Cranial Nerves

Question 1

Cranial Nerve 1

Answer 1

OLFACTORY NERVE

• Located in the forebrain
• Runs through cribriform plate of ethmoid bone
• Primarily sensory
• Visceral Sensory: Smell

Question 2

Cranial Nerve 2

Answer 2

OPTIC NERVE

• Located in the forebrain
• Runs through canal of orbit
• Primarily sensory
• Somatic sensory of vision

Question 3

Cranial Nerve 3

Answer 3

OCULOMOTOR NERVE

• Located in the midbrain
• Runs through superior orbital fissure
• Primarily somatic motor, some visceral motor

Question 4

Cranial Nerve 4

Answer 4

TROCHLEAR NERVE

• Located in the midbrain
• Runs through superior orbital fissure
• Primarily somatic motor

Question 5

Cranial Nerve 5

Answer 5

TRIGEMINAL NERVE
-Located in the pons
-Largest cranial nerve, for chewing
-Mixed motor and sensory
Three Divisions:
1.Ophthalmic Division - runs thru superior orbital fissure
2. Maxillary Division - runs thru foramen rotundum
3. Mandibular division - runs through foramen ovale

Question 6

Cranial Nerve 6

Answer 6

ABDUCENS NERVE

• Located in pons
• Abducts the eyeball by innervation of lateral rectus muscle
• Exclusively motor
• Runs through superior orbital fissure

Question 7

Cranial nerve 7

Answer 7

FACIAL NERVE

• Located in pons, enters temporal bone via internal acoustic meatus
• Chordi tympani branch (taste) runs through stylomastoid foramen
• Mixed motor/sensory

Question 8

Cranial Nerve 8

Answer 8

VESTIBULOCOCHLEAR NERVES

• Sensory nerve of hearing and balance
• Passes through internal acoustic meatus and enters into inner ear of temporal lobe
• Primarily sensory, some motor

Question 9

Cranial Nerve 9

Answer 9

GLOSSOPHARYNGEAL NERVE

• Innervates structures of the tongue and pharynx
• runs thru jugular foramen
• Mixed motor and sensory

Question 10

Cranial Nerve 10

Answer 10

VAGUS NERVE

• Parasympathetic innervation of organs
• runs thru jugular foramen
• mixed motor and sensory

Question 11

Cranial Nerve 11*

Answer 11

ACCESSORY NERVES

• Unique among cranial nerves
• Formed from ventral rootlets of spinal cord (C1-C5) so has features of both cranial and spinal nerves
• Do NOT arise from brainstem
• Enters the skull as accessory nerve thru foramen magnum and exit skull thru juglar foramen and innervates trapezius and sternocleidomastoid muscles
• Exclusively motor

Question 12

Cranial Nerve 12

Answer 12

HYPOGLOSSAL NERVES

• Innervates tongue muscles
• Runs through hypoglossal canal, inferior to tongue
• Primarily motor

Question 13

Baroreceptors

Answer 13

Mechanoreceptors that monitor blood pressure

Question 14

2 types of thermoreceptors

Answer 14

Capsaicin receptors (hot receptors)
Menthol receptors (cold receptors)

Question 15

Unencapsulated nerve endings

Answer 15

• Free nerve endings

- Include epithelial tactile complexes (Merkel discs) and hair follicle receptors

Question 16

Encapsulated nerve endings

Answer 16

• Tactile corpuscles (Meissner’s corpuscles)… for discriminative tough and low freq. vibration of fingertips, nipples, and external genitalia
• Lamellar corpuscles (Pacinian corpuscles)…. in hypodermis, dermir, tendons… deep pressure, stretch, high freq. vibration
• Bulbous corpuscles (Ruffini endings)… similar to pacinian
• Proprioceptors: Monitor stretch of locomotor organs