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Flashcards in Autonomic Nervous System Deck (118):
1

Central Nervous System (CNS)

Includes brain and spinal cord
• Integrates all body activities

2

Peripheral Nervous System

Somatic Nervous System
Autonomic Nervous System (ANS)
• Parasympathetic nervous system (PNS)
• Sympathetic nervous system (SNS)

3

What does SNS do?

 Activates skeletal muscle contraction
 Consists of motor neurons/sensory neurons
 Sensory (afferent) – go TO CNS
 Motor (efferent) - go FROM CNS to skeletal muscle
 VOLUNTARY

4

What does ANS do?

 Further subdivided into PNS and SNS
 Regulates activity of smooth muscle, exocrine glands, cardiac tissue and certain metabolic activities
 Sensory neurons go from smooth muscle & cardiac muscle TO CNS
 Motor neurons go to glands, smooth & cardiac muscle FROM CNS
 Adjust to internal environment
 INVOLUNTARY

5

Enteric Nervous System (ENS)

• Aka 3rd division of ANS
• Network of autonomic nerves in gut wall
• Receives innervation from SNS & PNS and regulates GI motility and secretion
• Responds to Neurotransmitters – peptides and nitric oxide

6

In Neurotransmission of ANS, Preganglionic neuron & Postganglionic neuron are?

Preganglionic neuron – cell body in CNS, axon extends out of CNS
Postganglionic neuron – innervate an effector outside the CNS

7

In ANS, Whats ganglion?

Ganglion – Small mass of nerve tissue containing the cell bodies of neurons

8

In ANS whats synapse?

Synapse – space b/w pre & post neurons or space b/w post neuron & effector where Neurotransmitter (NT) is released

9

In ANS whats SNS primary NT?

SNS – primary NT is Norepinephrine (NE) – may also be referred to as noradrenaline (NA)

10

In ANS whats PNS primary NT?

PNS – primary NT is Acetylcholine (ACH)

11

ACH, the primary NT of PNS, is released where?

Released at ALL autonomic ganglia (PNS & SNS), at PNS neuroeffector junction (nej), somatic neuromuscular junction (nmj), and some SNS nej ..ach is everywhere..

12

NE/Noradrenaline, primary NT of SNS is released where?

Norepinephrine/Noradrenaline (NE/NA) – Primary NT of SNS. Released at most SNS nej***

13

What releases EPI?

Released from adrenal medulla in response to activating SNS

14

What is Dopamine(DA) important for & where is it released?

important NT in CNS, and released at several peripheral SNS fibers

15

Parasympathetic has

Parasympathetic has the LONG preganglionic nerve and SHORT post-ganglionic nerve(EFFECTOR)*

16

Sympathetic has

Sympathetic has the SHORTER preganglionic and LONGER post-ganglionic

17

PNS & SNS have

ACH is at both of these synapses in ganglion to jumpstart the next neuron* HOWEVER, Neuroeffector Junction (NEJ) is ACH for PNS & NA for SNS*

18

ACH NT is

1. Synthesis of ACH ( Transport of choline is inhibited by hemicholinium)
2. Uptake into storage vesicles (ACH is projected from degradation in the vesicle)
3. Release of NT (blocked by Botulinum toxin, Spider venom causes release of ACH)
4. Binding to the receptor (postsynaptic receptor is activated by binding of the NT)
5. Degradation of ACH (ACH is rapidly hydrolyzed by acetyl- cholinesterase in the synaptic cleft.
6. Recycling of Choline ( choline is taken up by the neuron)

19

NE NT is

1. Synthesis of NE (hydroxylation of tyrosine is rate-limiting step)
2. Uptake into storage vesicles ( dopamine enters a vesivle & is converted into NE, NE is protected from degradation in the vesicle, transport into the vesicle is inhibited by reserpine)
3. Release of NT (influx of Ca2+ causes the fusion of vesicle with the cell membrane in a process known as exocytosis, release is blocked by guanethidine & bretylium)
4. Binding to receptor (postsynaptic receptor is activated by the binding of NT)
5. Metabolism (NE is methylated by COMT & oxidized by MAO)
6. Removal of NE ( released NE is rapidly taken into the neuron, reuptake is inhibited by cocaine & imipramine)

20

Feedback inhibition

BINDS TO PREVIOUS SYNAPSE AND BY RELEASING IT SHUTS DOWN ! BINDS AND KNOWS WE DON’T NEED IT ANYMORE* MAYBE ITS MAKING IT RELEASE MORE VERY COMMON….BY DECREASING COCAINE OR WHATEVER..

