Cranial nerves: parasympathetic function

Question 1

What cranial nerves have a parasympathetic function|?

Answer 1

3, 7, 9 and 10

Question 2

What do sympathetic preganglionic neurons enter the sympathetic trunk via?

Answer 2

White ramus communicantes (WRC)

Question 3

What do postanganglionic sympathetic fibres exit the sympathetic cord via?

Answer 3

Form the grey ramus communicantes that joins a spinal nerve in which it is distributed to the body wall

Question 4

What does each sympathetic trunk extend between?

Answer 4

The atlas and coccyx

Question 5

What do the 2 sympathetic trunks fuse to form?

Answer 5

The ganglion impar (opposite the coccyx)

Question 6

What are the sympathetic cervical ganglia?

Answer 6

• Superior (C1-4)
• Middle (C5-6)
• Inferior (C7-8) cervical ganglia
• Stellate ganglion(cervicothoracic) -> Inferior cervical + T1

Question 7

What make up the cervicothoracic/stellate ganglion?

Answer 7

C7-T1 cervical ganglia (inferior cervical + T1)

Question 8

Where do sympathetics reaching the eye originate?

Answer 8

T1-2 ciliospinal centre

Question 9

Where do sympathetic pre-ganglionic neurons to the eye synapse?

Answer 9

Superior cervical ganglion

Question 10

What do post-gnaglionic sympathetic fibres to the eyes form a plexus around?

Answer 10

Internal carotid artery (enter into cranial cavity through this road - they then hitchhike with cranial nerves and their branches)

Question 11

Sympathetics which go to Dilator papilla muscle are carried by what nerve?

Answer 11

Nasociliary nerve -> long ciliary nerve

Question 12

What is the nasociliary nerve a branch of?

Answer 12

Opthalmic nerve

Question 13

What does the oculomotor nerve supply?

Answer 13

Levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique muscles

Question 14

What are the symptoms of HOrner’s syndrome?

Answer 14

• Ptosis - drooping of upper eyelid
• Pupillary constriction (miosis)
• Anhydrosis (lack of sweating)
• Flushing of the face
  Results of unapposed parasympathetic activity

Question 15

How many neurons are in the parasympathetic chain?

Answer 15

2 neuron chain

Question 16

Where do the pre-ganglionic neurons in the CNS synapse?

Answer 16

In a ganglion with a post-ganglionic neuron

Question 17

Where are the parasympathetic ganglia located?

Answer 17

Close to the organ -> long pre-synaptic fibres and short post-synaptic fibres

Question 18

What cranial nerves have parasympathetic output?

Answer 18

• CN III - Oculomotor
• CN VII - Facial
• CN IX - Glossopharyngeal
• CN X - Vagus

Question 19

What are the functions of the parasympathetic fibres from cranial nerves?

Answer 19

• Salivary glands
• Lacrimal glands
• Certain structures in eye

Question 20

What is the nucelus for the oculomotor nerve?

Answer 20

• Autonomic nucleus (Edinger-Westphall)

- Midbrain

Question 21

Where does the autonomic nucleus receive afferents from?

Answer 21

• Receives afferents from cortex and pretectal nucleus, bilaterally

Question 22

Where does oculomotor nerve travel?

Answer 22

• Lateral wall of cavernous sinus (with motor fibres)

- Pass through superior orbital fissure and enter orbit

Question 23

In the orbit what does the oculomotor nerve divide into?

Answer 23

• Superior and inferior divisions pass through common tendinous ring of Zinn but only inferior division contain parasympathetics

Question 24

What does the superior ramus of the oculomotor nerve contain?

Answer 24

Motor fibres from oculomotor nucleus + sympathetic fibres from superior cervical ganglion to levator palpebra superioris

Question 25

What does the inferior ramus of the oculomotor nerve contain?

Answer 25

Parasympathetic fibres

Question 26

Where do parasympathetic fibres of the oculomotor nerve synapse?

Answer 26

Ciliary ganglion

Question 27

What do postsynaptic oculomotor nerve fibres join?

