Autonomic Nervous System

Front 1

What is the general role of the ANS?

Back 1

Maintain homeostasis

Front 2

What do cortical autonomic centers control in the ANS?

Back 2

Initiating autonomic responses to emotion and pain

Front 3

What is the role of brainstem centers in the ANS?

Back 3

Receive visceral information, generate outputs through peripheral autonomic nerves

Front 4

What are the roles of the hypothalamus in the ANS?

Back 4

Control circadian rhythm, temperature regulation, hunger/thirst, serves as a relay center for all sympathetic autonomic information descending to the body

Front 5

What are the 4 components of the ANS?

Back 5

1. Neurohumoral
2. Intrinsic enteric
3. Sympathetic
4. Parasympathetic

Front 6

What does the Nuerohumoral part of the ANS consist of and regulate?

Back 6

Consists of hormones which regulate energy metabolism (pituitary-adrenal), blood volume (angiotensin), and other functions

Front 7

What is the intrinsic enteric nervous system?

What does it regulate?

Back 7

Interconnected neurons in the wall of the bowel from the esophagus to the anus

Regulates bowel motility, secretion, etc. --> bowel independent of extrinsic input

Front 8

What are 5 characteristic sympathetic responses?

Back 8

1. Pupils dilate
2. Muscle vasculature dilates
3. Heart rate and bp increases
4. Sweating
5. Digestive system put on hold

Front 9

What are 4 situations in which the sympathetic system is activated?

Back 9

1. emotional stress
2. exercise
3. dehydration
4. disease states

Front 10

What are 4 characteristics of the parasympathetic system?

Back 10

1. Pupils constrict
2. Heart rate slows
3. Secretion and digestion are stimulated (gut and salivary glands)
4. Bladder emptying and sexual function

Front 11

Where do the preganglionic sympathetic neurons lie in the spinal cord?

Back 11

Intermediolateral cell column of thoracic and upper lumbar cord (T1-L3)

Front 12

Where do autonomic motor neurons sit in the spinal column, and how does this compare with where they exit the column?

Back 12

Sit posterior and lateral to the anterior horn cells

Exit in the anterior root along with the somatic motor fibers

Front 13

What is the pathway of sympathetic innervation to the head?

Back 13

Myelinated preganglionic sympathetic axons ascend via white ramus --> paravertebral sympathetic chain --> sympathetic chain ganglia (superior cervical ganglia) --> head

Front 14

What is Horner's syndrome?

Back 14

Damage to the ascending sympathetic chain --> small pupil, loss of sweating, ptosis on one side of face

Front 15

What do sympathetic fibers innervate in the head?

What happens in Horner's syndrome?

Back 15

Innervate superior tarsal muscle --> open eyes wide in fight or flight

In Horner's, lose the innervation --> ptosis

Front 16

What are 4 misplaced sympathetic ganglia (not in spine)?

Back 16

Celiac
Superior mesenteric
Inferior mesenteric
Adrenal medulla

Front 17

What are 3 unpaired prevertebral sympathetic ganglia? What do they do?

Back 17

Celicac
Superior mesenteric
Inferior Mesenteric

Innervate the bowel and bladder

Front 18

Adrenal chromaffin cells...
a. input?
b. output?

Back 18

a. Preganglionic sympathetic fibers
b. Epinepherine into circulation

Front 19

What are 2 similarities between autonomic and somatic motor nerves?

1 difference?

Back 19

Both are cholinergic, both send axons out via the anterior spinal roots

Autonomics synapse outside the spinal cord in the autonomic ganglia before going to targets

Front 20

What NT is used at the synapse in the sympathetic ganglia?

What type of receptor does the sympathetic ganglion neuron use

Back 20

Ach

Ach receptor, nicotinic

Front 21

What occurs to the signal between the sympathetic preganglionic nerve and the ganglionic neuron?

Back 21

Signal integration (many inputs per ganglionic neuron)

Amplification (one input goes to many ganglionic neurons)

Front 22

What types of fibers do Sympathetic ganglionic neurons send out to target organs?

