Cranial nerves 1 Flashcards
what are the 7 modalities of the cranial nerves nuclei
somatic afferent
special visceral afferent
general visceral afferent
special somatic afferent
somatic efferent
special visceral efferent
general visceral efferent (parasympathetic)
what are the 7 modalities of the cranial nerves nuclei
somatic afferent
special visceral afferent
general visceral afferent
special somatic afferent
somatic efferent
special visceral efferent
general visceral efferent (parasympathetic)
where do cranial nerves pass through
foramina on cranial bones
discuss the route of the olfactory nerve
originates in the olfactory region- where olfactory receptors are found. (which is the upper third of the nasal cavity- septum and roof of nasal cavity– olfactory region)
the receptors are extensions of bipolar neurons
the receptors are stimulated by humidity odour molecules are dissolved- if air dry you will lose smell sensation.
neurons pick up sensation and central extensions form olfactory nerve.
olfactory nerves passes through the cribriform plate of ethmoid bone (very thin and perforated) into anterior cranial fossa and synapse within secondary neurons in the olfactory bulb.
the axons of the neurons in the olfactory bulb form the olfactory tract
olfactory tract goes backwards- separates into two bundles,
medial bundle projects to other olfactory bulb (how we determine where smell is coming from- medial bundle inhibits neuron from other side- so only one side will be activated).
lateral bundle goes to olfactory cortex DOES NOT GO TO THALAMUS.
from cortex to limbic system, hypothalamus, reticular formation.
what anchors the olfactory bulb
dura mater
why are the olfactory neurons special
basal cells have capacity to regenerate to bipolar (olfactory) neurons- ONLY NEURONS THAT CAN RETAIN REGENERATION PROPERTIES THROUGHOUT LIFE
bipolar neurons die every 40-60 days
therefore can be used as stem cells
What is anosmia and some causes
inability to smell
infection of upper respiratory tract
trauma causes the anterior cranial fossa and nasal cavity to communicate
fossa has CSF so = rhinorrhoea (blood stained CSF)
also cribriform indirectly fractures
discuss the innervation of the trigeminal nerve
V1- sensory
V2- sensory
V3- mixed
what are the 4 nuclei and 2 roots of the trigeminal nerve, plus their location
- sensory roots to:
mesencephalic nucleus (ascend towards midbrain)
principal (pontine) nucleus (in pons)
spinal nucleus (in pons, medulla and spinal cord) - motor roots from:
motor nucleus (in pons)
what does the trigeminal nerve supply
general, conscious sensation to most of face, orbital, nasal and oral cavities.
skin from vertex to chin (except angle of the mandible)
describe the routes of the trigeminal nerves
V1-> lateral wall of cavernous sinus -> SUPERIOR ORBITAL FISSURE-> orbit
V2-> lateral wall of cavernous sinus ->FORAMEN ROTUNDUM ->pterygopalatine fossa
V3->FORAMEN OVALE-> infratemporal fossa
sensory fibres all synapse in the trigeminal ganglion (as is sensory- like dorsal root ganglion), motor fibres run below
does the ophthalmic nerve carry sympathetics
Carry sympathetic fibres from T1, T2
sympathetics come around internal carotid artery, into cranial cavity and join ophthalmic nerve.
gives off meningeal branch near trigeminal ganglion that supplies dura
what branches the ophthalmic nerve give off
- lacrimal
- frontal
- nasociliary
what does the lacrimal nerve (V1) supply
general sensation- lacrimal gland, conjunctiva, upper eyelid
parasympathetic fibers of facial nerve to lacrimal gland
what does the frontal nerve (V1) supply and what does it divide into
divides into supra-orbital and supra-trochlear nerve
supplies upper eyelid, conjuctiva, frontal sinus and scalp (as far back as vertex)
what does the nasociliary nerve supply
supplies ethmoidal sinuses
sensation to the cornea of the eye
gives off long ciliary nerves- carry sympathetics to eye, anterior and posterior ethmoidal nerves, before continuing as infratrochlear nerve
CORNEAL REFLEX
what is the afferent limb of the cornea reflex
how do test function
nasociliary nerve
touch tip of nose (area only supplied by nasociliary nerve
efferent limb is facial nerve (make you close eye)
what branches does the maxillary nerve send (V2)
zygomatic and infra-orbital branches into the orbit via inferior orbital fissure
-infra-orbital nerve exits the orbit via infra-orbital canal->infra orbital foramen
sends palatine and superior alveolar branches to the palate and upper teeth
what does the maxillary nerve (V2) supply
lateral forehead
zygomatic region
lower lid
side of nose
cheek
upper lip
what branches does the mandibular nerve give off (V3)
gives off auriculotemporal, masticatory, lingual and inferior alveolar branches
what does the mandibular (V3) suply
skin of auricle and temple
cheek, posteriorly
lower lip and chin
general sensation to anterior 2/3 of the tongue
floor of the mouth
lower gums and teeth
what is the skin over the angle of the mandible supplied by
cervical plexus
NOT trigeminal
what
