C14 4-8

Question 1

Sympathetic vs. Parasympathetic: CNS origin

Answer 1

Sym: Thoracolumbar, Lateral horns of T1-L2

Para: Craniosacral (brain stem nuclei of cranial nerves III, VII, IX, X and sacral region of spinal cord, segments S2-S4.)

Question 2

Sympathetic: Location of Ganglia

Answer 2

Within a few cm of CNS:

• alongside vertebral column
  (sym trunk/vertebral chain/paravertebral ganglia)
• anterior to vertebral column
  (collateral/prevertebral ganglia).
• Also, adrenal medullae

Question 3

Parasympathetic: Location of Ganglia

Answer 3

Within the visceral organ or close to the organ served Terminal/intramural ganglia.

Question 4

Sympathetic: General fiber pathways

Answer 4

Sym: Thoracocolumbar/lateral horn –> Ventral root –> Nerve –> Ventral ramus –> White ramus –> sympathetic trunk ganglion –>
4 options:
1. synapse in the same trunk ganglion, exit thru gray ramus, travel on branches of rami to effector
2. Ascend or descend to synapse with another trunk ganglion,
3. Bypass trunk ganglia, enter/form splanchnic nerve, and synapse in a distant collateral ganglion (abdomen/pelvis)
4. Bypass both trunk and collateral ganglia and synapse in the adrenal medullae.

Question 5

Parasympathetic: General fiber pathways

Answer 5

Para: Craniosacral –> Terminal ganglia –> Effector cell

Question 6

Sympathetic vs. Parasympathetic: Length of fibers

Answer 6

Sym: Short preganglionic –> long postganglionic Para: long –> short

Question 7

Sympathetic vs. Parasympathetic: preganglionic axons branches

Answer 7

Sym: more than 20 Para: less than four (i.e. talks to how may postganglionic?)

Question 8

Sympathetic vs. Parasympathetic: Degree of response

Answer 8

Sym: short preganglionic fibers with extensive branching facilitate the activation of many structures simultaneously (mass activation).

Para: long preganglionic fibers with limited branches result in a local response.

Question 9

Sympathetic vs. Parasympathetic: Rami communicantes?

Answer 9

Sym: yes, grey and white Para: no

Question 10

White rami

Answer 10

Short pathway containing preganglionic sympathetic axons.

axons: pass thru anterior root –> nerve –> white Ramus –> nearest sympathetic trunk ganglion

Entry to the sympathetic trunk! Found only in T1-L2 cord segments.

Question 11

Grey rami

Answer 11

Short pathway containing postganglionic axons that connect ganglia of the sympathetic trunk to spinal nerves.

Departure point from the sympathetic trunk - allow sympathetic output to all parts of body.

Found by every trunk ganglion from cervical to sacral.

Question 12

4. Explain why parasympathetic activation is local and discrete, and sympathetic activation can result in mass activation.

Answer 12

Parasympathetic : long preganglionic fibers with limited branches result in a local response. Sympathetic: short preganglionic fibers with more extensive branching facilitates the activation of many structures simultaneously (mass activation). Also - thru medulla, release NE into blood, everywhere affected.

Question 13

6. Name the four cranial nerves associated with the parasympathetic division.

Answer 13

Oculomotor, facial, glossopharyngeal, vagus

Question 14

What is the action of the Oculomotor nerve in the parasympathetic division?

Answer 14

Control ciliary and iris/sphincter pupillae muscle.
Pupil constriction, lens shape for focusing.

Pre-gan CB -Accessory occulomotor nuclei/midbrain –> Pre-gan Axon - oculomotor nerve –>
Post-gan CB -Ciliary Ganglia, –>

Question 15

What is the action of the Facial nerve in the parasympathetic division?

Answer 15

Activate lacrimal and nasal glands, palate, (pharynx).
Pre-gan CB - Lacrimal nuclei/pons –>
Pre-gan Axon - facial nerve –>
Post-gan CB - pterygopalatine ganglia (hay fever).

Activate submandibular and sublingual glands.
Pre-gan CB - Superior salivary nuclei/pons –>
Pre-gan Axon - facial nerve –>
Post-gan CB - Submandibular ganglia.

Question 16

What is the action of the Glossopharangeal nerve in the parasympathetic division?

Answer 16

Activate the parotid salivary glands.

Pre-gan CB - Inferior salivatory nuclei/pons –>
Pre-gan Axon - glossopharangeal –>
Post-gan CB - otic ganglia

Question 17

What is the action of the Vagus nerve in the parasympathetic division?

Answer 17

90% of para, Serves heart, lungs, and abdominal viscera.

Dorsal motor nuclei/medulla –>
send branches to cardiac/pulmonary/esophageal plexuses –>
at the esophagus ant/post vagus trunks join together —>
send fibers thru abdominal aortic plexus —>
terminal/intramural ganglia

Question 18

Where are the cell bodies of parasympathetic postganglionic neurons found?

Answer 18

Terminal/intramural ganglia. Near or in the organ served.

Question 19

Sacral outflow of parasympathetic?

Answer 19

S2-S4. Preganglionic axons in sacral spinal branch off to form pelvic splanchnic nerves –> synapse with terminal ganglia.

large intestine,
urinary bladder,
ureters,
repro organs.

Question 20

What does the sympathetic division innverate?

Answer 20

Visceral organs and all visceral structures in the somatic part of the body (i.e. glands/smooth muscle in the soma - sweat, arrector pili)

Question 21

Where are the lateral horns found?

Answer 21

Gray matter of spinal cord in T-L segments. No lateral horns found in the sacral region!

Question 22

Sympathetic trunk?

Answer 22

Flank each side of the vertebral column and extend from neck to pelvis.

Consist of sympathetic ganglia and fibers running from one ganglion to another.

Symp fibers only arise from T-L!!!

Question 23

Sympathetic trunk/paravertebral/chain ganglia vs. collateral/prevertebral ganglia?

Answer 23

Trunk ganglia:

• found in sympathetic trunk,
• 22-23 pairs
• connections for head, neck, thoracic cavity.
• extend from neck to pelvis

Collateral ganglia:

• Found anterior to the vertebral column, close to ab arteries.
• Not paired or segmentally arranged.
• Occur only in abdomen and pelvis - innervate organs below diaphragm.
• Five major: celiac, superior and inferior mesenteric, aorticorenal, renal.

Question 24

Where do I find the postganglionic axons of cranial nerves III, VII, IX?

Answer 24

Most hitch a ride on the trigeminal nerve.

Question 25

What ganglia are connected to cranial outflow?

Answer 25

Ciliary, pterygopalantine, submandibular, Otic (and intramural for vagus)