L23: Autonomic Nervous System Flashcards

1
Q

ANS effect on visceral functions

A

can change functions rapidly and intensely

HR can be increased w/in 3-5 seconds

arterial press can be doubled in 10-15 seconds

sweating can begin w/in seconds

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2
Q

generalizations of ANS

A
  1. terminal ends of these fibers are enlarged where NTs and mito are stored
  2. efferent activity of ANS is mostly regulated by reflexes
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3
Q

ANS pathways consist of 2 neurons in sequence

A
  1. preganglionic neuron
    - -cell bodies w/in CNS
    - -axons myelinated
    - -ACH
  2. postganglionic neuron
    - -cell bodies in peripheral ganglia
    - -not myelinated
    - -ACH in parasymp
    - -norepi in symp sys
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4
Q

sympathetic glands

A

causes secretion of large amounts of sweat

cholinergic to most sweat glands – symp via ACH

this is a parasympathetic function distributed via sympathetic fibers

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5
Q

parasympathetic glands

A

strongly stims:
lacrimal, nasal, salivary, upper GI glands

(lower GI glands mostly stim by enteric sys)

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6
Q

effects of ANS stimulation on heart

A

sympathetic
–increases HR, contraction strength

parasym
–decrease HR, contraction strength

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7
Q

effects of ANS stimulation of systemic BVs

A

symp
–constriction

parasym
–no effect

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8
Q

effects of ANS stimulation on arterial pressure

A

symp
–acute increase in press but no long term effect

parasym
–decrease pumping of heart but little effect of bp

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9
Q

general effects of ANS stimulation

A

symp
–inhibits most endodermal structures

parasym
–excites most

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10
Q

effects of ANS stimulation on eyes

A

sym
–pupil dilation

para

  • -pupil constriction
  • -lens focusing
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11
Q

effects of ANS stimulation on GI tract

A

sym

  • -strong stim inhibits peristalsis
  • -GI tract normally not dependent on symp stim

para

  • -promotes digestion
  • -relaxes sphincters
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12
Q

cell body of each sympathetic preganglionic neuron lies in ?

A

intermediolateral horn of spinal cord

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13
Q

all sympathetic preganglionic neurons are ?

A

cholinergic

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14
Q

postganglionic sympathetic fibers

A
pass thru gray rami
C type fibers
innervate muscle to:
--constrict BVs
--piloerect hair
--change HR
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15
Q

cervical sympathetic chain

A

supplies face and thoracic viscera
–considered postsynaptic

postganglionics are from cervical ganglia and T1-5 paravertebral ganglia

they exit chain as direct fibers and travel down to thorax as cardiopulmonary splanchnic nerves

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16
Q

cardiopulmonary splanchnic nerves

A

travel on their own and do not accompany other nerves or vessels

function:
coronary art dilation
increase hr
bronchodilation

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17
Q

thoracic sympathetic chain

A

lies against neck of ribs and costovertebral junctions

12 thoracic ganglia pairs

  • -T2 to neck
  • -T3-6 to thorax
  • -T7-11 to abdomen
  • -T12-L2 to LE
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18
Q

stellate ganglion

A

first thoracic ganglion pair often fused w/ inf cervical ganglion going to head

collectively called stellate ganglion

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19
Q

splanchnic nerves – properties

A

composed of preganglionic fibers and visceral sensory fibers

supply abdominal viscera

synapse in prevertebral ganglia

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20
Q

splanchnic nerves

A
  1. greater, T5-9
    synapses in celiac ganglion
  2. lesser, T10-11
    sup mesenteric ganglion
  3. least, T12
    aorticorenal ganglion
  4. lumbar, L1-2
    sup and inf mesenteric ganglion
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21
Q

adrenergic alpha receptors

A

NE excites mainly alpha receptors but also beta to lesser extent (epi excites both)

