1. Cranial and spinal nerves
Domina Petric, MD

2. Cranial nerves I.

3. Olfactory nerve (I.): sense of smell
It is a set of fine axons that run from the nasal epithelium to the olfactory bulb so it is not really a nerve, but part of the brain.
Those axons run through the ethmoid bone (cribriform plate).

4. Optic nerve (II.): vision
Grows out from retinal ganglion cells (inner layer of the retina).
Two optic nerves make optic chiasm.
It is part of the brain.

5. Oculomotor nerve (III.): eye movements, pupillary constriction and accommodation; muscles of eyelid
Emerges from the interpeduncular fossa in the midbrain (mesencephalon).
Somatic motor component innervates muscles of the eyeball (not all of them) and muscle that elevates the eyelid.
Visceral motor component is parasympathetic preganglionic outflow that is involved in constricting the pupil.

6. Trochlear nerve (IV.): eye movements (intorsion, downward gaze)
Emerges from the dorsal aspect of the brain stem (midbrain).
It is only cranial nerve that exits on the dorsal side of the central nervous system.
It has only somatic motor outflow that innervates superior oblique muscle of the eyeball (inward and downward gaze).

7. Only nerve emerging from the ventro-lateral aspect of the pons.
Trigeminal nerve (V.): motor and sensory, somatic sensation from face, mouth and cornea; muscles of mastication
Only nerve emerging from the ventro-lateral aspect of the pons.
Branchial motor component is for muscles of mastication.
General somatic sensory component for somatic sensation from face, mouth and cornea.

8. Abducens nerve (VI.): eye movements (abduction or lateral movements)
Emerges from the junctional region between pons and medulla oblongata, close to the midline.
Single somatic motor output for lateral rectus muscle of the eyeball.

9. Facial nerve (VII.): controles the muscles of facial expression, taste from anterior tongue, lacrimal and salivary glands
Emerges from the junctional region between pons and medulla oblongata.
Branchial motor component supplies the muscles of facial expression.
Parasympathetic outflow for the numerous glands in the cranial region: lacrimal and salivary glands (exept for the parotid gland).
Special visceral outflow (sense of taste) from anterior two thirds of the tongue.
General somatic sensory component: small patch of skin in the ear.

10. Vestibulocochlear nerve (VIII.): hearing, sense of balance
Emerges from the junctional region between pons and medulla oblongata.
It is the most lateral nerve emerging from the junctional region.
Special sensory nerve: hearing (cochlea) and sense of balance (labyrinth).

11. Glossopharyngeal nerve (IX
Glossopharyngeal nerve (IX.): sensation from posterior tongue and pharynx, taste from posterior tongue, carotid baroreceptors and chemoreceptors
Emerges from the medulla oblongata.
Branchial motor component for the innervation of the muscles around the pharynx.
Parasympathetic outflow for the parotid gland.
Special visceral sense of taste from the posterior one third of the tongue.
General visceral sensory output from the carotid bodies which are important for regulating blood pressure, cardiac output and respiration rate.
Somatic sensory component: small patch of skin from the external ear.

12. Vagus nerve (X.): autonomic functions of gut, sensation from larynx and pharynx, muscles of vocal cords, swallowing
Emerges from the medulla oblongata.
Branchial motor component provide innervation to muscles of the posterior pharynx and the region of the larynx.
Parasympathetic outflow for the viscera in the thorax and in the upper part of the abdomen.
Special visceral sensation of taste from some taste buds in the posterior part of the oral cavity.
Visceral sensory signal for regulation of cardiovascular system (aortic arch).
Somatic general sensory innervation to a patch of skin around the external auditory meatus.

13. Spinal accessory nerve (XI.): shoulder and neck muscles
Emerges from the medulla oblongata.
Branchial motor output for the upper part of the trapezius muscle and the sternocleidomastoid muscle.

14. Hypoglossal nerve (XII.): movements of tongue
Emerges from the medulla oblongata, between medullary pyramid and olive.
Somatic motor output for tongue muscles.

15. Cranial nerves
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16. Cranial nerves nuclei in the brain stem
4 somatic motor nuclei
4 branchial motor nuclei
4 parasympathetic motor nuclei
4 sensory nuclei

17. Trochlear nerve nucleus Abducens nucleus Hypoglossal nucleus
Somatic motor nuclei
Oculomotor nucleus
Trochlear nerve nucleus
Abducens nucleus
Hypoglossal nucleus

18. Branchial motor nuclei
Trigeminal motor nucleus
Facial nucleus
Nucleus ambiguus (IX. and X.)
Accessory nucleus

19. Parasympathetic nuclei
Endinger Westphal nucleus (III.)
Salivatory nuclei (VII. and IX.)
Nucleus ambiguus (IX. and X.)
Dorsal motor nucleus of vagal nerve (XI. and XII.)

20. Sensory nuclei
Nucleus of the solitary tract for special visceral and general visceral sensation (VII., IX. and X.): rostral division is for the taste and caudal division for visceral sensation.
Trigeminal nuclear complex for the somatic (general) sensory output (V., VII., IX. and X.): mechano-sensation, pain and temperature sensitivity.
Cochlear nucleus
Vestibular nucleus

21. Cranial nerve nuclei
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22. Spinal nerves
II.

23. 31 Spinal nerves 8 pairs of cervical nerves
12 pairs of thoracic nerves
5 pairs of lumbar nerves
5 pairs of sacral nerves
1 coccygeal nerve

24. Two spinal enlargements: motor and sensory output
cervical enlargement (arms)
lumbosacral enlargement (legs)

25. Cauda equina (horses tail)
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26. Spinal roots
Ventral root is a motor root and sends signals to striated muscles.
Dorsal root is a sensory root.
BUT spinal nerves can be mixed nerves, with motor and sensory axons.

28. Chain of ganglia that runs the long axis.
Sympathetic chain
Chain of ganglia that runs the long axis.
In these ganglia are the neurons that innervate viscera, basically everywhere where is sympathetic innervation of smooth muscle or cardiac muscle or glandular tissue.

29. Literature
neuroscience/lecture: Leonard E. White, PhD, Duke university.
TeachMeAnatomy. Com

30. Literature