Neuro - Anat & Phys (Cranial nerves anatomy)

Question 1

What is the name and function of CN I?

Answer 1

Olfactory nerve; Smell (only CN without thalamic relay to cortex)

Question 2

What is the only CN without thalamic relay to cortex?

Answer 2

Olfactory (CN I)

Question 3

What is the name and function of CN II?

Answer 3

Optic nerve; Sight

Question 4

What is the name and 4 functions of CN III?

Answer 4

Oculomotor nerve; (1) Eye movement (SR, IR, MR, IO), (2) Pupillary constriction (sphincter pupillae; Edinger-Westphal nucleus, muscarinic receptors), (3) Accommodation, (4) Eyelid opening (levator palpebrae)

Question 5

What is the name and function of CN IV?

Answer 5

Trochlear nerve; Eye movement (SO)

Question 6

What is the name and 3 functions of CN V?

Answer 6

Trigeminal nerve; (1) Mastication, (2) Facial sensation (ophthalmic, maxillary, mandibular divisions), (3) Somatosensation from anterior 2/3 of tongue

Question 7

What is the name and function of CN VI?

Answer 7

Abducens nerve; Eye movement (LR)

Question 8

What is the name and 6 functions of CN VII?

Answer 8

Facial nerve; (1) Facial movement, (2) Taste from anterior 2/3 of tongue, (3) Lacrimation, (4) Salivation (submandibular and sublingual glands), (5) Eyelid closing (orbicularis oculis), (6) Stapedius muscle in ear (note: nerve courses through parotid gland, but does not innervate it)

Question 9

Through which structure does CN VII course through, although it does not innervate it?

Answer 9

nerve courses through parotid gland, but does not innervate it

Question 10

What is the name and 2 functions of CN VIII?

Answer 10

Vestibulocochlear nerve; (1) Hearing, (2) Balance

Question 11

What is the name and 5 functions of CN IX?

Answer 11

Glossopharyngeal nerve; (1) Taste and somatosensation from posterior 1/3 of tongue, (2) Swallowing, (3) Salivation (parotid gland), (4) Monitoring carotid body and sinus chemo- and baroceptors, and (5) Stylopharyngeus (elevates pharynx, larynx)

Question 12

What is the name and 8 functions of CN X?

Answer 12

Vagus nerve; (1) Taste from epiglottic region, (2) Swallowing, (3) Soft palate elevation, (4) Midline uvula, (5) Talking, (6) Coughing, (7) Thoracoabdominal viscera, (8) Monitoring aortic arch chemo- and baroreceptors

Question 13

What is the name and 2 functions of CN XI?

Answer 13

Accessory nerve; (1) Head turning, (2) Shoulder shrugging (SCM, trapezius)

Question 14

What is the name and function of CN XII?

Answer 14

Hypoglossal; Tongue movement

Question 15

State whether the 12 cranial nerves are Motor, Sensory, or Both.

Answer 15

(1) Sensory (2) Sensory (3) Motor (4) Motor (5) Both (6) Motor (7) Both (8) Sensory (9) Both (10) Both (11) Motor (12) Motor; Think: “Some Say Marry Money But My Brother Says Big Brains Matter Most”

Question 16

In general, where are most of the cranial nerve nuclei located?

Answer 16

Located in tegmentum portion of brain stem (between dorsal and ventral portions)

Question 17

Which 2 CN’s have nuclei in the midbrain?

Answer 17

Midbrain - nuclei of CN III, IV

Question 18

Which 4 CN’s have nuclei in the pons?

Answer 18

Pons - nuclei of CN V, VI, VII, VIII

Question 19

Which 3 CN’s have nuclei in the medulla?

Answer 19

Medulla - nuclei of CN IX, X, XII

Question 20

Which CN has its nucleus in the spinal cord?

Answer 20

Spinal cord - nucleus of CN XI

Question 21

In nervous system development, what structure separates sensory versus motor neurons? What are the names of the plates containing each type of these neurons? How do they correlate to cranial nerve nuclei?

Answer 21

Sulcus limitans; Lateral nuclei = sensory (aLar plate); Medial nuclei = Motor (basal plate)

Question 22

Name 5 cranial nerve reflexes.

Answer 22

(1) Corneal (2) Lacrimation (3) Jaw jerk (4) Pupillary (5) Gag

Question 23

What are the afferent and efferent limbs of the Corneal reflex?

