Cranial Nerves Flashcards
name the cranial nerves in the order of 1-12
olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulochochlear, glossopharyngeal, vagus, accessory, hypoglossal
what are the 3 main functional components of the cranial nerves?
motor to voluntary muscles, motor to involuntary muscles, sensory
where are the branchial motor nerve transmissions from?
pharyngeal arches
where are the somatic motor nerve transmissions from?
NOT the pharyngeal arches
name 2 involuntary muscles that the cranial nerves innervate
sphincter pupillae and lacrimal glands
where are the sensory transmissions of the cranial nerves from?
from viscera e.g. lungs and bronchi, general sensation, special senses
what is the function of the olfactory nerve?
smell
what is olfactory epithelium?
ciliated pseudostratified columnar
where does smell come from?
nasal mucosa of each nasal cavity, nasal septum and superior conchae
what are superior conchae?
folds inside the nose
what is anosmia?
the loss of the sense of smell e.g. with a cold
what is regenerating epithelium?
epithelium that can regenerate
what is the only nerve with regenerating epithelium?
olfactory nerve
in a clinical environment how is the olfactory nerve tested?
see if the patient can smell toothpaste
what is the function of the optic nerve?
vision
where are the nerve cell bodies of the optic nerve?
the retina
where does the optic nerve come from?
orbital canal (optic chasm) and the left nerve joins the right
what part of the eye does vision come from?
retina
what fatty tissue surrounds and supports the optic nerve?
myelin
what happens to the optic nerve during multiple sclerosis?
it demyelinates causing altered vision
how is the optic nerve tested?
get the patient to read
what does the oculomotor nerve supply?
the muscle outside the eyeball to move it up and down and side to side
what does the superior rectus do?
moves eye up
what does the medial rectus do?
moves eye inwards towards the nose
what does the inferior oblique do?
turns eye upwards and outwards
what does the levator palpebrae superioris do?
holds the upper eyelid up a bit more
what is the nerve supply to the sphincter papillae and the ciliary muscle?
parasympathetic
what does the sphincter papillae do?
causes pupil to constrict to protect eye during bright lights
what does the ciliary muscle do?
it is responsible for accommodation and it focuses on what you’re looking at
where does the visceral motor nerve supply of the oculomotor nerve go via?
the ciliary ganglion
if there is increased pressure inside the skull what happens to the oculomotor nerve?
it stretches the nerve and any damage to this nerve means a dilated pupil
what does the trochlear nerve supply?
one eye muscle (superior oblique)
where are the trochlear nerve cell bodies located?
in the midbrain
what does the superior oblique do?
turns the eye downwards and outwards
what happens if the trochlear nerve is paralysed?
the patients cant look down
what is dipoplia?
double/blurred vision when looking down
what are the three branches of the trigeminal nerve?
ophthalmic (V1), maxillary (V2), mandibular (V3)
what is the function of the ophthalmic division of the trigeminal nerve?
general sensory from corner, skin of forehead, scalp, eyelids, nose, mucosa of nasal cavities and paranasal sinuses
what area does the ophthalmic division of the trigeminal nerve cover?
over forehead to tip of nose
what is the function of the maxillary division of the trigeminal nerve?
general sensory from face over maxilla, upper lip, maxillary teeth and maxillary sinuses
what nerve supplies the maxillary teeth?
the superior alveolar nerve from the maxillary division of the trigeminal nerve
what area does the maxillary division of the trigeminal nerve cover?
over front of face
how is the maxillary division of the trigeminal nerve tested?
by touching parts randomly with the patients eyes closed
what is the function of the mandibular division of the trigeminal nerve?
general sensory (NOT TASTE) of the mandible, mandibular teeth, mucosa of mouth and the anterior 2/3 of the tongue
what nerve supplies the mandibular teeth?
the inferior alveolar nerve of the mandibular division of the trigeminal nerve
where does the mandibular division of the trigeminal nerve come from?
it comes out at the front of the chin as the mental nerve
how do you test the mandibular division of the trigeminal nerve?
test the symmetry of the left and right temporalis
what is the nerve supply of the abducens nerve?
somatic motor
where does the abducens nerve come from?
the pons
what does the abducens nerve supply?
lateral rectus
what does the lateral rectus do?
moves eye outwards and away from the nose
what does LR6 SO4 mean?
lateral rectus supplied by 6, superior oblique supplied by 4, everything else supplied by 3
what nerves supply the muscles of the eye?
oculomotor, trochlear and abducens
how is the abducens nerve tested?
by following a finger in an H shaped pattern
what are the 3 functions of the facial nerve?
branchial motor, special sensory, visceral motor
clinically, what is the most important function of the facial nerve?
branchial motor
what does the branchial motor supply of the facial nerve supply?
muscles of facial expression, scalp and stapedius
what is hyperacusis?
when sounds are louder on one side than the other
what is the special sensory supply of the facial nerve to?
taste to anterior 2/3 of the tongue and palate
what is the visceral motor supply of the facial nerve?
parasympathetic to submandibular and sublingual, also supplies salivary glands, lacrimal gland and glands of nose and palate
what facial structure does the facial nerve pass through?
the parotid gland but it does not supply it
what is the function of the vestibulocochlear nerve?
hearing
what is an internal acoustic neuroma?
benign conditions, tumour growing on CN VIII, risks such as hearing and balance affected on that side if the nerve is taken out, tumours grow 1-5mm per year so presentation of the tumour can be late on
how do we test the vestibulocochlear nerve?
it requires advanced testing
what are all the functions of the glossopharyngeal nerve?
somatic motor, visceral motor, visceral sensory, somatic sensory, special sensory
what is the somatic motor supply of the glossopharyngeal nerve?
motor to stylopharyngeus - helps to raise the pharynx
what is the visceral motor supply of the glossopharyngeal nerve?
parasympathetic to parotid gland to secrete sliva
what nerve supplies the parotid gland?
glossopharyngeal
what is the visceral sensory supply of the glossopharyngeal nerve?
parotid gland, pharynx and middle ear
what is the special sensory supply of the glossopharyngeal nerve?
taste to posterior third of the tongue
what is the somatic sensory supply of the glossopharyngeal nerve?
external ear
what is the overall function of the vagus nerve?
rest and digest - raise gut motility and heart rate
what nerve controls swallowing?
vagus
what are the functions of the vagus nerve?
somatic motor, visceral motor, visceral sensory, special sensory and general sensory
what is the somatic motor supply of the vagus nerve to?
muscles of the pharynx, larynx, palate and upper third of the oesophagus
what is the visceral motor supply of the vagus nerve to?
parasympathetic to trachea, bronchi, GI tract and heart
what is the visceral sensory supply of the vagus nerve to?
tongue, larynx, respiratory tract, heart, upper GI tract to left colic flexure
what is the special sensory supply of the vagus nerve to?
epiglottis and palate (taste fibres)
what is the general sensory supply of the vagus nerve to?
auricle, external auditory meatus
how can the glossopharyngeal and vagus nerve be tested?
by saying ahhhh
what is the nerve supply of the accessory nerve?
somatic motor
what does the accessory nerve supply?
sternocleidomastoid and trapezius
how is the accessory nerve tested?
by raising shoulders and stopping the examiner pushing downwards
what is the nerve supply of the hypoglossal nerve?
somatic motor
what does the hypoglossal nerve supply?
the intrinsic and extrinsic muscles of the tongue (except palatoglossus)
how is the hypoglossal nerve tested?
by sticking the tongue out
