Neuroanatomy (Cranial Nerve Terms)

Question 1

What are the 6 functional components of cranial nerves?

Answer 1

General somatic afferent, General visceral afferent, Special afferent, General somatic efferent, General visceral efferent, Special efferent

Question 2

What is the function of GSA and what nerves have this component?

Answer 2

Perception of touch, pain and temperature. Trigeminal nerve (5), Facial nerve (7), Glossopharyngeal (9) and Vagus (10)

Question 3

What is the function of GVA and what nerves have this component?

Answer 3

Sensory input from viscera. Glossopharyngeal (9) and Vagus (10)

Question 4

What is the function of SA and what nerves have this component?

Answer 4

Smell, taste, vision, hearing and balance. Olfactory (1), Optic (2), Facial (7), Vestibulocochlear (8), Glossopharyngeal (9) and Vagus (10)

Question 5

What is the function of GSE and what nerves have this component?

Answer 5

Motor innervation to skeletal muscles (voluntary). Oculomotor (3), Trochlear (4), Abducens (6) and Hypoglossal (12)

Question 6

What is the function of GVE and what nerves have this component?

Answer 6

Motor innervation to smooth muscles, heart muscles and glands. Oculomotor (3), Facial (7), Glossopharyngeal (9) and Vagus (10)

Question 7

What is the function of SE and what nerves have this component?

Answer 7

Motor innervation to skeletal muscles derived from pharyngeal arch mesoderm. Trigeminal (5), Facial (7), Glossopharyngeal (9), Vagus (10) and Accessory nerve (11)

Question 8

Name and describe what functional components cranial nerve 1 has, where it exits skull and function

Answer 8

Olfactory nerve has SA fibers, receptors for which are found in the roof and upper part of nasal cavity. Exits the skull from the cribiform plate in the ethmoid bone. Function is smell.

Question 9

Name and describe what functional components cranial nerve 2 has, where it exits skull and function

Answer 9

Optic nerve has SA fibers for vision and photoreceptors found in the retina. Exits cranial cavity through optic canal.

Question 10

Name and describe what functional components cranial nerve 3 has, where it exits skull and function

Answer 10

Oculomotor nerve has GSE and GVE functions. GSE innervates extraocular muscles while GVE carries parasympathetic fibres for structures in the orbit. Exits skull from superior orbital fissure.
GSE: innervates levator palpebrae superioris, superior rectus, inferior rectus, medial rectus and inferior oblique muscles.
GVE: sphincter pupillae for pupillary constriction, ciliary muscles for accommodation of near vision

Question 11

Name and describe what functional components cranial nerve 4 has, where it exits skull and function

Answer 11

Trochlear nerve has GSE functions to innervate superior oblique muscle. Exits skull from superior orbital fissure.

Question 12

Name and describe what functional components cranial nerve 5 has, where it exits skull and function

Answer 12

Trigeminal nerve has GSA and branchial efferent functions. Has three divisions:
1. Ophthalmic division which exits skull through superior orbital fissure
2. Maxillary division which exits skull through foramen rotundum
3. Mandibular division which exits skull through foramen ovale
GSA fibres innervate sensation from most of head while BE innervates mainly muscles of mastication in the jaw.

Question 13

Name and describe what functional components cranial nerve 6 has, where it exits skull and function

Answer 13

Abducent nerve has GSE fibres which innervate lateral rectus muscle and exit cranial cavity through superior orbital fissure.

Question 14

Name and describe what functional components cranial nerve 7 has, where it exits skull and function

Answer 14

Facial nerve has GSA and SA functions as well as GVE and BE functions. Exits cranial cavity through internal acoustic meatus and skull through stylomastoid foramen.
GSA - sensory from part of external acoustic meatus and deeper parts of auricle
SA - taste from anterior 2/3 of tongue
GVE - innervates lacrimal gland, submandibular and sublingual salivary glands and mucous membranes of nasal cavity plus hard and soft palates.
BE - innervates muscles of face and scalp derived from second pharyngeal arch and stapedius, posterior belly of digastric and stylohyoid.

Question 15

Name and describe what functional components cranial nerve 8 has, where it exits skull and function

Answer 15

Vestibulocochlear has SA fibres for hearing and balance where vestibular division is for balance and cochlear division is for hearing. Exits cranial cavity through internal acoustic meatus and enters ear.

Question 16

Name and describe what functional components cranial nerve 9 has, where it exits skull and function

Answer 16

Glossopharyngeal nerve has GSA, GVA and SA fibres as well as GVE and BE. Exits cranial cavity through jugular foramen.
GVA - sensation from carotid body and sinus
GSA - posterior 1/3 tongue, tonsils, mucosa of middle ear and pharyngotympanic tube
SA - taste from posterior 1/3 of tongue
GVE - innervates parotid salivary gland
BE - innervates stylopharyngeous muscle

Question 17

Name and describe what functional components cranial nerve 10 has, where it exits skull and function

Answer 17

Vagus nerve has GSA, GVA and SA fibres as well as GVE and BE.
GSA - sensory input from some of ear and surrounding area plus dura in posterior cranial fossa.
GVA - sensory from aortic body chemoreceptors, aortic arch baroreceptors, pharynx, larynx, neck, other organs of thorax, foregut and midgut.
SA - taste around epiglottis
GVE - parasympathetic innervation of pharynx, larynx, thorax, foregut and midgut
BE - innervate muscles associated with tongue, soft palate, pharynx and larynx.
Exits cranial cavity through jugular foramen.

Question 18

Name and describe what functional components cranial nerve 11 has, where it exits skull and function

Answer 18

Accessory nerve has BE fibres to innervate sternocleidomastoid and trapezius muscle. Roots arise from upper 5 segments of cervical spinal cord. Enter cranial cavity through foramen magnum and exit through jugular foramen.

Question 19

Name and describe what functional components cranial nerve 12 has, where it exits skull and function

Answer 19

Has GSE fibres and innervates all intrinsic muscles of tongue and all but one extrinsic muscle. Exits the cranial cavity through the hypoglossal canal.