Answer 23

Afferent: V1 ophthalmic (nasociliary branch); Efferent: VII (temporal branch: orbicularis oculi)

Question 24

What are the afferent and efferent limbs of the Lacrimation reflex?

Answer 24

Afferent: V1 (loss of reflex does not preclude emotional tears); Efferent: VII

Question 25

What are the afferent and efferent limbs of the Jaw jerk reflex?

Answer 25

Afferent: V3 (sensory - muscle spindle from masseter); Efferent: V3 (motor - masseter)

Question 26

Does loss of the Lacrimation reflex preclude emotional tears?

Answer 26

Afferent: V1 (loss of reflex does not preclude emotional tears); Efferent: VII

Question 27

What are the afferent and efferent limbs of the Pupillary reflex?

Answer 27

Afferent: II; Efferent: III

Question 28

What are the afferent and efferent limbs of the Gag reflex?

Answer 28

Afferent: IX; Efferent: X

Question 29

What are 3 Vagal nuclei?

Answer 29

(1) Nucleus solitarius (2) Nucleus ambiguus (3) Dorsal motor nucleus

Question 30

What is the general function of the Nucleus Solitarius? Give 3 examples of this function. What CN's are associated with it?

Answer 30

Visceral Sensory information (e.g., taste, baroreceptors, gut distention); VII, IX, X; Think: "Solitarium = Sensory"

Question 31

What is the general function of the Nucleus Ambiguus? Give 2 examples of this function. What CN's are associated with it?

Answer 31

Motor innervation of pharynx, larynx, and upper esophagus (e.g., swallowing, palate elevation); IX, X, XI (cranial portion)

Question 32

What is the function of the Dorsal motor nucleus? What CN is associated with it?

Answer 32

Sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI; X

Question 33

Which CN travels through Cribiform plate?

Answer 33

Cribiform plate (CN I)

Question 34

Which CN's travel through Middle cranial fossa? More specifically, through what other structure do they travel?

Answer 34

Middle cranial fossa (CN II-VI) - through sphenoid bone

Question 35

Through which structure does CNII travel? What 2 vessels also pass through this structure?

Answer 35

Middle cranial fossa (CN II-VI) - through sphenoid bone: Optic canal (CN II, ophthalmic artery, central retinal vein)

Question 36

Through which structure does CNIII travel? What other CN's travel with it through this structure? What 5 other vessels/nerves pass through this structure as well?

Answer 36

Middle cranial fossa (CN II-VI) - through sphenoid bone: Superior orbital fissure (CN III, IV, V1, VI, ophthalmic vein, sympathetic fibers)

Question 37

Through which structure does CN V2 travel?

Answer 37

Middle cranial fossa (CN II-VI) - through sphenoid bone: Foramen Rotundum (CN V2)

Question 38

Through which structure does CN V3 travel?

Answer 38

Middle cranial fossa (CN II-VI) - through sphenoid bone: Foramen Ovale (CN V3)

Question 39

Through what structures do the divisions of CN V exit?

Answer 39

V1 - Superior orbital fissure; V2 - foramen Rotundum; V3 - foramen Ovale; Think: "divisions of CN V exit owing to Standing Room Only"

Question 40

Through what structure does the Middle meningeal artery travel?

Answer 40

Foramen spinosum (Middle meningeal artery)

Question 41

Which CN's travel through Posterior cranial fossa? More specifically, through what other structure(s) do they travel?

Answer 41

Posterior cranial fossa (CN VII-XII) - through temporal or occipital bone

Question 42

Through which structure does CN VII travel? What other CN also passes through this structure?

Answer 42

Posterior cranial fossa (CN VII-XII) - through temporal or occipital bone: Internal auditory meatus (CN VII, VIII)

Question 43

Through which structure does CN IX travel? What other CN's also pass through this structure? What vessel passes through this structure as well?

Answer 43

Posterior cranial fossa (CN VII-XII) - through temporal or occipital bone: Jugular foramen (CN IX, X, XI, jugular vein)

Question 44

Through which structure does CN XII travel?

Answer 44

Posterior cranial fossa (CN VII-XII) - through temporal or occipital bone: Hypoglossal canal (CN XII)

Question 45

What 3 structures travel through the Foramen magnum?

Answer 45

Posterior cranial fossa (CN VII-XII) - through temporal or occipital bone: Foramen magnum (spinal roots of CN XI, brain stem, vertebral arteries)