Cranial Nerves

Question 1

How many cranial nerves are there?

Answer 1

12 labelled I-XII

Question 2

What’s the difference between cranial nerves and spinal nerves?

Answer 2

Cranial nerves don’t have dermatomal or myatomal distribution. Each cranial nerve serves different functions in the head and neck. And cranial nerves supply special senses. (Sight, taste, hearing, smell and balance).

Question 3

What is cranial nerve I and it’s function?

Answer 3

Olfactory nerve

Special sense. Afferent from nasal mucosa, carries information related to smell.

Question 4

What is CNII and what’s it’s function?

Answer 4

Optic nerve

Special sense. Afferent for vision from the retina.

Question 5

What is CNIII and it’s function?

Answer 5

Oculomotor nerve
Somatic division controls movement of the eye and some control of eyelid. Autonomic division is motor to pupil constrictors.

Question 6

What is CNIV and it’s function?

Answer 6

Tochlear

Somatic: motor to one muscle that moves the eye.

Question 7

What is CNV and it’s function?

Answer 7

Trigemonal
Somatic: Afferent from surface of face- senses touch from skin of face and cornea (dermatomes of face)
Motor efferent to muscles of mastication (myotomes)

Question 8

What is CNVI and it’s function?

Answer 8

Abductent

Somatic: motor efferent to one muscle of the eye

Question 9

What is CNVII and it’s function?

And what disease is linked to it?

Answer 9

Special sense: taste from anterior tongue and palate.
Somatic division: motor efferent to muscles of facial expression (myotomes)
Autonomic division: motor efferent to glands that secrete saliva.
Bell’s palsy is the disease linked to it.

Question 10

What is CN8 and it’s function?

Answer 10

Vesribulocochlear nerve
Special sense: hearing from cochlea of ear.
Balance from vestibular apparatus of ear

Question 11

What is CNIX and it’s function?

Answer 11

Glossopharyngeal nerve
Special sense: taste from posterior tongue
Somatic division: motor efferent to help with swallowing.
Afferent sensation from external ear
Autonomic division: secretomotor to one saliva gland
Afferent sensation from carotid body and sinus

Question 12

What is CNX and it’s function?

Answer 12

Vagus nerve
Somatic division: motor to muscles of pharynx, larynx and palate.
Autonomic division: parasympathetic inner sti on of smooth muscle in trachea, bronchi, GI tract and cardiac muscle
Afferent sensation from GI tract, heart and airways.

Question 13

What is CNIX and it’s function?

Answer 13

Accessory nerve

Somatic: motor to soft palate pharynx and to two big muscles in the neck.

Question 14

What is CNXII and it’s function?

Answer 14

Hypoglossal

Somatic: motor to the muscles of the tongue.