Back 22

Unmyelinated postganglionic fibers to target organs

Front 23

Besides target organs, where might sympathetic postganglionic axons of the ANS go?

Back 23

May rejoin spinal roots via gray (unmyelinated) communicating ramus

Front 24

What NT fibers do sympathetic (postganglionic) fibers release at their target organs? What receptors are there?

What is one exception?

Back 24

Release of NE to adrenergic receptors

Sympathetic fibers that innervate sweat glands release Ach

Front 25

From where do preganglionic parasympathetic neurons arise?

Back 25

Brainstem or sacral spinal cord

Front 26

How do cranial parasympathetics travel?

Back 26

Via CN 3, 7, 9, and 10

Front 27

What is the function of the Vagus nerve?

Back 27

Autonomic input to most of the viscera of the body (neck to distal 1/3 colon)

Front 28

Where do sacral autonomic neurons sit in the spinal section?

What do they innervate?

Back 28

Intermediolateral cell column

Innvervate the rectum, bladder, and reproductive organs

Front 29

How does the placement of parasympathatic ganglia differ from sympathetic ganglia?

Back 29

Parasympathetic ganglia are found very close to the target organ

Front 30

How do preganglionic parasympathetic axons travel in comparison to their sympathetic counterparts?

Back 30

Travel much further before synapsing with ganglia

Front 31

What NT is used at parasympathetic ganglia?

What NT is released by postganglionic fibers and what type of receptors do target organs have?

Back 31

Ach

Ach --> Ach muscarinic receptors (target organs)

Front 32

What do all autonomic ganglia use as a NT?

Back 32

Ach

Front 33

What do postganglionic nerves release? (sympathetic/parasympathetic/exceptions)

Back 33

Parasymp. = Ach

Sympathetic = NE

Exception = sympathetic fibers innervating sweat glands, piloerector muscles, and some blood vessels release Ach

Front 34

What are 4 nuceli of the parasympathetic system?

Back 34

Edinger Westphal
Salivatory
Dorsal Nucleus of X
Nucleus ambiguus

Front 35

What does the EW nucleus send out?

Back 35

Axons w/ CN 3 --> pupil constriction, lens accomodation

Front 36

Where do axons from the salivatory nuclei go?

Back 36

Salivary glands via CN 7 and 9

Front 37

What fibers come from the dorsal nucleus of X?

What do they stimulate (3)?

Back 37

Give rise to secretomotor fibers of the Vagus

Stimulate:
1. Gastric secretion
2. Gut motility
3. Respiratory secretions

Front 38

Where do axons from the Nucleus ambiguus go?

What do they do? (2)

Back 38

Via vagus --> heart, lungs, pharynx

1. Decrease heart rate
2. Bronchial constriction

Front 39

Where do cells of the sympathetic system reside?

Back 39

Intermediolateral column of T1-L3

Front 40

What are 3 notable sympathetic ganglia?

Back 40

Superior cervical
Celiac and mesenteric
Sympathetic chain

Front 41

What does the superior cervical ganglion supply?

Functions (3)?

Back 41

Supplies sympathetics to the head

1. pupillary dilation
2. facial sweating
3. elevation of the eyelid

Front 42

What do the celiac and mesenteric ganglia supply?

Functions (2)?

Back 42

Gut

1. Vasoconstriction
2. Inhibition of secretions

Front 43

What does the sympathetic chain ganglia supply?

Functions (5)?

Back 43

Thorax and periphery

1. Increase heart rate
2. Dilate bronchi
3. Selectively vasoconstrict
4. Vasodilate in active muscles
5. Stimulate sweating

Front 44

What is the pathway for parasympathetic afferents?

Back 44

Internal organs --> vagus --> nodose ganglion --> solitary tract (medulla) --> nucleus of solitary tract

Front 45

What kind of information does the nucleus of the solitary tract receive?

Back 45

Blood pressure, CO2 levels, gut distention

Front 46

How do sympathetic afferents re-enter the spinal cord?

What is the effect of this?

