Cranial Nerves Flashcards
how many cranial nerves are there ?
12 pairs
as nerves are soft and they pass through holes in hard bone. what three things are nerves prone to ?
- inflammation
- fracture
- tumours
what are the three type of sensory cranial nerves are there?
general
visceral
special
what are the two types of motor fibres in cranial nerves are there?
somatic
visceral
do cranial nerves have parasympathetic and sympathetic fibres ?
no
- just parasympathetic
what function do the special sensory fibres have?
taste, smell, vision, hearing and balance
from what areas do visceral sensory fibres receive input?
pharynx larynx heart lungs gut (all area not conscious of)
from what areas do general sensory fibres receive input?
touch, temp and pain from skin and mucus membranes
out of the there types of neurons, what type of neuron is used in sensory and motor fibres?
sensory = pseudo unipolar motor = multipolar
where is the cell body for sensory fibres ?
dorsal root ganglia
what is the phrase used to remember the names of the 12 cranial nerves ?
Oh Oh Oh To Touch And Feel Very Good Velvet Ah Heaven
what are the names of the 12 cranial nerves ?
Oh - olfactory Oh - optic Oh - oculomotor To - trochlear Touch - trigeminal And - abducens Feel - facial Very - vestibulocochlear Good - glossopharyngeal Velvet - vagus Ah - accessory Heaven - hypoglossal
what is the phrase used to determine if the nerves are motor or sensory or both ?
Some Say Marry Money But My Brother Says Big Brains Matter More
what bone do the olfactory nerve branches pass through?
the cribriform plate of the ethmoid bone
what do the olfactory nerve branches form before passing through the cribriform plate in the anterior cranial fossa?
olfactory bulb
what sense is due to the olfactory nerve ?
smell
what is anosmia ?
loss of smell
what sense is due to the optic nerve ?
vision
what condition is caused by an increased pressure of CSF in the eyes?
papilloedema
when the right optic nerve is cut what is the result ?
right eye blindness
what is the result when
- the medial section of the optic chiasma is cut?
the to medial side of the retina can’t get their information to the brain to be interpreted into an image so the two lateral field of vision are lost
= bilateral hemianopsia
what is anopsia ?
a defect in the visual field.
what is the result when
- the right optic tract is cut?
the two right sides of the retina information are lost so the two left sides of the field of vision are lost
= left homonymous hemianopsia
through which foramen does the oculomotor nerve pass through?
superior orbital fissure
what are the two components of the oculomotor nerve ?
somatic
autonomic
what does parasympathetic response have on the eye ?
pupil constriction
accommodation of ciliary body
what are the clinical signs when the oculomotor nerve is damaged?
dropping upper eye lid
eyeball abducted and depressed
no pupillary reflex
no accommodation of the len
how many of the extrinsic ocular muscles are controlled by the oculomotor nerve ?
4
through which foramen does the trochlear nerve pass through?
superior orbital fissure
what extrinsic ocular muscle is controlled by the trochlear nerve ?
superior oblique
what is the clinical sign when the trochlear nerve is damaged ?
diplopia = double vision
what is diplopia ?
double vision
where abouts from the brain doe the trochlear nerve come out from?
the mid brain
where abouts does the abducent nerve leave the brain from?
between the pons and medulla
through which foramen does the abducent nerve pass through?
superior orbital fissure
what is the function of the abducent nerve ?
abduct the eye by innervating the lateral rectus
what is the clinical sign for damage to the abducent nerve ?
medial deviation of the eye which causes diplopia
what foramen does the trigeminal V1 nerve pass through?
superior orbital fissure
how many branches of the trigeminal nerve are there?
3
what are the three branches of the trigeminal nerve?
V1 - ophthalmic
V2 - maxillary
V3 - mandibular
what foramen does the trigeminal V2 nerve pass through?
foramen rotunda
what foramen does the trigeminal V3 nerve pass through?
foramen ovale
which branch of the trigmeinal nerve contains motor fibres ?
V3
what is trigeminal neuralgia ?
nerves work wrong, lightly brushing the skin causes a lot of pain, nerves can’t process sensory information properly
what are some complications when the trigeminal nerve is damaged ?
loss of sensation in the face
loss of corneal or sneezing reflex
paraylsis of muscles of mastication
what foramen does the facial nerve pass through to leave the cranium?
internal acoustic foramen
what foramen does the facial nerve pass through to enter outside the bones of the face?
stylomastoid foramen
where abouts from the brain does the facial nerve come out from?
between the pons and the medulla
what four fibres are found in the facial nerve ?
somatic motor
autonomic motor
special sensory
general sensory
what is the special sensory fibres of the facial nerve used for?
taste from anterior 2/3rd of tongue & soft palate
what parasympathetic innervation is due to the facial nerve ?
parasympathetic innervation of submandibular & sublingual salivary glands, lacrimal glands, glands of nose & palate
as well as the muscles of facial expression what other muscle is supplied by the facial nerve ?
stapedius of the middle ear
what is the function of the stapedius of the middle ear?
dampens the sound
where abouts from the brain does the vestibulocochlear nerve emerge from?
between the pons and medulla
what two nerves does the vestibulocochlear nerve form?
vestibular nerve
cochlear nerve
what are the three structures that give a sense of position and balance ?
semi-circular canals
utricle
saccule
what are some clinical signs that the vestibulocochlear nerve is damaged ?
tinnitus
deafness
vertigo
nystagmus
what is nystagmus ?
involuntary rapid eye movements
where does the glossopharyngeal nerve emerge from in the brain?
medulla
through which foramen does the glossopharyngeal nerve pass through?
jugular foramen
what fibres does the glossopharyngeal nerve contain?
special sensory general sensory visceral sensory visceral motor somatic motor
what does the carotid body detect?
changes in the composition of the blood by the chemoreceptors in the common carotid artery
what does the carotid sinus detect ?
detects change in blood pressure in the carotid artery
what is the function of the special sensory component of the glossopharyngeal nerve?
taste from the posterior 1/3rd of the tongue
what salivary gland is innervated by the glossopharyngeal nerve ?
parotid gland
what three nerves pass through the jugular foramen ?
glossopharyngeal
vagus
accessory
what are two clinical signs that the glossopharyngeal nerve has been damaged ?
loss of gag reflex
loss of taste from the posterior 3rd of the tongue
from which part of the brain does the vagus nerve emerge from?
the medulla
what foramen does the vagus nerve pass through?
jugular foramen
what fibres are contained in the vagus nerve ?
special sensory general sensory visceral sensory visceral motor somatic motor
what is the general sensation of the vagus nerve?
sensation of the auricle and external acoustic meatus
what muscles does the accessory nerve supply?
striated muscle of the soft palate, pharynx, larynx
and SCM and trapezius
state a clinical sign that the accessory nerve may be damaged ?
weakness in turning head and shrugging shoulder
what are the relative size of the cranial nerve and spinal root length of the accessory nerve ?
short cranial nerve
long spinal roots
which foramen does the hypoglossal nerve pass through ?
hypoglossal canal
where does the hypoglossal nerve emerge from in the brain?
medulla
what is the function of the hypoglossal nerve ?
motor control of the muscles of the tongue
which side would the tongue deviate towards if the hypoglossal nerve was cut on one side?
would deviate towards the damaged side
during which operation is the hypoglossal nerve vulnerable to getting damaged ?
tonsillectomy