functions:
vasoconstriction, iris dilation, GI relaxation, sphincter contraction

22
Q

adrenergic beta-1 receptor

A

cardioacceleration

increased myocardial strength

lipolysis

23
Q

adrenergic beta-2 receptor

A
vasodilation
intestinal relaxation
uterus relaxation
bronchodilation
calorigenesis
glycogenolysis
bladder relaxation
24
Q

adrenergic beta-3 receptors

A

thermogenesis

25
reserpine
blocks synthesis and storage of NE
26
propranolol
blocks sympathetic beta-1/2 receptors
27
metoprolol
blocks mostly sympathetic beta1 receptors
28
beta blockers -- properties
adrenergic beta receptor blocker increase actions of symp sys (decrease HR, contraction strength) anti-hypertension (alpha blockers decrease bp)
29
beta blockers - side effects
fatigue, hypotension, bradycardia associated w/ neg changes in blood lipid profiles associated w/ higher glucose and insulin levels
30
adrenal medulla
secretes epi and norepi --last hours when secreted by adrenal medulla but only seconds when secreted by neurons secretory cells are postganglionic neurons
31
alarm or stress response results in ?
mass discharge of entire sympathetic system fright, fear, severe pain, survival
32
75% of parasympathetic fibers are in the ?
vagus nerve CN X
33
parasym -- pre and post ganglionic fibers
pre fibers pass all the way to the organ to be innervated post fibers are located in wall of organ and use ACH
34
cranial nerves that carry parasym signals
3 -- oculomotor n 7 -- facial 9 -- glossopharyngeal 10 - vagus
35
parasym - sacral nerves
pass thru spinal nerve sacral plexus on each side ``` supplies: colon rectum urinary bladder external genitalia ```
36
oculomotor nerve
pregang --from edinger-westphal nucleus to ciliary ganglion postgang --from ciliary ganglion to sphincterpupillae muscle
37
CN III - function
oculomotor n motor: --innervates skeletal muscles of the eye parasym --constricts pupillae of the iris and ciliary muscles
38
facial nerve
pregang --from sup salivatory and lacrimal nuclei to submandibular/sublingual ganglia postgang --to lacrimal gland, submandibular gland, sublingual gland, mucous glands
39
CN VII -- functions
facial nerve motor --primary motor nerve to muscles of facial expression and inner ear sensory --taste from ant 2/3s of tongue parasym - -increase saliva flow - -stim nasal mucosa
40
glossopharyngeal nerve
pregang --inf salivatory nucleus to otic ganglion postgang --to parotid gland
41
CN IX -- functions
glossopharyngeal n general sensation of taste from post 1/3 tongue skeletal muscle to stylopharyngeus muscle
42
vagus nerve -- branches
``` cardiac branches pulmonary esophageal left recurrent laryngeal right recurrent laryngeal ```
43
CN X -- functions
lowers HR ``` --GI controls taste, saliva increase stomach acidity control blood glc balance assist bile release ``` --kidneys promote filtration reproductive -- help control fertility
44
vagus nerve dysfunction
``` IBS anxiety, depression high or low HR difficult to swallow esophageal reflux migraines ```
45
ACH synthesis
acetyl-CoA + choline = ACH enzyme -- choline acetyl transferase ACH ---> choline + acetate ion enzyme - acetylcholinesterase
46
ACH receptors
muscarinic ---found on effector cells stimed by postgang cholinergic neurons nicotinic - -found in autonomic ganglia at synapses btwn pre and postgang neurons - -present in skeletal muscles
47
ACH receptors -- channels
muscarinic works thru G proteins nicotinic uses ion channels
48
indirect parasym drugs
inhibit cholinesterase thus promoting ACH to live longer some indirect drugs used as chemical weapons such as tear gas/sarin
49
carbachol
binds muscarinic and nicotinic receptors primarily used to treat glaucoma
50
parasympathomimetic drugs
act like parasym sys not rapidly destroyed by cholinesterase act directly on muscarinic receptors include pilocarpine and methacholine
51
drugs that inhibit acetylcholinesterase
neostigmine pyridostigmine ambenonium
52
drugs that block cholinergic activity
atropine homatropine scopolamine