Introduction to the Visceral Nervous System

Question 1

what is the ANS?

Answer 1

-motor portion of the visceral nervous system (=efferent)
-innervates smooth mm, cardiac mm and glands

2 major subdivisions: sympathetic and parasympathetic

Question 2

describe the general organization of the ANS

Answer 2

-somatic nervous system: includes only 1 cell body (ventral horn)

-ANS includes two cell bodies:
-preganglionic –> CNS
-postganglionic –> PNS

Question 3

what are the 3 distinct pathways of the SNS?

Answer 3

1) to the body wall (includes limbs and parts of head/neck)
2) to the body cavity cranial to the abdominal diaphragm
3) to the body cavity caudal to the abdominal diaphragm

Question 4

what are the 3 visceral structures present in the body wall?

Answer 4

1) sweat and sebaceous glands
2) arrector pili muscles
3) vasculature

Question 5

where can preganglionic cell bodes be found?

Answer 5

T1-L4 spinal cord levels only

Question 6

describe the preganglionic sympathetic pathway

Answer 6

1) lateral horn through ventral horn
2) ventral root
3) mixed spinal nerve
4) ventral ramus
5) white ramus communicans
6) paravertebral ganglion –> contains postganglionic sympathetic cell bodies

Question 7

where can postganglionic cell bodies be found?

Answer 7

in the paravertebral ganglia on every vertebral level

Question 8

what is the sympathetic chain?

Answer 8

the line-up of all the paravertebral ganglia

Question 9

what can be found attached to every level of every paravertebral column?

Answer 9

1) somatic motor cell bodies in the ventral horn
2) visceral and somatic sensory cell bodies in the DRG
3) postganglionic sympathetic cell bodies in the paravertebral ganglion
4) a gray ramus communicans
5) a connection to the paravertebral ganglion above and below

Question 10

what can be found in the T1-L4 spinal cord levels?

Answer 10

same as attached to every level with the addition of:

preganglionic sympathetic cell bodies in the lateral horn
a white ramus communicans

Question 11

what are attached to all paravertebral ganglia from the cranial cervical ganglion to ~T5?

Answer 11

cardiopulmonary spanchnic nerves (C1-T5)

Question 12

what are attached to all paravertebral ganglia from ~T5-L6?

Answer 12

abdominopelvic spanchnic nerves

Question 13

what structures are missing caudal to ~L4?

Answer 13

-no lateral horn – no preganglionic sympathetic cell bodies
-no white ramus communicantes
-everything else is there

Question 14

what axons are found in each portion of the spinal nerve complex?

Answer 14

1) somatic motor
2) somatic sensory
3) post-ganglionic

Question 15

how does the preganglionic parasympathetic axon travel to the body?

Answer 15

vagus nerve (CN X)

Question 16

where do CN X and the sympathetic chain separate?

Answer 16

middle cervical ganglion (C5-C6 paravertebral ganglia)

Question 17

what is visceral pain?

Answer 17

pain includes the damage of visceral structure, which follows the sympathetic pathway from the structure to the spinal nerve and then to the dorsal root ganglion

poorly localized

one cell body, found in the DRG

Question 18

what is nonpain?

Answer 18

includes sensations such as fullness, bloating and cramping and this follows the parasympathetic pathway to the brain

Question 19

what is visceral sensory/referred pain?

Answer 19

organs in the body cavity are associated with the same spinal cord levels that body wall structures are associated with –> pain signals get messed with/mixed up