Cranial nerve nuclei
Completing this study unit will allow you to:
- Name and group the cranial nerve nuclei of the brainstem.
- Describe the location of each cranial nerve nuclei.
- Identify cranial nerves associated with each cranial nerve nucleus.
- Learn the main functions of each cranial nerve nuclei.
The cranial nerve nuclei are collections of cell bodies dispersed throughout the brainstem. They function to either receive afferent inputs from cranial nerve fibers or give off efferent outputs which travel along the cranial nerves to target structures.
The cranial nerve nuclei can be divided into 7 different modalities based on the information they carry to and from their target tissues, impulse type and specificity or exclusivity to cranial nerves:
- General somatic efferent (GSE): skeletal muscles of the head and neck (e.g. extraocular muscles and muscles of the tongue).
- General visceral efferent (GVE): smooth muscles of gut and autonomic motor (e.g. smooth muscles of the salivary glands and iris sphincter muscle and the ciliary muscle.
- Special visceral efferent (SVE): muscles derived from pharyngeal arches, specific to cranial nerves.
- General somatic afferent (GSA): general sensation from skin.
- General visceral afferent (GVA): general sensation from viscera.
- Special somatic afferent (SSA): senses derived from ectoderm, specific to cranial nerves (e.g. sight, sound, balance).
- Special visceral afferent (SVA): senses derived from endoderm, specific to cranial nerves (e.g. taste, smell).
It is important to note that while cranial nerves can carry a mixture of both motor and sensory fibers, cranial nerve nuclei can only be motor or sensory. Therefore, cranial nerves may arise from more than one nucleus and some cranial nerves may even share the same nucleus.
The olfactory nerve (CN I) and the optic nerve (CN II) arise outside the brainstem and therefore, are the only cranial nerves which do not communicate with cranial nerve nuclei. The spinal accessory nerve (CN XI), while it does not originate from the brainstem, maintains communication with a cranial nerve nucleus via its cranial rootlets.
Find out more about the afferent and efferent cranial nerve nuclei by watching the video below.
Take a quiz
Well, that was a lot of information! Test your knowledge on the cranial nerve nuclei with the quiz below.
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Take a look at the atlas galleries below to explore cranial nerve nuclei from anterior and lateral perspectives.
|Oculomotor nerve (CN III)||Nucleus of oculomotor nerve (GSE), accessory nucleus of oculomotor nerve (GVE)|
|Trochlear nerve (CN IV)||Nucleus of trochlear nerve (GSE)|
|Trigeminal nerve (CN V)||Motor nucleus of trigeminal nerve (SVE), principal nucleus of trigeminal nerve (GSA), spinal nucleus of trigeminal nerve (GSA)|
|Abducens nerve (CN VI)||Nucleus of abducens nerve (GSE)|
|Facial nerve (CN VII)||Nucleus of facial nerve (SVE), superior salivatory nucleus (GVE), nucleus of solitary tract (GVA, SVA), spinal nucleus of trigeminal nerve (GSA)|
|Vestibulocochlear nerve (CN VIII)||Cochlear nuclei (SSA), vestibular nuclei (SSA)|
|Glossopharyngeal nerve (CN IX)||Nucleus ambiguus (SVE), inferior salivatory nucleus (GVE), nucleus of solitary tract (GVA, SVA), spinal nucleus of trigeminal nerve (GSA)|
|Vagus nerve (CN X)||Posterior nucleus of vagus nerve (GVE), nucleus ambiguus (SVE), nucleus of solitary tract (SVA, GVA), spinal nucleus of trigeminal nerve (GSA)|
|Accessory nerve (CN XI)||Nucleus ambiguus (SVE)|
|Hypoglossal nerve (CN||Nucleus of hypoglossal nerve (GSE)|
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