8 - Head & Neck - Autonomic Innervation

Question 1

Is the ANS part of the central or peripheral nervous system?

Answer 1

Peripheral nervous system

Question 2

Name the 4 parasympathetic ganglia in the head and neck:

Answer 2

1) Ciliary
2) Pterygopalatine
3) Submandibular
4) Otic

Question 3

Which cranial nerves do the parasympathetic fibres hitch-hike on, to reach their target organs?

Answer 3

Preganglionic: III, VII, IX, X
Postganglionic: V

Question 4

Where do the parasympathetic nerves to the sphincter pupillae and the ciliary body originate from?

Answer 4

Edinger-Westphal nuclei

Brainstem

Question 5

The parasympathetic nerves from the Edinger-Westphal nuclei hitch-hike on which cranial nerves? What are their target tissues?

Answer 5

Preganglionic = CN III
Postganglionic = CN V

Ciliary body
Sphincter pupillae

Question 6

What effect do the parasympathetic nerves have on the eye?

Answer 6

1) Constrict pupil

2) Accomadation reflex = allows near vision

Question 7

Where do the parasympathetic nerves to the lacrimal, nasal, submandibular and sublingual glands originate from?

Answer 7

Superior salivary nuclei

Brainstem

Question 8

The parasympathetic nerves from the Superior salivary nuclei hitch-hike on which cranial nerves?

Answer 8

Preganglionic = CN VII
Postganglionic = CN V

Question 9

Where is the parasympathetic ciliary ganglion located?

Answer 9

Bony orbit

- Between lateral rectus + optic nerve

Question 10

Where is the parasympathetic pterygopalatine ganglion located?

Answer 10

Pterygopalatine fossa

Question 11

Where is the parasympathetic submandibular ganglion located?

Answer 11

Inferior to Lingual nerve

Question 12

Where is the parasympathetic otic ganglion located?

Answer 12

Inferior to foramen ovale

Question 13

What effect do the parasympathetic nerves have on the salivary and lacrimal glands?

Answer 13

Increase secretion

Question 14

Where do the parasympathetic nerves to the parotid gland originate from?

Answer 14

Inferior Salivary nuclei

Brainstem

Question 15

The parasympathetic nerves from the inferior salivary nuclei hitch-hike on which cranial nerves?

Answer 15

Preganglionic = CN IX
Postganglionic = CN V

Question 16

Where do the parasympathetic nerves to the smooth muscle and glands of the trachea, bronchi and GI tract originate from?

Answer 16

Dorsal motor nuclei

Brainstem

Question 17

The parasympathetic nerves from the dorsal motor nuclei hitch-hike on which cranial nerve?

Answer 17

CN X

Question 18

The parasympathetic nerves to the head and neck originate from which nuclei in the brainstem?

Answer 18

1) Edinger-Westphal nuclei
2) Superior salivary nuclei
3) Inferior salivary nuclei
4) Dorsal motor nuclei

Question 19

The sympathetic fibres to the head and neck originate from which vertebral level? At which ganglion of the sympathetic chain do they synapse?

Answer 19

T1
T2

Superior cervical ganglion (C1/2 level)

Question 20

What are the target tissues of the sympathetic nerves to the head and neck?

Answer 20

• Superior tarsal muscle
• Dilator pupillae
• Sweat glands
• Blood vessels
• Nasal glands
• Salivary glands

Question 21

Describe the route of the sympathetic nerves from the superficial cervical ganglion to the superior tarsal muscle:

Answer 21

• Wind around internal carotid artery into the skull (to cavernous sinus)
• Joins CN III to superior tarsal muscle

Question 22

What is the function of the sympathetic nerve which hitch-hikes on CN III?

Answer 22

Helps elevate eyelid

- Superior tarsal muscle

Question 23

Describe the route of the sympathetic nerves from the superficial cervical ganglion to the dilator pupillae muscle:

Answer 23

• Wind around internal carotids artery into the skull (to cavernous sinus)
• Joins on CN V to dilator pupillae muscle

Question 24

What is the function of the sympathetic nerve which hitch-hikes on CN V?

Answer 24

Pupillary dilation

- Dilator pupillae muscle

Question 25

Which artery do the sympathetic nerves which innervate structures in/around the eye hitch-hike on?

Answer 25

Internal carotid artery

Question 26

Which artery do the sympathetic nerves which innervate blood vessels and sweat glands in the face hitch-hike on?

Answer 26

External carotid artery

Question 27

What is the function of the sympathetic nerves which wind around the external carotid artery?

Answer 27

- Vasoconstriction - Sweating - Decreased secretion of nasal and salivary glands

Question 28

Why may someone with a lung tumour have miosis, partial ptosis and anhydrosis?

Answer 28

Due to damaged or stretched sympathetic nerves, which arise in the chest (therefore can be damaged by a growth in the chest)

Question 29

What is the classic presentation of Horner's syndrome?

Answer 29

- Miosis - Partial ptosis - Anhydrosis

Question 30

What is miosis?

Answer 30

Loss of pupillary dilation = constricted pupil

Question 31

Why is ptosis due to Horner's syndrome only partial?

Answer 31

- Paralysis of superior tarsal muscle due to loss of sympathetic innervation - Levator palpebrae superioris is still functioning, and is able to elevate eyelid partially

Question 32

List some causes of Horner's syndrome:

Answer 32

- Pancoast (apex) lung tumour - Trauma - Carotid artery dissection - Spinal cord lesion

Question 33

What is Horner's syndrome?

Answer 33

Triad of: Partial ptosis, miosis and anhydrosis affecting 1 side of the face Due to damaged sympathetic fibres to the head and neck

Question 34

Which cranial nerves 'carry' pre-ganglionic parasympathetic fibres, and what are the ganglia associated with each nerve?

Answer 34

III - Ciliary ganglion VII - Pterygopalatine + Submandibular ganglia IX - Otic ganglion X - Many small ganglia located in target organs (not in head/neck)

Question 35

Name the nerves which branch off CN VII before it enters the parotid gland:

Answer 35

- Greater petrosal nerve - Nerve to stapedius - Posterior auricular nerve - Chorda tympani - Nerve to digastric - Nerve to stylohyoid

Question 36

Which 2 canals does the facial nerve pass through, and remain intracranial?

Answer 36

1) Internal acoustic meatus | 2) Facial canal

Question 37

Via which foramen does the Facial nerve pass through to become extracranial?`

Answer 37

Stylomastoid foramen

Question 38

Why does an extradural haemorrhage form a lens shape?

Answer 38

The dura mater is tightly adhered to the periosteum

Question 39

In which layer of the scalp do blood vessels (supplying the scalp) run in?

Answer 39

Dense connective tissue layer

Question 40

Name the ganglion which is formed by the facial nerve after the greater petrosal nerve has branched off:

Answer 40

Geniculate ganglion

Question 41

If a lesion of the facial nerve occurred at the geniculate ganglia, how would the patient present?

Answer 41

- Hyperacusis - Dry mouth - Loss of taste - Paralysed facial muscles (Greater petrosal nerve has already branched off the facial nerve before the geniculate ganglion)

Question 42

Name the arteries supplying the side of the scalp and forehead:

Answer 42

- Superficial temporal artery - Supratrochlear artery - Supraorbital artery