ANS

Question 1

What does the ANS control

Answer 1

Controls function of structures with smooth muscle, cardiac muscle, and certain glands

Question 2

The ANS usually operates without conscious control EXEPT for when it uses

Answer 2

Emotion and memory

Question 3

Where do sympathetic fibers originate

Answer 3

Lateral horn of T1-L3 “thoracolumbar division”

Question 4

Where do parasympathetic fibers originate?

Answer 4

CN 3, 7, 9, 10 from the brainstem
S2-S4
“Craniosacral division”

Question 5

The major brain structure receiving afferent information for the somatic ns is the ____________ and for the autonomic ns is the __________________

Answer 5

Thalamus

Hypothalamus

Question 6

The major source of descending pathways for the somatic ns is __________and for the autonomic ns is ______________

Answer 6

Cerebral cortex

Hypothalamus

Question 7

Efferent links between the CNS and viscera innervated by ANS involve how many neurons

Answer 7

2

Question 8

What type of synapses are used for the ANS? What does this allow

Answer 8

Electrical synapse (gap junctions)
Allows for steady and widespread contractions of visceral tissue (continuous and automatic)

Question 9

Describe the myelination of the pre- and post- ganglionic ANS fibers

Answer 9

Pregang. Are lightly myelinated

Postgang. Are not myelinated

Question 10

Describe the position of sympathetic and parasympathetic postganglionic cell bodies (in ganglia)

Answer 10

Sympathetic- cell bodies typically positioned close to spinal cord

Parasympathetic- cell bodies positioned close to effector

Question 11

Describe sympathetic and parasympathetic pre/postganglionic fiber lengths

Answer 11

SYMPATHETIC short preganglionic long postganglionic

PARASYMPATHETIC long preganglionic short postganglionic

Question 12

Describe the neurotransmitters released by sympathetic and parasympathetic nervous systems

Answer 12

SMPATHETIC ACh released at terminals of preganglionic fibers and NE released at terminals of postganglionic fibers

PARASYMPATHETIC ACh released at terminals of pre and postganglionic fibers

Question 13

What receptors are found in the sympathetic and parasympathetic fibers

Answer 13

Ionotropic and metabotropic fibers

Question 14

Function of the sympathetic nervous system

Answer 14

Increase activity during times of physical and emotional stress (exercise, emergency, excitement, and embarrassment)

Question 15

Sympathetic NS triggers what reactions

Answer 15

• Pupil dilation and eyelid retraction
• Inhibition of salivation and lacrimation
• Stimulation of sweat glands
• Vasoconstriction of blood vessels to skin and gut
• Reroutes blood to muscles
• Piloerection
• Bronchodilation
• Increase in HR and cardiac output
• Reduction in neural output to digestive tract
• Inhibits digestion, inhibitions insulin release, inhibits intestinal motility and secretion
• Stimulation of hormone release
• From adrenal medulla: epinephrine and
norepinephrine
• From pancreas: glucagon

Question 16

Preganglionic neurons extend from T1-L2/3 in the lateral horn of spinal gray matter to __________ and ____________

Answer 16

Head and thorax (via upper &mid thoracic fibers)

Abdominal organs, pelvic organs, and LE targets (via lower thoracic and upper lumbar fibers)

Question 17

What different routes are take after sympathetic fibers exit SC via ventral rami

Answer 17

1. To sympathetic trunk and synapse immediately w/ post gang. Neurons at same sc level
2. Travel to sympathetic trunk and either ascend or descend to synapse in more cranial or caudal ganglia
3. Go through trunk without synapse, to synapse later with postganglionic neurons in prevertebral ganglia

Question 18

Preganglionic sympathetic diverge to synapse with multiple postganglionic fibers… this results in…

Answer 18

A single preganglionic fiber to have multiple target tissues (SNS can mass activate targets in response to stress)

Question 19

Where are the targets for the postganglionic neurons of the SNS

Answer 19

To blood vessels and skin via gray communicating rami
To viscera via prevertebral ganglia
To lower extremities (sweat, vasoconstriction, and piloerection)

Question 20

The main function of the parasympathetic NS is to

Answer 20

Increases activity during “rest and digest” periods to conserve energy use and build energy stores

Question 21

The parasympathetic NS causes

Answer 21

Pupillary constriction
Activation of salivary an lacrimal glands
Slowing of HR
Bronchoconstriction
Vasodilation of vessels to intestines, rectum, bladder, and reproductive organs

Question 22

Parasympathetic preganglionic neurons are found where? Where do they travel?

Answer 22

In the brainstem and sacral spinal cord and travel to the parasympathetic ganglia located close to the target muscles and glands

Question 23

Parasympathetic Brainstem preganglionic nu

Answer 23

Edinger-westphal nu (3)
Superior and inferior salivary nu (7)
Nu. Ambiguous (9)
Dorsal motor nu of vagus n. (10)

Question 24

Where are the sacral preganglionic nu

Answer 24

Lateral horns of S2-S4

Question 25

Preganglionic Edinger-Westphal nu project to postganglionic neurons where?