Answer 27

Short ciliary nerves

Question 28

What do short ciliary nerves run alongside?

Answer 28

Long ciliary nerves and ciliary artery

Question 29

What does the oculomotor nerve supply?

Answer 29

- Ciliary muscle | - Sphincter pupilla

Question 30

What is the lamina cribrosa sclerae?

Answer 30

Mesh like structure on the posterior aspect of eyeball around optic nerve. Arteries and veins pierce this area

Question 31

What reflex can test the function of the oculomotor nerve?

Answer 31

Light reflex

Question 32

What is the consensual light reflex?

Answer 32

Light that is directed in one eye produces pupil constriction in both eyes

Question 33

What is the pretectal nucleus connected to and how does this relate to the consensual light reflex ?

Answer 33

- Certain optic nerve fibres terminate on pretectal nucleus - Pretectal nucleus then connects to parasympathetic nucleus of oculomotor (edinger-Westphal) on both sides - Allows for constiction in both eyes by parasympathetic fibres reaching both ciliary ganglia and both short ciliary nerves - Will cause pupillary constrictor muscle to contract on both sides

Question 34

What does injury to the oculomotor nerve result in?

Answer 34

- No parasympathetic input for pupil constriction -> dilated pupil - Loss of motor innervation to levator palpebrae superioris -> Ptosis - Loss of motor innervation to extraocular muscles except superior oblique (trochlear nerve) and lateral rectus (abducent nerve) -> eye turns downwards and outwards

Question 35

Where do the parasympathetic secretorymotor fibres of the facial nerve go to?

Answer 35

- Lacrimal gland - Glands in nasal and oral cavities - Submandibular and sublingual salivary glands

Question 36

Where do the parasympathetic fibres of the facial nerve originate?

Answer 36

Superior salivatory nucleus in pons

Question 37

Where does the facial nerve leave the brainstem?

Answer 37

Pontocerebellar angle

Question 38

What nerve contains sensory and parasympathetic fibres of the facial nerve?

Answer 38

Nervus Intermedius

Question 39

What does the facial nerve give off at its genu?

Answer 39

Greater petrosal nerve

Question 40

What does the greater petrosal nerve join with to make the nerve of the pterygoid canal?

Answer 40

Deep petrosal nerve (joins in foramen lacerum)

Question 41

Where do the nerve of the pterygoid canal parasympathetic fibres synapse?

Answer 41

Pterygopalatine ganglion

Question 42

What nerves do the post-ganglionic parasympathetics of the facial nerve join?

Answer 42

The zygomtic branch of the maxillary and the lacrimal branch of the opthalmic

Question 43

What ganglion is irrated in hay fever?

Answer 43

Pterygopalatine ganglion

Question 44

What nerve carries the parasympathetic, secretomotor supply to the submandibular and sublingual glands?

Answer 44

Lingual nerve (branch of mandibular) carries the parasympathetic facial nerve fibres. Submandibular ganglion hangs from it

Question 45

What gland(s) does the facial nerve supply?

Answer 45

Submandibular and sublingual

Question 46

What is the glossopharyngeal parasympathetic nucleus called?

Answer 46

Inferior salvitory nucleus

Question 47

Where is the inferior salvitory nucleus located?

Answer 47

Medulla

Question 48

What does the glossopharyngeal nerve exit the cranial cavity via?

Answer 48

Jugular foramen

Question 49

Where does the glossopharyngeal nerve give off its tympanic branch?

Answer 49

Inferior to the jugular foramen

Question 50

What does the tympanic branch enter the middle ear cavity through?

Answer 50

Inferior tympanic caniliculus - forms tympanic plexus in tympanic cavity

Question 51

What is the lesser petrosal nerve a branch of?

Answer 51

Tympanic plexus

Question 52

What does the lesser petrosal nerve synapse with?

Answer 52

Post-ganglionic fibres at otic ganglion which make parotid branches of auriculotemporal nerve (CN V3)

Question 53

What is the parasympathetic nucleus of the vagus?

Answer 53

Dorsal nucleus of vagus (not shared with any other cranial nerve) located in medulla