21

What are other NT called found in ANS

nonadrenergic noncholinergic neurons (NANC)

22

NANC are found?

Primarily found in enteric nervous system of GI tract, genitourinary tract, airways and some blood vessels

23

NANC include

Includes peptides, ATP, GABA, substance P, nitric oxide, serotonin

24

In PNS what are your responses?

• Responses are specific normally happening*
• Rest & digest
• Miosis*
Increase in GI motility/salivation
Increase in urination/defecation
Decrease in HR
Bronchoconstriction
Erection

25

In SNS what are your responses?

• Responses are diffuse.. Whole thing is activated NONSPECIFIC
• Fight or flight
• Mydriasis
Decrease GI motility/salivation
Decrease urination/Defecation
Increase in HR
Bronchodilation
Ejaculation

26

Is PNS or SNS more dominant?

PNS because it acts to oppose or balance SNS !
Not a functional entity and does not act as a complete system
 Fibers are activated separately to affect specific organs such as stomach or eyes

27

Pupil receptor for adrenergic is

Alpha 1, SNS effect is mydriasis

28

Pupil receptor for Cholinergic is

Muscarinic, PNS effect is Miosis

29

HR receptor for adrenergic is

Beta 1, SNS effect is increase HR

30

HR for cholinergic is

Muscarinic, PNS effects decrease HR

31

Arteries/veins receptor for adrenergic is

SNS effects
Alpha 1- constriction
Beta 2 - DIlation

32

Arteries/veins receptor of cholinergic is

Muscarinic, PNS effect is dilation

33

Smooth muscle receptor of adrenergic is

Beta 2, SNS effect is decrease in motility

34

Smooth muscle receptor of cholinergic is

Muscarinic, PNS effect is increase in motility

35

Gastric secretion adrenergic receptor is

Beta, SNS effect is inhibit

36

Gastric secretion cholinergic receptor is

muscarinic, PNS effect stimulates

37

Pancreas adrenergic receptor is

Alpha, SNS effect inhibits

38

Pancreas cholinergic receptor is

Muscarinic, PNS effect stimulates

39

Salivary secretion adrenergic receptor is

Alpha 1- Inhibit
Beta- inhibit

40

Salivary secretion cholinergic receptor is

muscarinic, PNS effect stimulates

41

Liver adrenergic receptor is

Alpha 1- Glycogenolysis
Beta 2- Gluconeogenesis

42

Liver cholinergic receptor is

Muscarinic which stimulates glycogenesis

43

Cholinergic receptors such as ACH or Muscarinic receptors are located?

PNS nej, some SNS nej (sweat glands), CNS, and autonomic ganglia
- FOUND IN BODY IN GREATER #'s

44

What are the effects of stimulating the muscarinic receptors?

SLUDGE
• Salivation
• Lacrimation
• Urination
• Defaction
• GI motility

45

Nicotinic receptors which are activated by ACH & nicotine are located?

Located on autonomic ganglia and when activated will excite neurotransmission
Located at somatic neuromuscular junction and when activated will mediate muscle contraction
• Nicotinic have some opposing effects of muscarinic (tachycardia, HTN)

46

Alpha 1 adrenergic receptors

• constricts vascular smooth muscle
• constricts blood vessels
• Increase basal metabolic rate
• Located at SNS nej(neuroeffective junction) effector (primarily smooth muscle)

47

Alpha 2 adrenergic receptors

• Inhibition of NE release from nerve endings at pre synaptic post ganglionic neuron (negative feedback)
• Also located on some postsynaptic tissue & blood platelets
- activating Alpha 2 decreases HR because blocks alpha 1

48

Beta 1 adrenergic receptors

• Mediates cardiac stimulation ( HR & contractility)
• Located on SNS effector (cardiac muscle, vascular smooth muscle, renal cells -  renin release) … why does Sym want HTN? Vasoconstriction keeps the blood in the muscles in the peripherys*
• Increased lipolysis

49

Beta 2 adrenergic receptors

• Mediates smooth muscle relaxation
• Located on SNS effector (bronchioles in lung, uterine smooth muscle and vascular smooth muscle)
• In liver and muscle – mediate glycogenolysis … more creating glycogen into glucose*

50

Direct Agonists

Activate postsynaptic receptors

51

Indirect agonists

• Stimulate release of NT
• Inhibit reuptake of NT
• Inhibit metabolism of NT

52

Direct antagonists

Block postsynaptic receptors SHUTS DOWN normal receptor between NT and receptor*

53

Indirect antagonists

• Inhibit synthesis of NT
• Prevent vesicular storage of NT
• Inhibit release of NT