Answer 25

Ciliary muscles for pupillary constriction

Question 26

Preganglionic neurons from the superior and inferior salivary nuclei project where?

Answer 26

Salivary and lacrimal glands

Question 27

Preganglionic neurons from nu ambiguous project to postganglionic neurons where?

Answer 27

Cardiac muscles for slowing HR

Question 28

Preganglionic neurons from the dorsal motor nu of the vagus nerve project to postganglionic neurons where?

Answer 28

Thorax and abdomen for glandular secretion Cardiac muscle for slowing HR Lungs for bronchoconstriction Gut for increased motility and digestion

Question 29

Sacral preganglionic nuclei project from the lateral horns of S2-S4 to postganglionic neurons where?

Answer 29

Colon for vasodilation Rectum for vasodilation Bladder for muscle contraction Reproductive organs for vasodilation

Question 30

Most structures are innervated by sympathetic and parasympathetic ns except for These are innervated by (sympathetic/parasympathetic) only.

Answer 30

Sweat glands Erector pili muscles Most blood vessels Adrenal medulla Sympathetic innervation only

Question 31

What structure regulates the amount of parasympathetic/sympathetic input on a target organ

Answer 31

Hypothalamus

Question 32

Why do sympathetic responses are longer lasting than parasympathetic responses

Answer 32

Divergence of preganglionic neurons Longer unmyelinated postganglionic neurons Slower inactivation of NE in the synapse Presence of NE and E from adrenal medulla in blood

Question 33

Acccelerated parasympathetic responses can be activated during _____________

Answer 33

Paradoxical fear

Question 34

Define paradoxical fear

Answer 34

Fear without a way to “win” | Accepting the outcome

Question 35

List the structures that control ANS function

Answer 35

``` Hypothalamus Brainstem nu Amygdala (and other limbic structures) Medial prefrontal cortex Insular cortex ```

Question 36

ANS control is regulated by

Answer 36

Barorectptors Chemoreceptors Osmoreceptors Thermoreceptors

Question 37

Afferent input from sympathetic and parasympathetic structures serves what functions:

Answer 37

Feedback input via solitary nu for local autonomic reflex (modulates visceral motor activity) Inform higher integrative centers for more complex patterns of stimulation that may signal danger and/or may require more multi system control

Question 38

The medullary reticular formation performs ________ control on SNS and PSNS preganglionic neurons

Answer 38

Modulatory

Question 39

The dorsal horn and intermediate zone of spinal gray matter perform project neurons (bilaterally, ipsilaterally, or contralaterally) to the solitary nu

Answer 39

Ipsilaterally

Question 40

Solitary nu project where to eventually impact SNS and PSNS preganglionic neurons

Answer 40

To parabrachial nucleus Medullary reticular formation And directly to SNS/PSNS preganglionic neurons (reflex)

Question 41

How does information get to the hypothalamus to control SNS/PSNS preganglionic neurons?

Answer 41

Baro/chemo/thermo/osmo- receptors > dorsal root ganglion > dorsal horn and intermediate zone of grey matter > solitary nu > parabrachial nu ( to hypothalamus) and > thalamus >cortex > amygdala > hypothalamus > preganglionic neurons

Question 42

Explain referred pain

Answer 42

Some of the 2nd order neurons in the dorsal horn that receive visceral sensory input are part of the anterolateral system > since these neurons are also in charge of relaying input about superficial pain, visceral pain often gets perceived as cutaneous pain >travels to VPL of thalamus then to insular cortex for integration

Question 43

Where is visceral input integrated with input from other sensory modalities and from higher cognitive centers (central autonomic network)

Answer 43

Insular cortex Medial prefrontal cortex Hypothalamus Hippocampal formation and amygdala

Question 44

What is considered the primary visceral motor area

Answer 44

Insular cortex

Question 45

What is considered the primary visceral motor area

Answer 45

Medial prefrontal cortex

Question 46

What part of the central autonomic network compares input to biological set points (controls blood flow, regulates metabolism, regulates reproductive activity, and coordinates responses to threatening conditions)

Answer 46

Hypothalamus

Question 47

What nervous system is the largest and most complex system of the ANS

Answer 47

Enteric system

Question 48

The enteric system exerts control of gastrointestinal system through neuronal system embedded in the lining of GI organs to do what functions?

Answer 48

Peristalsis Segmentation Hormone secretion (gastrin and secretin)

Question 49

The enteric ns utilizes more than 30 neurotransmitters (nicknamed second brain), how much of the body’s serotonin is found in the gut? How about dopamine?

Answer 49

90% of the body’s serotonin | 50% of the body’s dopamine

Question 50

The gut is modulated by sympathetic and parasympathetic ns but also has _________________________________ that operate independently of SNS and PSNS control

Answer 50

An extensive system of nerve cells in its wall