Autonomic Nervous System

Question 1

What is the autonomic nervous system?

Answer 1

Part of the PNS that controls smooth muscle and glands

Question 2

What is the sympathetic outflow from the CNS?

Answer 2

Thoracolumbar - T1-L2 segments

Question 3

Where are the cell bodies of preganglionic sympathetic nerves?

Answer 3

Within lateral horn of grey matter of spinal cord

Question 4

What is the parasympathetic outflow from the CNS?

Answer 4

Craniosacral - cranial (4 CNs) or sacral (S2-S4) - pelvic splanchnics

Question 5

Which muscles do sympathetic nerves contract?

Answer 5

Smooth muscle of blood vessels, eyelid (tarsal muscle) and iris (dilator pupillae)

Question 6

Which muscles do parasympathetic nerves contract?

Answer 6

Smooth muscle of iris (sphincter pupillae) and ciliary body

SM of respiratory and gastrointestinal tract

Question 7

Which muscle in the eyelid is controlled by sympathetics?

Answer 7

Superior tarsal muscle

Question 8

Which muscle in the iris is controlled by sympathetics?

Answer 8

Dilator pupillae

Question 9

What is lost in partial ptosis?

Answer 9

Only lost action of sympathetics - still got oculomotor nerve

Question 10

What happens to the eye if sympathetic innervation is lost?

Answer 10

Partial ptosis (superior tarsal muscle lost)
Constricted pupil (dilator pupillae lost)

Question 11

Pathology involving the apex of the lung and internal carotid artery can cause what syndrome?

Answer 11

Horner’s syndrome

Question 12

Which cranial nerves carry parasympathetic fibres from the brainstem?

Answer 12

Oculomotor
Facial
Glossopharyngeal
Vagus

Question 13

What do sympathetic nerves to the head and neck hitch hike on to?

Answer 13

Blood vessels

Question 14

Post ganglionic parasympathetics hitch hike onto branches of what nerve?

Answer 14

CN V (trigeminal)

Question 15

What is the Edinger Westphal nucleus?

Answer 15

The parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.

Question 16

Why do you get constriction of both pupils even if you shine a light in just one eye?

Answer 16

Optic nerve sense light, sends signal to brain
COmmunication from optic nerve into midbrain
Communicates with EW on same side as well as the EW nucleus on opposite side

Question 17

What are the target tissues of parasympathetics in the head and neck?

Answer 17

Smooth muscle in iris (constrictor) 
Ciliary muscle (controls lens)
Lacrimal gland
Salivary glands
Mucosal glands in nasal/oral mucos/resp tract

Question 18

Which ganglion do parasympathetic fibres of the oculomotor nerve pass through?

Answer 18

Ciliary ganglion

Question 19

On which part of the nerve do parasympathetic fibres run?

Answer 19

On the outside

Question 20

From what nucleus do parasympathetic fibres of the oculomotor nerve emerge?

Answer 20

Edinger Wesphal nucleus

Question 21

What are the four parasympathetic nuclei?

Answer 21

Edinger Westphal
Superior salivary
Inferior salivary
Dorsal motor

Question 22

What are the four ganglia associated with parasympathetics in the head and neck?

Answer 22

Ciliary
Submandibular
Pterygopalatine
Otic

Question 23

After the ciliary ganglion, what do the postganglionic parasympathetic fibres of CN III hitch hike onto?

Answer 23

Branches of the trigeminal nerve (as do all postganglionic PS fibres)

Question 24

What do parasympathetics of the oculomotor nerve do to the iris?

Answer 24

Constricts it

Question 25

What is the consensual light reflex?

Answer 25

Response on one side of the body when the other side has been stimulated

Question 26

Why does the consensual light reflex happen?

Answer 26

Because the afferent signal sent through one optic nerve connects to the Edinger-Westphal nucleus, whose axons run to both the right and the left oculomotor nerves.

Question 27

What do parasympathetics of the oculomotor nerve do to the lens?

Answer 27

Fatten it - contract ciliary muscle

Question 28

After passing through the internal auditory meatus, where do parasympathetics of the facial nerve enter?

Answer 28

Petrous bone, where it gives off a few branches

Question 29

What are the two main branches of parasympathetics given off by the facial nerve in the petrous bone?

Answer 29

Greater petrosal nerve and chorda tympani

Question 30

At which point does the greater petrosal nerve branch off?

Answer 30

At the point of geniculate ganglion

Question 31

What is the target tissue of the greater petrosal nerve?

Answer 31

Lacrimal gland, palatine and nasal glands

Question 32

Where is the pterygopalatine ganglion?

Answer 32

In the pterygopalatine fossa

Question 33

What is the ganglion associated with the greater petrosal nerve?

Answer 33

Pterygopalatine ganglion

Question 34

After passing through the pterygopalatine ganglion, what do postganglionic fibres of the facial nerve jump onto?

Answer 34

Branches of the trigeminal nerve

Question 35

What ganglion is associated with the chorda tympani nerve?

Answer 35

Submandibular ganglion

Question 36

How do parasympathetics get to the salivary glands (submandibular and sublingual)?

Answer 36

Join the chorda tympani nerve to the submandibular ganglion and then join branches of the trigeminal nerve

Question 37

What can facial nerve lesions cause?

Answer 37

Dry eye Dry mouth Loss of taste Loss of muscles of facial expression

Question 38

What branch of the glossopharyngeal nerve gives sensory to the middle ear?

Answer 38

Tympanic nerve

Question 39

What is the target tissue of parasympathetics of the glossopharyngeal nerve?

Answer 39

Parotid gland

Question 40

How do parasympathetics of the glossopharyngeal nerve reach the parotid gland?

Answer 40

Runs with tympanic nerve through petrous bone in middle ear, exits via lesser petrosal nerve, goes to otic ganglion, postganlionic fibres hitch hike onto CN V to reach parotid gland

Question 41

What is the vagus nerve in as it runs down the length of the neck?

Answer 41

Carotid sheath