Back 46

Re-enter the dorsal horn along with sensory afferents from the skin

As a result, visceral pain is often perceived as originating from body surface (referred pain)

Front 47

Heart
a. Parasympathetic
b. Sympathetic

Back 47

a. Decrease heart rate, CO decreases
b. Increase heart rate, CO increases

Front 48

Lung bronchioles
a. Parasympathetic
b. Sympathetic

Back 48

a. constrict
b. dilate

Front 49

LIver glycogen
a. Parasympathetic
b. Sympathetic

Back 49

a. No effect
b. Glycogen breakdown, blood glucose increase

Front 50

Basal metobolism
a. Parasympathetic
b. Sympathetic

Back 50

a. No effect
b. Increases 2x

Front 51

Fat tissue
a. Parasympathetic
b. Sympathetic

Back 51

a. No effect
b. Breakdown of fat, blood FAs increase

Front 52

Stomach
a. Parasympathetic
b. Sympathetic

Back 52

a. Increased secretion of HCl and digestive enzymes, increased motility
b. Decreased secretion and motility

Front 53

Intenstine
a. Parasympathetic
b. Sympathetic

Back 53

a. increased secretion and motility
b. decreased secretion and motility

Front 54

Urinary bladder
a. Parasympathetic
b. Sympathetic

Back 54

a. Relaxes sphincter, detrusor contracts, urination promoted
b. Constricts sphincter, relaxes detrusor, urination inhibited

Front 55

Rectum
a. Parasympathetic
b. Sympathetic

Back 55

a. Relaxes sphincter, contracts wall muscles, defecation promoted
b. Constricts sphincter, relaxes wall muscles, defecation inhibited

Front 56

Eye
a. Parasympathetic
b. Sympathetic

Back 56

a. Iris constricts, adjust for near vision
b. Iris dilates, adjust for far vision

Front 57

Male sex organ
a. Parasympathetic
b. Sympathetic

Back 57

a. promote erection
b. promote ejaculation

Front 58

What would be the effect of an impairment of both sympathetic and parasympathetic systems?

Back 58

Person would be unable to respond to changes in activity or environment

Front 59

What is the effect of high spinal cord injury (above T2)?

What remains, and what effect does it have?

Back 59

Loss of entire sympathetic outflow, sacral parasympathetic function

Excess in vagus parasympathetic function --> bradycardia

Front 60

What would be effected by a lesion to the conus medullaris?

Back 60

Sacral parasympathetics

Front 61

How is ANS tone maintained?

Back 61

Parsympathetic reflexes

Front 62

What is a simple reflex of the ANS?

Back 62

Local axon reflex where the sensory afferent (nociceptor) sends a collateral axon to dilate local blood vessels at the site of injury

Front 63

What are 3 examples of coordination in the autonomic ganglia?

Back 63

1. Paravertebral chain ganglia connected --> fire concertedly in fight or flight
2. Prevertebral ganglia and intrinsic plexuses in gut are reflex centers for GI tract in digestion
3. In physical activity, sympathetic activity increases --> decreased motility in gut, vasoconstriction

Front 64

What are three activities coordinated by the lumbar and sacral spinal cord?

Back 64

Micturition, defecation, sexual reflexes

Front 65

What are some events coordinated in the hypothalamus?

Back 65

Temp regulation, homeostasis of bp, limbic system, etc.

Front 66

What is the pathway of the baroreceptor reflex?

Back 66

Increase in bp --> carotid baroreceptor sends signal to nucleus of solitary tract --> signal sent to nucleus ambiguus --> signal to heart --> Ach released --> slows down heart rate

Front 67

What do inhibitory interneurons do in the baroreceptor reflex?

Back 67

High bp -> inhibitory interneurons project to sympathetics in thoracic cord (descending sympathetics) --> inhibits their tonic firing --> bp drops, heart slows

Front 68

What is a respiratory sinus arrhythmia?

Back 68

Fluctuations in heart rate caused by baroreflex response to changes in intrathoracic pressure when breathing

Front 69

What is vasovagal syncope?

Back 69

When increasing pressure on carotid sinus (straining to lift something for example) --> baroreceptor response --> decrease in bp and heart rate --> fainting

Front 70

What is the pathway of pupillary light reflexes?

