2e. Pathways of CNs Flashcards Preview

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Flashcards in 2e. Pathways of CNs Deck (12)
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1
Q

Pathway: Olfactory N.

A
  • Origin: receptors (bipolar neurons) in olfactory mucosa of nasal cavity
  • Travels through foramina in cribriform plate of ethmoid bone
  • Synapses in olfactory bulbs (anterior cranial fossa)
2
Q

Pathway: Optic N.

A
  • Origin: retina of the eye
  • Enters cranium via optic foramen of sphenoid bone
  • Unite at optic chiasm
  • Optic tracts travel to lateral geniculate nucleus of thalamus
  • Information forwarded to occipital lobe
3
Q

Pathway: Oculomotor N.

A
  • Origin: oculumotor and Edinger Westphal nuclei within mesencephalon
  • Leaves cranium via superior orbital fissure
  • Travels to eye and eyelid
    • Parasympathetic fibers to ciliary ganglion
    • Postganglionic parasympathetic fibers to iris and ciliary muscle
4
Q

Pathway: Trochlear N.

A
  • Origin: trochlear nucleus within mesencephalon
  • Leaves cranium via superior orbital fissure
  • Travels to superior oblique muscle
5
Q

Pathway: Abducens N.

A
  • Origin: pontine nucleus in pons
  • Leaves cranum through superior orbital fissure
  • Travels to lateral rectus muscle
6
Q

Pathway: Trigeminal N.

A
  • Origin: pons
  • V1: Enters cranium via superior orbital fissure
    • Travel to trigeminal ganglion before entering pons
  • V2: Enters cranium via foramen rotundum
    • Travel to trigeminal ganglion before entering pons
  • V3: Motor fibers leave pons and exit cranium via oramen ovale
    • Sensory fibers travel through foramen ovale to trigeminal ganglion then pons
7
Q

Pathway: Facial N.

A
  • Origin: nuclei within the pons
  • Sensory fibers from tongue via chorda tympani branch of facial n.
    • Through tiny foramen to enter skull
    • Synapse at geniculate ganglion of facial n.
  • Somatic motor fibers leave pons and enter temporal bone through internal auditory canal
    • Project through temporal bone
    • Emerge from stylomastoid foramen
  • Parasympathetic motor fibers leave pons and enter internal auditory canal
    • ​Leave w/ greater petrosal n. or chroda tympani n. and travel to autonomic ganglion before innervating glands
8
Q

Pathway: Glossopharyngeal N.

A
  • Origin: sensory (taste buds and mucosa of post 1/3 of tongue & carotid bodies) and motor (nuclei in medulla oblongata)
  • Sensory fibers from origins along nerve through inferior or superior ganglion into jugular foramen then pons
  • Somatic motor fibers leave cranium via jugular foramen to stylopharyngeus m.
  • Sensory fibers go to post 1/3 tongue and carotid bodies
  • Parasympathetic motor fibers to otic ganglion then parotid gland
9
Q

Pathway: Vagus N.

A
  • Origin: motor nuclei in medulla oblongata
  • Leaves cranium via jugular foramen traveling and branching in neck, thorax, and abdomen
  • Snesory neuron cell bodies located in superior and inferior ganglia assoc with nerve
10
Q

Pathway: Accessory N.

A
  • Motor nuclei in SC
  • Spinal roots travel superiorly to enter skull through foramen magnum
  • Cranial and spinal roots merge and leave skull via jugular foramen
  • Outside skull cranial root splits to travel with CN X
  • Spinal roots travel to SCM and trapezius
11
Q

Pathway: Hypoglossal N.

A
  • Origin: hypoglossal nucleus in medulla oblongata
  • Leaves cranium via hypoglossal canal then travels inferior to mandible and to inferior surface of tongue
12
Q

Pathway: Vestibulocochlear N.

A
  • Origin: hair cells in vestibule of inner ear and cochlea of inner ear
  • Sensory cell bodies of vest branch in vestibular ganglion
  • Sensory cell bodies of cochlear branch in spiral ganglion near cochlea
  • Branches merge and enter cranial cavity through internal auditory canal
  • Travel to junction of pons and medulla oblongata