Cranial Nerves (Pre-Study)

Question 1

T or F: cranial nn. are a part of the peripheral nervous system

Answer 1

True

Question 2

Which cranial nerves originate within the cranial cavity?

Answer 2

• All except XI

Question 3

T or F: like spinal nerves, cranial nerves are all similar in function.

Answer 3

False

Question 4

What cranial nerves are sensory only?

Answer 4

I, II, and VIII

Question 5

What cranial nerves are motor only?

Answer 5

III, IV, VI, XI, and XII

Question 6

What cranial nerves are mixed?

Answer 6

V, VII, IX, X

Question 7

Where are the cell bodies for sensory cranial nerves located?
- Cell type?

Answer 7

• In sensory ganglia

- Pseudounipolar

Question 8

What four cranial nerves provide the distribution of the cranial division of the parasympathetic nervous system?

Answer 8

III, VII, IX, and X

Question 9

What is the composition of the sympathetic distribution in the head?

Answer 9

• Postganglionic Fibers from Superior Cervical Ganglion

- These travel on Internal and External Carotid arteries and their branches

Question 10

T or F: cranial nerves form by the fusion of dorsal and ventral roots like spinal nerves.

Answer 10

False, motor and sensory fibers of cranial nerves are fused as they exit the brain

Question 11

What do special sensory nerves sense and which cranial nerves have special sensory components?

Answer 11

• Vision, Hearing, Equilibrium, Taste, and Smell

- CNs I, II, VII, VIII, IX, X

Question 12

Where are GSE fibers in the head (to skeletal muscle) derived from?

Answer 12

• Somite Mesoderm

Question 13

T or F: most sympathetic GVE fibers travel with the cranial nerves

Answer 13

False, they go to their targets by following internal and external carotids and their branches

Question 14

What is BE (Branchiomeric) innervation?

Answer 14

• Motor innervation to skeletal muscle in the head derived from branchial (PHARYNGEAL arch) mesoderm

Question 15

Where do sympathetic fibers to the head and neck come from and how do they get to their target?

Answer 15

Origin of Preganglionic Cell Bodies:
-Come from Lateral Horn of T1-T2

Preganglionic Path and Synapse:
- Ascend on sympathetic chain to Superior Cervical Ganglion and synapse with postganglionic neurons IN CHAIN GANGLIA

Postganglionic Path:
- Postganglionic fibers leave the sympathetic chain and form Carotid Periarterial Plexus to distribute to the head

Question 16

Which Cranial Nerves have Sensory Function only and what do they do?

Answer 16

**All Special Afferent (SA) fibers

• CN I (olfactory) - olfaction (smell)
• CN II (Optic) - Vision (sight)
• CN VIII (vestibulocochlear) - Audition (hearing) and Equilibrium (Balance)

Question 17

Which 5 Cranial Nerves have Motor Function only and what do they do?

Answer 17

CN III (occulomotor)

• GSE, Motor to 5 extraocular muscles
• *GVE, parasympathetic motor to sphincter pupillae and ciliary muscles

CNIV (trochlear)
- GSE, Motor to 1 Extraocular muscle (superior oblique)

GNVI (Abducent)
- GSE, Motor to 1 Extraocular muscle (Lateral Rectus)

CNXI (Accessory)
- GSE, Motor to Trapezius and Sternocleidmastoid Muscles

GNXII (Hypoglossal)
- GSE:
Motor to 3 EXtrinsic Muscles of the tongue
Motor to ALL INtrinsic muscles of the tongue