Sensory

Visceral Afferent

(SVA)

(olfactory)

-sense of smell (olfaction)

Consists of axons whose cell bodies are in
olfactory epithelium;

axons pass into
cranial cavity through the cribriform plate
of the ethmoid bone and synapse on the
olfactory bulbs and then are continued
caudally by the olfactory tract. Enclosed
within meninges as they enter the skull.

(Optic)

Regarded as a brain tract connecting the
retina to diencephalon. Axons from
ganglion cells in the retina form optic n.
Caudal to the orbit some of the fibres of
each nerve cross to the other side at the
optic chiasm (decussate) before entering
the brain. Enclosed within extensions of
the meninges.

(optic)

sensory

somatic afferent (SSA)

(optic)

sight

(oculomotor)

motor

somatic efferent (GSE)

visceral effererent (GVE)

(oculomotor)

Muscles that move the eyeball and control pupil diameter
Dorsal, medial and ventral recti, ventral
oblique, m. levator of upper eyelid.
Intraocular ciliary and constrictor pupillae
muscles

(Trochlear)

Nucleus in midbrain (tegmentum).
Nerve fibres cross over within the brain
and emerge dorsally and exit cranial cavity
through orbital fissure

(Trochlear)

motor

Somatic Efferent (GSE)

(Trochlear)

dorsal oblique of the eyeball

(Trigeminal)

Sensory nuclei located from mid-brain to
spinal cord; the motor nucleus is found in
the pons. Leaves the brain stem at
pons/trapezoid body junction and reaches
the trigeminal ganglion.

(Trigeminal)

mixed

somatic afferent

somatic efferent

(Trigeminal)

sensory for skin and deep structures of the face

motor to muscles of mastication

(Abducent)

Nucleus in medulla oblongata. Exits skull
through orbital fissure.

(Abducent)

motor

somatic efferent

(Abducent)

mm rectus latalis; part of retractor bulbi

(Facial)

Nuclei in medulla oblongata.

Emerges from the brain at the trapezoid body, exits
cranial cavity through internal acoustic meatus and passes through facial canal in the temporal bone and then out the caudal part of the skull (stylomastoid foramen).

Sensory ganglion is in the facial canal

(Facial)

mixed (gustatory and parasympathetic functions)

somatic efferent

visceral efferent

visceral afferent

(facial)

motor (eg facial expression and ears)

salivary glands (mandibular, sublingual), lacrimal, nasal and palatine glands

sensory-taste from rostral 2/3 of tongue

(Vestibulocochlear)

Vestibulocochlear apparatus is in the inner ear. The nerve leaves bone via internal acoustic meatus to enter the medulla oblongata close to the trapezoid body.
Primary sensory cells are in ganglia close
to the CNS.
Vestibular nuclei are located in the pons and medulla oblongata.

(Vestibulocochlear)

sensory

somatic afferent

(Vestibulocochlear)

hearing and balance

(Glossopharyngeal)

nuclei in medulla oblongata

leaves cranial cavity through jugular foramen

(glossopharyngeal)

mixed

somatic efferent

visceral efferent

visceral afferent

(Glossopharyngeal)

soft palate, pharynx, parotid and zygomatic salivary glands

oral and pharyngeal mucosa including for taste

(caudal 1/3 of tongue), carotid body and sinus

(Vagus)

Two sensory ganglia (receptors in viscera).
Motor nuclei in medulla oblongata.
Passes out of cranial cavity through jugular foramen; passes down the neck with the sympathetic trunk (forming vagosympathetic trunk); separates at the thoracic inlet and continues through mediastinum. Divides into dorsal and ventral vagal trunks → abdomen where it has many branches that with the
sympathetic fibres form the plexuses
supplying the abdominal viscera.

(Vagus)

Mixed

Visceral afferent

Visceral efferent

Somatic efferent

(Vagus)

VA for: Pharynx, epiglottis (taste), larynx,
trachea, oesophagus, thoracic and
abdominal viscera

VE for: Musculature of pharynx and larynx, viscera of thorax and
abdomen
SE for: Motor for muscles of pharynx, larynx,
oesophagus

(Accessory)

Made up of two roots. Spinal root (usually referred to as accessory nerve) is formed by fibres emerging from cervical spinal cord which run cranially to enter cranial
cavity through the foramen magnum and briefly joins the cranial root.
Cranial root: nucleus is in the medulla oblongata. Joins with CN X (fibres to laryngeal musculature).
Accessory nerve passes back out of cranial cavity through jugular foramen, turns caudally and divides into dorsal and ventral branches.

(Accessory)

Motor

Somatic efferent

(accessory)

motor to muscles of neck and shoulder

(Hypoglossal)

Nucleus in medulla Oblongata; leaves ventral aspect of medulla oblongata and exits cranial cavity through hypoglossal formen

(Hypoglossal)

motor

somatic efferent

(hypoglossal)

motor to muscles of tongue

(parasympathetic)

CN III, VII, IX, X