cranial nerves

Question 1

cranial nerves can contain

Answer 1

sensory or motor fibers

Question 2

motor fibers (efferent)

Answer 2

1. somatic motor: to striated muscles in the orbit, tongue and external neck as well as straited muscles of the face, palate, pharynx, and larynx
2. branchial motor: muscles of the face, palate, pharynx, and larynx are derived form the pharyngeal arches and their somatic motor innervation
3. visceral motor: to glands and involuntary smooth muscle in visceral and blood vessels

Question 3

sensory fibers (afferent)

Answer 3

-somatic (general sensory): transmit general sensation (touch, pressure, heat, cold)
-visceral (general sensory): convey sensation from viscera (carotid body and sinus, pharynx, and trachea)
-special sensory: convey taste, smell, hearing, vision, and balance

Question 4

1. Olfactory Nerve : CN I
   component
   special sense
   exit

Answer 4

-component: smell from nasal cavity
-special sense: smell from nasal cavity
-exit: cribriform plate of the ethmoid bone

Question 5

2. optic nerve CN II
   component:
   special sense
   exit

Answer 5

component; sensory
special sense: sight from retina
-has optic chiasm: right and left tracts of fibers merge, allows field of vision to cross
exit: optic canals from the sphenoid bone

Question 6

3. Occulomotor nerve CN III
   component: motor
   somatic motor:
   visceral motor
   exit

Answer 6

component: motor
somatic motor: extraocular muscles
visceral motor: (pre-synaptic parasympathetic) constricts the pupil and accommodate the lens
exit: superior orbital fissure of the sphenoid bone

Question 7

4. trochlear nerve CN IV
   component:
   somatic motor
   exit

Answer 7

component: motor
somatic motor: superior oblique muscles
exit: superior orbital fissure of the sphenoid

Question 8

5. trigeminal nerve CN V
   component:

Answer 8

sensory and motor

Question 9

5. trigeminal nerve CN V1: opthalmic division
   component: general sensory:
   exit

Answer 9

component: general sensory, from the skin of the forehead, external nose, phitrum of upper lips
exit: supraorbital fissure

Question 10

5. trigeminal nerve CN V2: maxillary divison
   component: general sensory:
   exit

Answer 10

component: general sensory: from skin of the face overlying the maxilla, nasal cavity, upper teeth, and palate
exit: foramen rotundum

Question 11

5. trigeminal nerve CN V3: mandibular division
   components
   generally sensory
   branchial/somatic motor
   exit

Answer 11

components: sensory and motor
generally sensory: from skin over the mandible, lower lip, an TMJ
branchial/somatic motor: muscles of mastication
exit: foramen ovale

Question 12

6. abducent nerve CN VI
   component
   somatic motor
   exit

Answer 12

component: motor
somatic motor: to lateral rectus muscle
exit: superior orbital fissure of sphenoid

Question 13

7. facial nerve CN VII
   components:
   special sensory
   branchial motor and exit
   visceral motor
   common meet

Answer 13

component: sensory and motor
special sensory: taste, from the 2/3rds of the tongue
branchial motor: muscles of facial expression
-exit: stylomastoid foramen
visceral motor: lacrimal gland, nasal, and palatine mucosal glands, submandibular and sublingual glands
exit route meet: internal acoustic meatus

Question 14

facial expression muscles

Answer 14

-temporal, zygomatic, buccal, mandibular, cerivical
-pass through parotid gland
-insert: facial nerve

Question 15

8. vestibulocochlear nerve CN VIII
   component:
   special sensory
   exit

Answer 15

component: sensory
special sensory: hearing and equilibrium from inner ear
exit: internal acoustic meatus to reach the vestibular system (balance) and cochlea (hearing) of the inner ear
-2 separate nerves

Question 16

9. glossopharyngeal nerve CN IX. HAS ALL
   component:
   branchial motor:
   visceral (parasympathetic) motor:
   general somatic sensory
   special sensory
   visceral sensory
   exit

Answer 16

component: sensory and motor
branchial motor: muscle of the pharynx (stylopharyngeus)
visceral (parasympathetic) motor: to the parotid gland
general somatic sensory: palatine tonsil, soft palate, posterior 1/3rd of the tongue
special sensory: taste, from the posterior 1/3rd of the tongue
visceral sensory: from the carotid body (chemoreceptor: O2 saturation), and carotid sinus (baroreceptor: blood pressure).
exit: jugular foramen

Question 17

10. vagus nerve: CN X; HAS ALL
    components:
    branchial motor
    visceral motor
    general somatic sensory
    special sensory
    visceral sensory
    exit

Answer 17

branchial motor: muscles of the pharynx, larynx, and palate
visceral motor: to thoracic and abdominal organs
general somatic sensory: from the skin posterior to the ear and external auditory canal
special sensory: taste, from the epiglottis to the root of the tongue
visceral sensory: from the inferior pharynx and larynx mucosa, thoracic and abdominal viscera
exit: jugular foramen
-only nerve that exits the neck

Question 18

11. spinal accessory nerve: CN XI
    component:
    somatic motor:
    arise:
    exit

Answer 18

component: motor
somatic motor: trapezius and sternocleidomastoid muscles
arise: series of rootlets from the first cervical segments of the spinal cord which enter the skull via foramen magnum
exit: jugular foramen

Question 19

12. hypoglossal nerve: CN XII
    component
    somatic motor
    exit

Answer 19

component: motor
somatic motor: to muscles within the tongue and those that attach to it (styloglossus, hypoglossus, genioglossus) all except paletoglossal muscles
exit: hypoglossal canal

Question 20

CN III, VII, and IX

Answer 20

synapse in one of 4 head ganglia and innervate the eye, lacrimal gland, nasal mucosa, and salivary glands

Question 21

CN X

Answer 21

synapse in an intramural ganglion in the wall of the target organ

Question 22

sacral outflow (S2-4)

Answer 22

through the inferior hypogastric plexus and synapse in a intramural ganglia in the wall of the target organ

Question 23

cranial nerves 3,7, and 9 synapse on

Answer 23

trigeminal nerve