Cranial nerves wk5

Question 1

Olfactory Nerve

Answer 1

SSA, foramen: Cribriform plate (ethmoid)
Anosmia = loss of smell

Question 2

Optic Nerve

Answer 2

SSA,
Photoreceptors located in the retina
Foramen: optic canal
Visual info from nasal retina cross-over to opposite side via the optic chiasm
Visual info travels via optic tract to Lateral Geniculate Nucleus
Info integrated in visual cortex of occipital lobe
Lesion - complete/partial loss vision

Question 3

Oculomotor nerve

Both motor and visceral

Answer 3

Foramen: superior orbital fissure

Visceral motor (GVE)
Ciliary ganglion: parasympathetic ganglion
Parasympathetic fibres innervate:
- sphincter pupillae (pupillary constriction)
- ciliary muscles (accomodation)
CNS nucleus: Edinger - Westphal
Lesion: dilated pupil, ptosis, loss pupillary reflex

Question 4

Eyelid muscle is

Answer 4

levator palpebrae superioris

Question 5

Accommodation

changing of the curvature of the eye

Answer 5

Focus on objects - far to near
* Convergence
* Pupillary constriction
* Lens thickening

1. Medial rectus contraction –
   convergence
2. Pupillary convergence
3. Ciliary muscle contraction –
   lens thickness

Question 6

Trochlear nerve

Answer 6

Innervates superior oblique (extraocular
muscle) (GSE)
Foramen: superior orbital fissure
CNS Nucleus: Trochlea
Lesion: inability to look down when eye adducted

Question 7

Abducens muscle

Answer 7

Innervates lateral rectus (extraocular
muscle) (GSE)
Foramen: superior orbital fissure
CNS Nucleus: Abducens
Lesion - no lateral eye movement

Question 8

Trigeminal Nerve
- largest cranial nerve

Answer 8

General sensory nerve for the head (GSA)
Three main branches
* Ophthalmic (V1): sensory
* Maxillary (V2): sensory
* Mandibular (V3): sensory and motor

Foramen:
* superior orbital fissure: V1
* foramen rotundum: V2
* foramen ovale: V3

CNS Nucleus: Trigeminal

Question 9

Trigeminal ganglion - sits in depression in

Answer 9

petrous temp. bone

Question 10

Trigeminal: Mandibular V3
Motor info to (GSE):
* muscles of mastication - temporalis,
masseter, medial and lateral pterygoid
* tensor tympani
* tensor veli palatini
* ant. belly digastric
* mylohyoid

Lesion:
1. loss sensory and pain info from each of
3 divisions,
2. loss motor function - muscles
mastication