratemporal fossa.
What ganglia do the preganglionic parasympathetic fibers synapse with (the preganglionic parasympathetic fibers of the tympanic branch of the glossopharyngeal nerve)?
In the otic ganglion with postganglionic parasympathetic neurons
What nerve does the postganglionic parasympathetic fibers (of the tympanic branch of the glossopharyngeal nerve) join with and which gland are they distributed to?
The postganglionic parasympathetic fibers join with the auriculotemporal nerve (V3) and are distributed to the parotid gland
What branch of the glossopharyngeal nerve carries sensory fibers from baroreceptors in the carotid sinus and chemoreceptors in the carotid body?
What is the only muscle innervated by the glossopharyngeal nerve?
The stylopharyngeus muscle (motor branch of the glossopharyngeal nerve)
What branches of glossopharyngeal are responsible for general sensation from the mucous membrane and the pharynx and palatine tonsils?
The pharyngeal and tonsillar branches
What branch of the glossopharyngeal are responsible for general sensation of posterior 1/3 of tongue and the taste fibers for posterior 1/3 of tongue?
The lingual branch (Lingula = tongue)
What do lesions of the glossopharyngeal nerve manifest as?
Testing of the afferent limb of the gag reflex (stroking posterior 1/3 of tongue with a spatula) [efferent is vagus]
Testing taste on the posterior 1/3 of tongue
Pain is referred to the middle ear by someone with tonsillitis is because glossopharyngeal supplies tonsillar region and mucous membrane of middle ear
What branchial arches are supplied by the vagus nerve?
Branchial arch 4, 5, and 6
What nerve fibers are contained in the vagus nerve?
Sensory and motor nerves (mixed) and contains preganglionic parasympathetic fibers
Which part of the brainstem does the vagus nerve emerge from?
Emerges from the medulla oblongata from the post-olivary sulcus
Where does the vagus leave the skull?
Through the jugular foramen (along with glossopharyngeal and the accessory nerves)
Where do the sensory fibers of the vagus nerve originate from?
Originate from the superior and inferior ganglia in the jugular foramen
What are the 8 major branches of the vagus nerve?
1. Meningeal branch
2. Auricular branch
3. Pharyngeal branch
4. Carotid branch
5. Aortic branch
6. Superior laryngeal branch
7. Recurrent laryngeal nerves
8. Vagal branches below recurrent laryngeal nerves
Which branch of the vagus contributes to sensory supply of dura mater in the posterior cranial fossa?
What does the auricular branch supply?
Supplies the external auditory meatus and external surface of tympanic membrane
If you irritate the auricular branch, what may happen?
May initiate a cough reflex or nausea
Which branch is the main motor nerve to the pharynx? What are the only muscles of the pharynx not supplied by this branch? What is the only part of the palate that this nerve does not supply?
The pharyngeal branch of the vagus nerve.
Only the stylopharyngeus muscle is not supplied by the vagus (stylopharyngeus is supplied by glossopharyngeal)
Only the tensor of the palate is not supplied by the vagus (is supplied by V3)
What makes up the pharyngeal plexus? What do the sensory fibers of this plexus supply?
The pharyngeal plexus is made of:
Pharyngeal branch of vagus
Pharyngeal branch of glossopharyngeal
Postganglionic sympathetic fibers from the superior cervical ganglion
The sensory fibers of the pharyngeal branch supply part of the mucosa of the pharynx
What branch of the vagus carries sensory fibers from the baroreceptors in the carotid sinus and chemoreceptors in the carotid body? What branch of the vagus carries sensory fibers from the aortic baroreceptors in the aortic arch and chemoreceptors in the aortic body?
The carotid branch carries sensory fibers from the baroreceptors in carotid sinus and chemoreceptors in carotid body
The aortic branch carries sensory fibers from the baroreceptors in the aortic arch and chemoreceptors in aortic body
What are the two branches of the superior laryngeal branch of the vagus nerve?
The internal laryngeal branch (sensory)
The external laryngeal branch (motor)
What does the internal laryngeal branch of the superior laryngeal branch of the vagus pierce, and what does it supply? What kind of sensory fibers do they contain?***
The internal laryngeal nerve pierces the thyrohyoid membrane and supplies lining of larynx as far as vocal cords. Also sends branches to the valleculae of tongue and the epiglottis (the fibers that get sent here contain taste fibers)
What does the external laryngeal branch of the superior laryngeal branch of the vagus nerve supply?
Supplies the cricotyroid muscle and cricopharyngeus portion of the inferior constrictor
What are all the nerves that supply the intrinsic muscles of the larynx?
The two branches of the superior laryngeal branch:
-Internal laryngeal branch supplies the lining of larynx as far as the vocal cords
-External laryngeal branch supplies the cricothyroid muscle and the cricopharyngeus portion of the inferior constrictor
Recurrent laryngeal nerve supplies the remaining intrinsic muscles of the larynx (except the cricothyroid muscle)
Describe the course of the left and right recurrent laryngeal nerve.
The right recurrent laryngeal nerve originates below the beginning of the subclavian artery arching below it to return to the larynx in groove between trachea and esophagus.
The left recurrent laryngeal nerve arches below and behind the aorta to the left of the ligamentum arteriosum and ascends in the groove between trachea and esophagus.
What is supplied by the recurrent laryngeal nerves? What is the exception? ***
The recurrent laryngeal nerves supply sensory and motor
-supply motor fibers to all muscles of the larynx except the cricothyroid muscle
-supply sensory fibers to trachea and larynx below the level of the vocal cords.
What type of fibers are carried by vagal branches beow the recurrent laryngeal nerves, and what do they innervate?
Carry preganglionic parasympathetic fibers and visceral sensory fibers for thoracic/abdominal viscera
What are the symptoms of lesions of the vagus nerve (6)?
Increased pulse rate
Decreased rate of respiration
Sensation of suffocation
Hoarse, low voice
What is used to test the functions of the vagus?
Efferent limb of the gag reflex, faulty movement of the uvula, and laryngoscope to identify paralyzed vocal cord on the affected side.
What 2 muscles are innervated by the accessory nerve (XI)
Innervates the sternocleidomastoid muscle and the trapezius muscle
What would result from lesions to the accessory nerve?
Lesions result in weakness in turning the head to the opposite side as well as a sagging of the shoulder
Where does the accessory nerve (XI) emerge from?
Emerges from the sides of upper five cervical segments of spinal cord between dorsal and ventral rootlets of those respective spinal nerves
Where does the hypoglossal (XII) emerge from?
Emerges from medulla from the pre-olivary sulcus (9, 10, 11 come from the post-olivary sulcus) in line with ventral roots of spinal nerves
What type of fibers are carried by the hypoglossal?
Purely motor nerves
Where does the hypoglossal leave the skull? Where do CN 9, 10, and 11 leave the skull?
XII - through the hypoglossal canal
IX, X, and XI - through the jugular foramen
What is supplied by the hypoglossal nerve? What is an exception to the rule, and what supplies that exception?
Supplies all intrinsic and extrinsic muscles of the tongue, except the palatoglossus, which is supplied by the vagus