Back 70

Retina --> pretectal nuclei (which also receive input from contralateral pretectal nuclei via posterior commissure) --> ipsilat and contralat. EW nucleus --> ciliary muscle

Front 71

What causes the consensual light reflex?

Back 71

Bilateral connection of the pretectal nucleus to both EW nuclei of CN 3

Front 72

What does the descending reticular formation control?

Ascending?

Back 72

muscular tone

Arousal (sleep-wake)

Front 73

What is affected by the rostral/lateral reticular formation?

Back 73

Pressor - accelerates heart rate, increases heart contractions, increases peripheral resistance

Also expirations

Front 74

What is affected by the medial and caudal reticular formation?

Back 74

Depressor area - decreases heart rate, etc.

Also an inspiratory center

Front 75

What is the pathway for the respiratory reflex?

Back 75

Afferents --> nucleus solitarius and medullary reticular formation by CN X --> ventral horn of cervical spinal cord (C3-C5) --> motoneurons that supply axons to phrenic

Front 76

What 2 factors does ventilation depend on?

Back 76

Respiratory rate
Tidal volume

Front 77

What do pulmonary stretch receptors sense and how do they participate in respiratory reflexes?

Back 77

Sense degree of lung inflation--> CNX --> solitary nucleus --> inhibits inspiratory center, breathing rate and tidal volume (w/ pneumotaxic center)

Front 78

What do chemoreceptors sense and how do they participate in respiratory reflexes?

Back 78

owered oxygen, increased CO2, acidosis --> sensed by chemoreceptors in carotid and aortic bodies --> vagus --> excitatory to respiration centers

Also stimulated by hypotension

Front 79

How does pain affect respiratory reflexes?

What if pain pathways are interrupted?

Back 79

Pain --> induces arousal response, respiratory stimulation

Can cause hypoventilation, which, when added to lack of tonic arousal signal, may lead to complete apnea in sleep

Front 80

How does irritation of the mucous membranes of the nose/respiratory passages lead to respiratory reflexes?

Back 80

Irritation in nose --> CN 1 and 5 --> sneezing (increased respiration)

Irritation in respiratory passages --> CN 9 and 10 --> coughing

Front 81

How do joint and muscle afferents participate in respiratory reflexes?

Back 81

Respiratory excitation in exercise

Front 82

Why can you consciously control your respiration rate?

Back 82

Pressor and depressor areas played upon by many cerebral cortical areas

Front 83

What is the effect of a bilateral diencephalon lesion or deep cerebral hemisphere lesion?

Back 83

Cheyne-Stokes breathing -- hyperpnea (deep breathing) alternating with apnea

Front 84

What is the affect of lesions to midbrain or rostral pons?

Back 84

Sustained, rapid panting (polypnea)

Front 85

What is the effect of lesions to the lower pontine tegmentum?

Back 85

apneustic breathing (prolonged, end-inspiratory pauses occur)

Front 86

What is the effect of lesions to the dorsal tegmentum of the medulla?

Back 86

Ataxic breathing, irregular pauses and shallow breaths

Front 87

What is the effect of large medullary lesions?

Back 87

Complete cessation of all respiratory function

Front 88

What 3 stimuli can elicit the vomiting response?

Back 88

Excessive vestibular stimulation (CN 8)

Stimulation of receptors in pharynx (CN 9 and 10)

Activation by chemical agents in CTZ

Front 89

Vomiting control region
a. input
b. output

Back 89

a. CTZ, nucleus solitarius
b. CN 10 --> relax gastroesophageal sphincter, contract abdominals

Front 90

What are some expected problems if deficit to sympathetic nervous system? (4)

Back 90

Horner's Syndrome
Orthostatic Hypertension
Exercise intolerance
Heat intolerance - failure to sweat

Front 91

What are some expected problems if deficit to parasympathetic nervous system? (3)

Back 91

1. Dry mouth/dry eyes
2. Sexual impairment (erectile dysfunction)
3. Fixed pupils - unable to accomodate