Autonomic Nervous System

Question 1

T/F: All postganglionic nerve fibers are unmyelinated?

Answer 1

True

Question 2

T/F: Acetylcholine is used as a neurotransmitter ONLY in the parasympathetic nervous system?

Answer 2

False. ACh is used at the first synapse of sympathtic neurons. NE is then used at the 2nd synapse of the sympathetic neurons, while ACh is used entirely throughout the parasympathetic pathway.

Question 3

In what vertebral segments can you expect to find sympathetic preganglionic fibers?

Answer 3

T1-L2/3

Question 4

Think of the effects of Sympathetics and Parasympathetics on the cardiorespiratory system. Where are the preganglionic neurons located for the following: bronchial muscles & lung, heart rate/output, arteries (muscles), arteries (skin), and arteries (viscera)? Check yourself with this table.

Answer 4

Question 5

What are the effects on the GI tract and the GU tract in response to sympathetics and parasympathetics?

(try to fill in the chart)

Answer 5

Dr. P taught that one way to remember innervation associated with erection and ejaculation.

point (erection): parasympathetic

shoot (ejaculation): sympathetic

Question 6

Now think about the head.

Answer 6

Here are the answers:

Question 7

The parasympathetic fibers that hitch a ride with CN III are going to what targets?

Answer 7

pupil sphincter

ciliary muscle

accomodation reflex

(ciliary ganglion)

Question 8

The parasympathetic fibers hitching a ride with CN VII are going to what target(s)?

Answer 8

lacrimal and nasal glands (ptergyopalatine ganglion)

submandibular and sublingual glands (submandibular ganglion)

Question 9

The parasympathetic fibers running with CN IX are going to what target(s)?

Answer 9

parotid gland (otic ganglion)

Question 10

The parasympathetics fibers traveling with CN X are going to what target(s)?

Answer 10

heart

bronchi

gastrointestinal tract

(I believe all three can be classified under dorsal motor nucleus of Vagus)

Question 11

Where would you expect to see the Edinger-Westphal nucleus? What is the signficance of this structure?

Answer 11

nucleus is located in the midbrain;

it is the location for the ciliary ganglion for pupillary constrictor muscle fibers and for the ciliary muscle (accomodation)

Question 12

Where is the superior salivatory nucleus located?

Answer 12

tegmentum of pons

Question 13

Where is the inferior salivatory nucleus located?

Answer 13

medulla

Question 14

Where is the dorsal motor nucleus of Vagus located?

Answer 14

medulla

Question 15

Other than the dorsal motor nucleus of the vagus, what other parasympathetic nucleus is associated with CN X?

Answer 15

nucleus ambiguus

(parasympathetic preganglionic fibers that serve the heart)

Question 16

T/F:

Parasympathetic, preganglionic nerve cell bodies are found exclusively within the brainstem.

Answer 16

False

nerve cell bodies associated with cranial nerves are found exclusively in the brainstem, however there are also preganglionic nerve cell bodies in the lateral horn of spinal cord between S2-4 (which goes to pelvic splanchnic nerves)

Question 17

What are the four things that preganglionic sympathetic fibers do after leaving the ventral root?

Answer 17

1. some fibers synapse in nearest ganglion
2. some fibers ascend chain, synapse in SCG or MCG
3. some descend, synapse in lumbar/sacral ganglia
4. some traverse chain, emerge as splachnic nerves

Question 18

What are the ways that sympathetic postganglionic fibers reach the head?

Answer 18

cervical ganglia & carotid plexus

Question 19

Loss of sympathetic innervation to the face is known as what syndrome?

Answer 19

Horner syndrome

Question 20

These are some symptoms of Horner Syndrome. Define them:

Ptosis

Miosis

Endopthalmos

Anhydrosis

Heterochromia

Answer 20

Ptosis: eyelid droop (superior tarsal muscle)

Miosis: small pupil

Endopthalmos: apparent sunken eye

Anhydrosis: dry skin

Heterochromia: different colored eyes (occurs if condition sets in before age 2)

Question 21

Why does referred pain occur?

Answer 21

visceral structure is innervated by same cord level as surface structure

Question 22

What does the enteric nervous system innervate?

Answer 22

intestinal tract

pancreas & gall bladder

Question 23

What is (are) the neural plexus(es) of the intestinal tract?

Answer 23

myenteric plexus (Auerbach)

submucous plexus (Meissner)

Question 24

What is the function of the enteric nervous system?

Answer 24

provides primary control of motility and secretion