Autonomic Nervous System

Question 1

What is the ANS in broad terms?

Answer 1

the efferent component of the visceral nervous system

aka the motor component of the visceral nervous system

Question 2

visceral nervous system

Answer 2

lots of internal organs and smooth muscle!

Question 3

What can the ANS be broken into?

Answer 3

parasympathetic and sympathetic nervous systems

Question 4

sympathetic nervous systems

Answer 4

part of the ANS (visceral efferent / motor)

quick actions that use energy

ex: increase HR and vasoconstriction

Question 5

parasympathetic nervous systems

Answer 5

part of the ANS (visceral efferent / motor)

preserve and store energy

ex: digestion and vasodilation

Question 6

What do autonomic impulses travel along?

Answer 6

a chain of 2 neurons

a preganglionic and postganglionic neuron

Question 7

where is a preganglionic neuron?

Answer 7

in the CNS (brain or spinal cord)

Question 8

what neurotransmitter does a preganglionic neuron relase?

Answer 8

acetylcholine

Question 9

what neurotrasmitter does postganglionic neuron release in sympathetic nervous system?

Answer 9

norepinephrine

EXCEPT when innervating sweat glands (acetylcholine)

Question 10

what neurotrasmitter does postganglionic neuron release in parasympathetic nervous system?

Answer 10

acetylcholine

Question 11

paravertebral ganglia

Answer 11

ganglia located lateral to spinal column

look like beads on a string

ONLY contain sympathetic cell bodies and fibers

Question 12

prevertebral ganglia

Answer 12

found to close to or within walls of target organs

can contain parasympathetic and sympathetic cell bodies / fibers

Question 13

how to preganglionic fibers leave the spinal cord?

Answer 13

through the vental root

Question 14

what is the ventral root?

Answer 14

the motor root

Question 15

when preganglionic (sympathetic) fibers leave the spinal cord through the ventral root, what do they enter neck?

Answer 15

the paravertebral ganglia

“beads on a string” lateral to spinal cord

Question 16

are preganglionic fibers myelinated?

Answer 16

yes! this makes them leave the ventral ramus through a white communicating ramus

Question 17

how do preganglionic fibers get to sympathetic trunk?

Answer 17

through the white communicating ramus

Question 18

sympathetic trunk

Answer 18

beads on a string chain of sympathetic paravertebral column

Question 19

are postganglionic fibers myelinated?

Answer 19

no! they leave the spinal nerve through grey ramus as a result

Question 20

what is a ganglia?

Answer 20

clusters of nerve cell bodies

Question 21

where are white rami found?

Answer 21

only T1-L2

because this is where the preganglionic fibers are and they are myelinated which makes them white

Question 22

where are grey rami found?

Answer 22

found at all vertebral levels

because postganglionic sympathetic axons can ascend and descend down the sympathetic trunk

Question 23

where are prevertebral ganglia?

Answer 23

closer to the target organ

Question 24

adrenal gland

Answer 24

can accept preganglionic sympathetic fibers directly

can synapse here and release epinephrine / norepinephrine

Question 25

preganglionic parasympathetic neurons

Answer 25

have a craniosacral distribution more limited than the sympathetic neurons

Question 26

where does most of the body wall innervation in the ANS come from?

Answer 26

sympathetic neurons parasympathetic neurons have largely craniosacral distribution

Question 27

vagus nerve

Answer 27

preganglionic parasympathetic neuron