Parasympathetic Autonomic System (M2)

Question 1

Where does the parasympathetic system exit the CNS?

Answer 1

1. CN III
2. CN VII
3. CN IX
4. CN X
5. S2 - S4

Question 2

What are the fiber types of CN III? 1. What do these fibers innervate? 2

Answer 2

1. General somatic efferent and general visceral efferent
2. GSE: to LPS, SR, IS, MR, IO
   GVE: to iris sphincter and ciliary body

Question 3

Where is the CN III parasympathetic preganglionic cell body located? 1. Postganglionic fiber cell body location? 2

Answer 3

1. Edinger Westphal

2. Ciliary ganglion

Question 4

Describe the pathway of the CN III parasympathetic preganglionic fiber.

Answer 4

Edinger Westphal -> III -> IIIi -> branch -> inferior oblique -> motor root -> ciliary ganglion

Question 5

Describe the pathway of the CN III parasympathetic postganglionic fiber.

Answer 5

Ciliary ganglion -> short ciliary nerves -> iris sphincter and ciliary muscle

Question 6

What branch of nerves provides sensory and sympathetic innervation to the front of the eye?

Answer 6

long ciliary

Question 7

What branch of nerves provides sensory and sympathetic innervation to the back of the eye along with parasympathetic innervation to the front of the eye?

Answer 7

short ciliary

Question 8

What is the most dorsal nucleus of the oculomotor complex?

Answer 8

Edinger Westphal

Question 9

What is the oculomotor complex at the same level of in the brain?

Answer 9

superior colliculus

Question 10

Does the Edinger Westphal provide contralateral or ipsilateral innervation?

Answer 10

ipsilateral

Question 11

What is the sulcus on the ventral surface of the pons called?

Answer 11

basilar sulcus

Question 12

Where does the oculomotor nerve exit the brainstem?

Answer 12

interpeduncular fossa

Question 13

What vessel of the circle of Willis does the CN III run next to?

Answer 13

posterior communicating artery

Question 14

What section of CN III is just lateral to the posterior communicating artery?

Answer 14

basilar portion

Question 15

What section of CN III is just lateral to the basilar artery?

Answer 15

root of CN III

Question 16

What are the names of the sections of CN III from the nucleus to the cavernous portion?

Answer 16

1. nuclear
2. dorsal fasicular (Benedict’s)
3. ventral fasicular (Weber’s)
4. root
5. basilar

Question 17

What percentage of intracranial saccular aneurysms affect CN III?

Answer 17

30-35%

Question 18

When is damage to CN III a medical emergency: preganglionic, postganglionic, or both?

Answer 18

preganglionic

Question 19

Where do parasympathetic fibers run along CN III when they exit the brainstem?

Answer 19

outside (like insulation of wire)

Question 20

What does compression of CN III when it exits the brainstem first cause?

Answer 20

loss of parasympathetic

Question 21

What is a CN III palsy with EOM along with sphincter and ciliary body affected called?

Answer 21

complete ophthalmoplegia

Question 22

What fibers are affected if there is a CN III palsy without pupillary involvement? 1. What is the most likely cause of this? 2. Is this an emergency? 3. What is this called? 4

Answer 22

1. GSE (EOM’s)
2. hypertension, diabetes, other ischemic issues
3. No, refer to PCP
4. External ophthalmoplegia

Question 23

What is a compression of CN III which only affects the sphincter and the ciliary body called?

Answer 23

internal ophthalmoplegia

Question 24

What is the first sign of compression of CN III at the root section?

Answer 24

anisocoria

Question 25

Does CN III firing decrease or increase the ciliary body width?

Answer 25

decrease

Question 26

What do the parasympathetic nuclei of CN VII innervate?

Answer 26

1. one nucleus to submandibular and sublingual glands | 2. one nucleus to lacrimal gland

Question 27

Where does CN VII exit the brainstem?

Answer 27

pontomedullar junction

Question 28

What are the names of the branches that CN VII exits the brainstem as?

Answer 28

1. motor root | 2. nervus intermedius

Question 29

What type of fibers does the motor root of the facial nerve have? 1. What do these fibers innervate? 2

Answer 29

1. somatic visceral efferent | 2. muscles of facial expression, stapedius, and posterior digastric

Question 30

What type of fibers does the nervus intermedius root of the facial nerve have? 1. What do these fibers innervate? 2

Answer 30

1. general visceral efferent, general somatic efferent, and special visceral afferent 2. GVE: to lacrimal and submandibular/sublingual GSA: to ear canal SVA: to taste buds of body of tongue

Question 31

For the parasympathetic CN VII preganglionic fibers to the submandibular ganglion describe the pathway.

