Cranial nerves 1

Question 1

what are the 7 modalities of the cranial nerves nuclei

Answer 1

somatic afferent
special visceral afferent
general visceral afferent
special somatic afferent

somatic efferent
special visceral efferent
general visceral efferent (parasympathetic)

Question 1

what are the 7 modalities of the cranial nerves nuclei

Answer 1

somatic afferent
special visceral afferent
general visceral afferent
special somatic afferent

somatic efferent
special visceral efferent
general visceral efferent (parasympathetic)

Question 2

where do cranial nerves pass through

Answer 2

foramina on cranial bones

Question 3

discuss the route of the olfactory nerve

Answer 3

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.

Question 4

what anchors the olfactory bulb

Answer 4

dura mater

Question 5

why are the olfactory neurons special

Answer 5

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

Question 6

What is anosmia and some causes

Answer 6

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

Question 7

discuss the innervation of the trigeminal nerve

Answer 7

V1- sensory
V2- sensory
V3- mixed

Question 8

what are the 4 nuclei and 2 roots of the trigeminal nerve, plus their location

Answer 8

1. sensory roots to:
   mesencephalic nucleus (ascend towards midbrain)
   principal (pontine) nucleus (in pons)
   spinal nucleus (in pons, medulla and spinal cord)
2. motor roots from:
   motor nucleus (in pons)

Question 9

what does the trigeminal nerve supply

Answer 9

general, conscious sensation to most of face, orbital, nasal and oral cavities.
skin from vertex to chin (except angle of the mandible)

Question 10

describe the routes of the trigeminal nerves

Answer 10

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

Question 11

does the ophthalmic nerve carry sympathetics

Answer 11

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

Question 12

what branches the ophthalmic nerve give off

Answer 12

1. lacrimal
2. frontal
3. nasociliary

Question 13

what does the lacrimal nerve (V1) supply

Answer 13

general sensation- lacrimal gland, conjunctiva, upper eyelid
parasympathetic fibers of facial nerve to lacrimal gland

Question 14

what does the frontal nerve (V1) supply and what does it divide into

Answer 14

divides into supra-orbital and supra-trochlear nerve
supplies upper eyelid, conjuctiva, frontal sinus and scalp (as far back as vertex)

Question 15

what does the nasociliary nerve supply

Answer 15

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

Question 16

what is the afferent limb of the cornea reflex
how do test function

Answer 16

nasociliary nerve
touch tip of nose (area only supplied by nasociliary nerve
efferent limb is facial nerve (make you close eye)

Question 17

what branches does the maxillary nerve send (V2)

Answer 17

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

Question 18

what does the maxillary nerve (V2) supply

Answer 18

lateral forehead
zygomatic region
lower lid
side of nose
cheek
upper lip

Question 19

what branches does the mandibular nerve give off (V3)

Answer 19

gives off auriculotemporal, masticatory, lingual and inferior alveolar branches

Question 20

what does the mandibular (V3) suply

Answer 20

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

Question 21

what is the skin over the angle of the mandible supplied by

Answer 21

cervical plexus
NOT trigeminal

Question 22

what