Cranial Nerves 7-12 Flashcards
What fibers does the facial nerve consist of?
The facial nerve consists of sensory, motor and parasympathetic fibers. More precisely:
SVA (Sensory)
GVA (Sensory)
GSA (Sensory)
SVE (Motor) G
VE (Parasympathetic)
What structures do the sensory fibers of the facial nerve innervate?
The sensory fibers of the facial nerve innervate the:
- Taste fibers for anterior 2/3 of the tongue.
- Palate and nasal mucosa.
- Eternal acoustic meatus and the auricle.
What does the motor fibers of the facial nerve innervate?
The motor fibers of the facial nerve innervate the:
- Muscles of facial expression
- Posterior belly of digastric
- Stylohyoid
- Stapedius
What do the parasympathetic fibers of the facial nerve supply?
The parasympathetic fibers of the facial nerve supplies the:
- Lacrimal gland (Produce tears)
- Submandibular gland (Produce a mixture of serous fluid and mucus that enters the oral cavity via the submandibular duct or Wharton duct).
- Sublingual gland (Produce saliva that lubricates food)
- Nasal gland (produce mucosa that traps bacteria etc.)
- Palatine gland (produce mucus)
Where does the facial nerve originate and what is its pathway?
The facial nerve starts in the cerebellopontine angle of the pons, enters the internal acoustic meatus and exits the skull through the stylomastoid foramen.
What reflex does the facial nerve mediate?
The facial nerve mediates the efferent limb of the corneal reflex.
What might the loss of the corneal reflex lead to?
Loss of the corneal reflex might lead to corneal ulcuration (open sore of the cornea).
What is Bell’s Palsy?
Bells Palsy is an ipsilateral paralysis of facial muscles. Half of the face appears to drop.
Due to damage to of the facial nerve, what can the symptoms be?
- Loss of facial expression
- Loss of taste in anterior 2/3 of the tongue and problems with salvation
- Paralysis of the stapedius muscle = Hyperacusis (oversensitive to sounds)
- Problems with lacrimation (secretion of tears)
- Accompanied by problems with hearing and balance - deafness and dizziness.
What ganglion houses all facial sensory cell bodies?
Geniculate ganglion.
What branch of the facial nerve mediates the lacrimal and nasal glands, as well as taste from the palate?
The greater petrosal nerve had parasympathetic fibers that mediate the nasal and lacrimal glands. It is also associated with taste from the palate. It mediates in the pterygopalatine ganglion.
Which branch of the facial nerve supplies the stapedius?
The stapedius is supplied by the stapedial nerve.
Which structures do the Chorda Tympani (branch of the facial nerve) mediate?
The Chorda tympani:
- Has SVA fiber to the anterior 2/3 of the tongue.
- Has parasympathetic GVE fibers to the submandibular and sublingual gland.
What are the 5 motor branches of the facial nerve that innervates facial expression muscles called?
The five branches of facial expression is:
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
What three branches, branches of the facial nerve before passing through the stylomastoid foramen?
- Greater petrosal nerve.
- Stapedial Nerve
- Chorda tympani.
Describe the pathways and branches of the facial nerve
Why can the facial nerve get damaged due to damage or tumor to the parotid gland even though the facial nerve does not innervate it?
The facial nerve does not innervate the parotid gland but it goes through it. Hence, damage to the parotid gland can damage the facial nerve.
What other nerve does the greater petrosal nerve meet in the pterygoid canal?
The greater petrosal nerve (of the facial nerve) with preganglionic parasympathetic fibers meets the deep petrosal nerve (branch of the maxillary nerve) with postganglionic sympathetic fibers int the pterygoid canal.
Which three glands does the nerve of the pterygoid canal (deep and greater petrosal nerve) mediate?
The Lacrimal gland
The nasal glands
The palatine salivary glands
Which nerve surrounds the internal carotid artery and is a part off the internal carotid plexus?
The deep petrosal nerve.
What fibers does the vestibulocochlear nerve consist of?
The vestibulocochlear nerve consists of sensory SSA fibers.
What is the pathway of the vestibulocochlear nerve?
The vestibulocochlear nerve exits the brainstem via the cerebellopontine angle (same as facial nerve), goes through the internal acoustic meatus and innervates sensory cells of the inner ear.
What two branches are of the vestibulocochlear nerve?
The vestibulocochlear nerve has two branches:
- The cochlear branch that innervates the cochlea (hearing)
- The vestibular branch that innervates the vestibule (balance)
What fibers are the glossopharyngeal nerve made up of?
The glossopharyngeal nerve is made up of:
- SVA (Taste 1/3 posterior part of the tongue and the pharyngeal wall)
- GVA (Sensation 1/3 posterior part of the tongue and pharyngeal wall + tympanic cavity and auditory tube + carotid sinus + palatine tonsil and soft palate)
- GSA (External acoustic meatus)
- SVE (Motor - Innervation of the stylopharyngeus)
- GVE (parasympathetic - parotid gland)