Answer 31

Superior salivatory nucleus -> nervus intermedius (through geniculate ganglion) -> leaves VII as chorda tympani -> through middle ear and to area below tongue to submandibular ganglion

Question 32

For the parasympathetic CN VII preganglionic fibers to the pterygopalatine ganglion (eventually to lacrimal) describe the pathway.

Answer 32

lacrimal nucleus -> nervus intermedius -> Greater superficial petrosal -> vidian (aka Nerve of Pterygoid canal) -> Pterygopalatine ganglion

Question 33

For the parasympathetic CN VII postganglionic fibers to the lacrimal gland describe the pathway.

Answer 33

pterygopalatine ganglion -> join maxillary -> infraorbital -> zygomatic -> lacrimal

Question 34

What fiber types does the glossopharyngeal nerve have? 1. What do each of these innervate? 2

Answer 34

1. SVE, GVE, SVA, GSA, GVA 2. SVE: to stylopharyngeus GVE: to parotid SVA: from taste of root of tongue GSA: from ear canal and pharynx GVA: from carotid sinus and body

Question 35

In the brain what is the order from most medial to most lateral of efferent fiber types?

Answer 35

1. GSE 2. GVE 3. SVE

Question 36

Where does CN IX exit the brainstem?

Answer 36

posterolateral fissure of medulla

Question 37

What nuclei of CN IX and CN X are found in the superior ganglion? 1. In inferior ganglion? 2

Answer 37

1. GSA nucleus | 2. GVA and SVA nuclei

Question 38

What is the nucleus of the GVE of CN IX called?

Answer 38

Inferior salivatory nucleus

Question 39

What is the nucleus of the SVE of CN IX, X, and XI called?

Answer 39

Nucleus ambiguus

Question 40

Describe the pathway of the parasympathetic preganglionic fibers of CN IX that eventually go to the parotid gland.

Answer 40

Inferior salivatory nucleus -> pass through jugular foramen -> follow tympanic branch through floor of ear to enter middle ear -> forms promontory plexus on medial wall -> lesser superficial petrosal off plexus pass through anterior wall of ear to middle cranial fossa -> through foramen ovale to enter infratemporal fossa and synapse with otic ganglion

Question 41

Describe the pathway of the parasympathetic postganglionic fibers of CN IX that eventually go to the parotid gland.

Answer 41

otic ganglion -> jumps on auriculotemporal of V3 -> follows to parotid gland

Question 42

What fiber types does the vagus nerve have? 1. What do each of these innervate? 2

Answer 42

1. SVE, GVE, SVA, GSA, GVA 2. SVE: to pharyngeal constrictors and soft palate GVE: to heart and GI system above splenic flexure SVA: from taste of pharynx GSA: from ear canal GVA: from GI system and BP in aorta

Question 43

What is the nucleus for GVE fibers of CN X? 1. Where do these fibers go to? 2

Answer 43

1. dorsal nucleus of vagus | 2. GI system and heart

Question 44

Because some fibers of parasympathetic system of CN X preganglionic from the dorsal nucleus migrate to the nucleus ambiguus, what is the result of destruction of the ambiguus?

Answer 44

flaccid paralysis of pharyngeal constrictors and have tachycardia

Question 45

Where does CN X exit the brainstem?

Answer 45

posterolateral fissure of medulla

Question 46

Where is the location of preganglionic parasympathetic cell bodies for CN X to the heart?

Answer 46

nucleus ambiguus

Question 47

Where are the postganglionic cell bodies for the parasympathetic CN X?

Answer 47

walls of organs (Meissner and Auerbachs, etc)

Question 48

Where and the cell bodies of the sacral parasympathetic fibers?

Answer 48

lateral horn of S2. S3, and S4

Question 49

What does the sacral parasympathetics innervate?

Answer 49

1. large intestine after splenic flexure 2. smooth muscle of bladder 3. smooth muscle in corpora cavernosum and spongiosum (penis)

Question 50

What does damage to the cauda equina cause?

Answer 50

1. flaccid paralysis of legs | 2. loss of defecation, micturition ability (no GVA/GVE loop) so catherterize

Question 51

Where are the cell bodies for the lumbar plexus? 1. What muscles do these innervate? 2

Answer 51

1. L1-L4 | 2. anteromedial muscles

Question 52

Where are the cell bodies for the sacral plexus? 1. What muscles do these innervate? 2

Answer 52

1. L4-S2 | 2. posterolateral muscles

Question 53

What does damage just above S2 cause?

Answer 53

1. spastic paralysis of legs | 2. rectum and bladder still works but cannot control or be aware of sensation of defication