Cranial Nerves Overview Flashcards
Structural classification of nervous system
- CNS: Brain and spinal cord
- PNS: Spinal nerves and ganglia
Functional classification of the nervous system
- Somatic nervous system, voluntary
- Autonomic nervous system, involuntary
Motor component of somatic nervous system
Skeletal muscle contraction
Sensory component of somatic nervous system
Touch, pain, temperature, etc.
Motor component of autonomic nevous system
- Sympathetic
- Parasympathetic
- Cardiac and smooth muscle, glands
Sensor component of autonomic nervous system
Sensation from the viscera
Sympathetic nervous system
- Functions to mobilize resources of body when demands are increased
- Thoracolumbar
Parasympathetic
Functions in the restoration or conservation of energy and resources, craniosacral system
Parasympathetic nervous system vs sympathetic nervous system
- Distinct CNS origins
- Distinct ganglia
- Same targets, opposing actions
Visceral motor innervation structure
2-neuron pathway with an intervening ganglion
How many cranial nerves are there?
12
Somatic functions of cranial nerves
Provides motor and sensory innervation to somatic structures in the head and neck
Autonomic functions of the cranial nerves
Mediate sensation from the viscera and provide parasympathetic (visceral motor) innervation for visceral functions
Special sensory function of cranial nerves
Mediate vision, hearing, balance, olfaction, and taste
Cranial nerves emerging from the midbrain
III, IV
Cranial nerves emerging from the pons
V, VI, VII, VIII
Cranial nerves emerging from the medulla
IX, X, XI, XII
What cranial nerves do not come from the brainstem?
I and II
CN I is associated with the…
Cerebral hemispheres
CN II is associated with the…
Thalamus
What CN does not emerge from the ventral part of the brainstem/
CN IV Trochlear nerve
Sensory cranial nerves
I, II, VIII
Motor cranial nerves
III, IV, VI, XI, XII
Mixed cranial nerves
V, VII, IX, X
General/somatic sensory CNs are… What are their functions?
- V, VII, IX, X
- Sensation from the skin, joints, muscle spindles, etc.
- Touch, pain, pressure, vibrations, etc.
Visceral sensory CNs are… What are their functions?
- IX, X
- Sensation from cervical, thoracic, and abdominal viscera
Special sensory CNs are… What are their functions?
- I, II, VIII, VII, IX, X
- Sensation from the specialized receptors that mediate olfaction, vision, hearing, balance, and taste
General somatic motor CNs are… What are their functions?
- III, IV, V, VI, VII, IX, X, XI, XII
-Motor innervation skeletal muscles
Visceral motor CNs are… What are their functions?
- Parasympathetic innervation to visceral structures
- Cardiac muscle, smooth muscle glands
Jugular foramen
IX, X, XI
Internal auditory meatus
VII, VIII
Superior orbital fissure
III, IV, V, VI
Cavernous sinus
III, IV, V1, V2, VI
Olfactory receptor neurons are located where? What do they respond to?
- Within the olfactory mucosa of the roof of the nasal cavity
- Respond to airborne odorant molecules
Where are the olfactory dendrites located?
Olfactory epithelium
Where do the olfactory nerves pass through?
Cribriform plate of the ethmoid bone
Damage/injury to the olfactory nerve can result in…
Result in olfactory deficits/lost of smell
Anosmia
Loss of smell
How is light bent/refracted in the eye
By the curvatures of the cornea and the lens
What foramen does the optic nerve go through?
Optic foramen in the sphenoid bone
Optic chiasm
- Some fibers cross over, some stay on the same side
- Then continues to optic tract
Damage of the optic nerve can result in…
Visual deficits or blindness
Oculomotor nerve, CN III controls…
- Medial rectus muscle
- Superior rectus muscle
- Inferior rectus muscle
- Inferior oblique muscle
What nerve controls the levator palpebrae superioris muscle?
CN III
Levator palpebrae superioris muscle
Visceral motor component, parasympathetic
How does the Levator palpebrae superioris muscle work?
- Taking parasympathetic information to ganglion in eye called ciliary ganglion
- Signal goes to ciliary body
- And then signal goes to the sphincter pupillae muscle
Ciliary body
Lens accommodation
Sphincter pupillae muscle
Pupil constriction
CN IV
Superior oblique muscle
Superior oblique muscle action
Depress and abduct the eye
CN VI
Lateral rectus muscle
Lateral rectus muscle action
Abduct the eye
Damage to CN III, IV, or VI result in…
Blurred vision
Diplopia
Blurred vision
CN V cell bodies are located…
In the trigeminal ganglion
CN V1
Ophthalmic branch
CN V1 exits through the
Superior orbital fissure
CN V1 gives rise to…
Sensory branches
CN V2
Maxillary branch
CN V2 exits through the
Foramen rotundum
CN V2 gives rise to…
Sensory branches
CN V3
Mandibular branch
CN V3 gives rise to…
Sensory and motor branches
CN V3 exits through the foramen ovale
CN V function is…
Mediate sensation from the skin of face, teeth, oral, nasal, and some pharyngeal mucosa
Motor branches of V3
provide motor innervation to the muscles of mastication (chewing muscles) and other muscles
CN V2 and V3 mediation sensation from…
Teeth & adjacent gingiva
Damage/injury of the overall trigeminal nerve results in…
Impaired sensation
Damage/injury to motor branches of CNV3 can result in…
- Masticatory muscle paralysis/weakness
- Jaw laxity
- Contralateral deviation of jaw at rest
Trigeminal neuralgia
Facial neuropathic pain syndrome of unknown etiology by sudden shock or stabbing from the maxilla or mandible
CN VII motor function
To muscles of facial expression and more
CN VII sensory function
From skin of external ear
CN VII parasympathetic function
- Lacrimal gland
- Submandibular gland
- Sublingual gland
- Nasal glands
- Oral glands
- Pharyngeal glands
CN VII special sensory functions
Taste on anterior ⅔ of the tongue
CN VII passes through the…
Internal auditory (acoustic) meatus in temporal bone
Damage/lesion to CN VII result in…
Result in paralysis of muscles of facial expression on the side of the face
Bell’s Palsy
Idiopathic facial paralysis
CN IX motor function
Stylopharyngeus muscle in the pharynx
CN IX parasympathetic function
Parotid gland
CN IX general sensory function
Posterior ⅓ of tongue and skin of ear
CN IX special sensory function
For taste on posterior ⅓ of the tongue
CN IX visceral sensory function
From carotid body and carotid sinus
CN IX is located…
Transverse along the jugular foramen with internal jugular vein
CN X motor function
Goes to most muscles of the plate, pharynx, and larynx
CN X parasympathetic function
Goes to thoracic and abdominal viscera
CN X sensory function
From skin of ear, pharynx, and larynx
CN X special sensory functions
For taste on epiglottis
CN X visceral sensory function
From cervical, thoracic, and abdominal viscera
CN X is located…
Transverse along the jugular foramen with internal jugular vein
CN XI has components from the…
Medulla and spine (C1-C5)
Spinal component of CN XI enters the cranial cavity through the…
Foramen magnum
The spinal component and cranial component of CN XI exit the skull through…
The jugular foramen
CN XI motor innervation
- Sternocleidomastoid - trapezius muscles
CN XII exits through the…
Hypoglossal foramen
CN XII goes to the
Anterior cervical triangle into the oral cavity
CN XII motor innervation
Tongue musculature (all the muscles of the tongue
