Session 5 : Head & Neck

Question 1

What are the four nerves which the parasympathetic hitchhike on? (Preganglionic)

Answer 1

Occulomotor
Facial
Glossopharyngeal
Vagus

Question 2

Where does the sympathetic n/s arise from in the head and neck ?

Answer 2

Arises from the thoracolumbar region ( mainly T1/2)
Ganglion in paravertebral chanting is the superior cervical ganglion.
It will then ascend with the arteries, in the neck it will ascend with the carotid artery , the internal and external carotid artery.
It will ascend with these in the Neck to the head.

Question 3

What is the post ganglionic nerve which the parasympathetic will hitchhike onto ?

Answer 3

Trigeminal nerve

Question 4

Does the sympathetic n/s ever travel with cranial nerves?

Answer 4

From the internal carotid artery the ophthalmic artery will be the artery which the nerves ascend with up to a certain point.
The occulomotor nerve - retract the eyelids
The Trigeminal nerve - pupillary dilation

Question 5

Where and why is the sympathetic n/s likely to be damaged by problems in the thorax and neck?

Answer 5

The nerves wrap around the carotid artery and forms a carotid plexus here , any problems in the arterys (aneurysm, thrombus, arteriotopy) will effect the carotid plexus
Pancose tumours of the lung ( in the apical region) can also effect the nerves.

Question 6

What is horners syndrome ?

Answer 6

Series of symptoms which arise from damage to the sympathetic n/s.
miosis - pupillary constriction due to loss of innervation to the dilator muscles.
Partial ptosis - due to the lack of innervation to the tarsal muscle , bit only partial as there is still innervation to the levator superior palpebrae (via cranial nerve 3)
Anyhydrosis

Question 7

Where are the ganglia in the parasympathetic n/s in the head and neck ?

Answer 7

There are 4 ganglia :
Occulomotor nerve -Ciliary
Facial nerve - pterygopalatine & submandibular
Glossopharyngeal - otic

(Note the vagus will descend into neck and thorax and has ganglia in different areas.)

Question 8

What does the sympathetic n/s innervate and do in the head and neck ?

Answer 8

In the eye :
Dilator pupillae muscle (dilate pupil)
Tarsal muscle (retract the eyelid)

Salivary and lacrimal Glands (decreases the secretion from these )

Sweat glands (increases the amount of sweat)

Arrector pilli muscles - hair will stand on end.

Question 9

What is the parasympathetic effect in the head and neck?

Answer 9

In the eye:
Sphincter pupillae - (pupillary constriction)
Effect the cillary lens and will make it thicker this will make it easier to focus an image on the retina.

Lacrimal , nasal, subamdibular, parotid , sublingual glands - (increases in the production of fluids )

Question 10

What are the differences between an occulomotor nerve lesion and something that effects the sympathetic nervous system ?

Answer 10

With occulomotor there is full ptosis due to the loss of the main muscle which keeps the eye open , the levator superior palpebrae. (Voluntary somatic control)
In horners syndrome loss of tarsal muscle only leads to partial ptosis as it is not the most important muscle in keeping eye open .

Question 11

Where do the parasympathetic nerve arise form?

Answer 11

Nerve arises from nuclei in the brain : 
3 -> edinger westpall 
7 -> superior salivatory 
9 -> inferior salivatory 
10 -> dorsal motor

Question 12

What is the trajectory of the parasympathetic branches of the facial nerve?

Answer 12

After exiting from the internal acoustic meatus the nerve will branch into the greater petrosal and the chorda tympanic branch .
Greater Petrosal nerve - this branch of the nerve will pass over the foramen lacerum , travel in the pterygoid canal to enter into the pterygopalatine fossa via the pterygopalatine fissure. Here it will form the pterygopalatine ganglion
Chorda tympanic - this branch will travel out through the pterytympanic fissure into the infratemporal fossa, to reach the submandibular ganglion.

Question 13

Which glands does the greater petrosal branch of the facial nerve innervate?

Answer 13

Lacrimal glands
Nasal glands
Oral mucosal

Question 14

What does the Chorda tympanic branch of the facial nerve innervate ?

Answer 14

Submandibular

Sublingual

Question 15

What problems can arise if there is a lesion after the genicualte ganglion ?

Answer 15

This will effect all glands apart from the lacrimal glands, which are innervated by the greater petrosal nerve.

Question 16

What is the trajectory of the parasympathetic in the glossopharyngeal nerve branch ?

Answer 16

The nerve will hitchhike on to the tympanic branch of the nerve initially but will then jump to the lesser petrosal nerve to then leave via the foramen ovale to then enter into the infratemporal fossa to then reach the otic ganglion

Question 17

What are the main parasympathetic functions of the vagus nerve in the head and neck ?

Answer 17

Glands in the layngopharynx , larynx , Oesphagus and trachea

It has other effects in the thorax and the abdomen.

Question 18

What are the differing effects of the p/s and the s to the salivary glands ?

Answer 18

Parasympathetic - increases the secretion. But the secretions are more watery

Sympathetic - decreases the secretion , but the secretions are also more thick and viscous.

Question 19

What is a nucleus ? In terms of nervous system

Answer 19

Collection of nerve cell bodies in the brain stem or in the central nervous system

Question 20

What is a ganglion ?

Answer 20

A collection of cell bodies in other regions of the body outside of the CNS.