BRAIN STEM: CRANIAL NERVES

Name the 12 cranial nerves

I. Olfactory	IV. Trochlear	VII. Facial	X. Vagus
II. Optic	V. Trigeminal	VIII. Auditory	XI. Spinal accessory
III. Oculomotor	VI. Abducens	IX. Glossopharyngeal	XII. Hypoglossal

What are general somatic afferent nerves? Which cranial nerves carry them?

General somatic afferent fibers carry exteroceptive (pain, temperature, touch) and 
proprioceptive impulses. Cranial nerves for proprioception: III, IV, V, VI, XII; for pain, 
temperature, and touch: V, VII, IX, X.

 

What are general visceral afferent nerves? Which cranial nerves carry them?

General visceral afferent fibers carry impulses from the visceral structures, and 
cranial nerves IX and X contain these fibers.

 

What are special somatic afferent nerves? Which cranial nerves carry them?

Special somatic afferent fibers carry sensory impulses from the special senses
(vision, hearing, equilibrium), and cranial nerves II and VIII contain these fibers.

 

What are special visceral afferent nerves? Which cranial nerves carry them?

Special visceral afferent fibers carry impulses from the olfactory and gustatory 
senses, and cranial nerves I (olfactory) and VII, IX, and X (gustatory) contain 
these fibers.

 

What are general somatic efferent nerves? Which cranial nerves carry them?

General somatic efferent fibers carry motor impulses to somatic skeletal muscles. 
In the head, the tongue and extraocular muscles are of this type. Cranial nerves 
III, IV, VI, and XII carry these fibers.

 

What are general visceral efferent nerves? Which cranial nerves carry them?

General visceral efferent fibers carry parasympathetic autonomic axons. The
following cranial nerves carry general visceral efferent fibers:

1. Cranial nerve III (Edinger-Westphal nucleus): the preganglionic fibers from the 
Edinger-estphal nucleus terminate in the ciliary ganglion, and the postganglionic
fibers innervate the pupil.

2. Cranial nerve VII (superior salivatory nucleus): the preganglionic fibers from the 
superior salivatory nucleus terminate in the pterygopalatine and submandibular 
ganglion. The postganglionic fibers innervate the lacrimal gland (from the 
pterygopalatine ganglion) and the submandibular and sublingual gland (from 
the submandibular ganglion).

3. Cranial nerve IX (inferior salivatory nucleus): the preganglionic fibers from the inferior 
salivatory nucleus terminate in the otic ganglion, and the postganglionic fibers innervate 
the parotid gland.

4. Cranial nerve X (dorsal motor nucleus): the dorsal motor nucleus innervates the abdominal
 viscera.

 

What are special visceral efferent nerves? Which cranial nerves carry them?

 

Special visceral efferent fibers innervate skeletal muscle derived from the branchial arches.
 Cranial nerves V (muscles of mastication, first branchial arch), VII (muscles of facial expression, 
second branchial arch), IX (stylopharyngeus muscle, third branchial arch), X (muscles of the 
soft palate and pharynx, fourth branchial arch), and XI (muscles of the larynx/sternocleidomastoid 
(SCM)/trapezius, sixth branchial arch) carry them.