54

Direct agonists will

bind and activate cholinergic receptors
-choline esters and plant alkaloids

55

Indirect agonists will

increase synaptic concentrations of ACH
- cholinesterase inhibitor

56

Direct cholinergic agonists like choline esters are ACH and Carbachol which will

activate both nicotinic and muscarinic. ACH has limited clinical indications
- lack of specificity for muscarinic subtypes, effects many organ systems

57

Bethanechol and methacholine

Direct cholinergic agonist
- activates only muscarinic. Methacholine not commercially available

58

Bethanechol (Urecholine)

Direct cholinergic agonist
o acts at muscarinic only*
o Stimulates bladder w/o significant effects on HR or BP
o TX of urinary retention post-op & post partum

59

Carbachol (Isoptocarbachol, Miostat)

Direct cholinergic agonist
o For chronic open-angle glaucoma
o Produce miosis during ophthalmic surgery

60

Muscarine

DIRECT CHOLINERGIC AGONISTS (PLANT ALKALOIDS)
- no current med use

61

Nicotine

DIRECT CHOLINERGIC AGONISTS (PLANT ALKALOIDS)
- smoking cessation

62

Pilocarpine (Isoptocarpine, Ocusert, Salagen)

Direct cholinergic agonists (plant alkaloid)
• Higher affinity for muscarinic receptor
• Treats glaucoma: stimulate contraction of ciliary muscle fibers   increase aqueous humor outflow
decrease in Intraocular pressure

63

Cevimeline (Exovac)

• To treat dry mouth associated with Sjogren’s syndrome

64

MOA

Cholinesterase inhibitor
- Inhibit breakdown of ACH at all cholinergic synapses increase ACH concentration

65

Donepezil (Aricept)

Cholinesterase inhibitor - REVERSIBLE
Tx of Alzheimer's Disease

66

Edrophonium (enlon)

Cholinesterase inhibitor- REVERSIBLE
very short DOA. Used in Dx of Myasthenia gravis

67

Neostigmine (prostigmin)

Cholinesterase inhibitor- REVERSIBLE
Tx of Myasthenia gravis, antidote for skeletal muscle relaxants

68

Physostigmine (eserine)

Cholinesterase inhibitor - REVERSIBLE
Tx Overdoses of drugs with anticholinergic effects (i.e. atropine, TCAs)

69

Pyridostigmine (mestinon)

Cholinesterase inhibitor - REVERSIBLE
Tx of Myasthenia gravis

70

Irreversible cholinesterase inhibitor like

Organophosphates will  Bind covalently to acetyl cholinesterase resulting in a long lasting increase of acetylcholine

71

Ecothiophate (Phospholine)

Cholinesterase inhibitor- IRREVERSIBLE
Tx of chronic refractory glaucoma. DOA of up to one week

72

Pesticides (palathion and malathion)

Cholinesterase inhibitor- IRREVERSIBLE

73

Soman (chemical warfare agent)

Cholinesterase inhibitor- IRREVERSIBLE

74

Organophosphate poisoning is when

Augmented cholinergic Nuerotransmission in central and periphery synapses !
all effects of muscarinic activation
SLUDGE, spasm, bronchoconstriction, decrease HR & CO

75

Cholinergic activation in CNS & Excessive activation of nicotinic receptors

From organophosphate poisoning like seizures, respiratory depression, coma
o Neuromuscular blockade depolarized cell no more signals & muscle paralysis

76

What is the tx for organophosphate poisoning?

o Symptomatic - maintain VS(VITALS)
o Decontamination
OR
Antidotes- Use Atropine to counteract ACH and pralidoxime (2-PAM) to regenerate cholinesterase

77

Atropine*, Scopalamine

Muscarinic receptor antagonists, semi synthetic

78

o Ganglionic blockers
o Neuromuscular blockers – “curium”
o Depolarizing neuromuscular blocker - succinylcholine

Nicotinic receptor antagonists

79

BellaDonna Alkaloids

Muscarinic receptor antagonists- Atropine, scopolamine, hyoscyamine

80

ipratropium, tolterodine, oxybutynin, propantheline, dicyclomine, benztropine, etc

Synthetic/semi synthetic which are muscarinic receptor antagonists

81

• ipratropium (Atrovent)
• tiotropium (Spiriva)

Are bronchodilation meds which are muscarinic receptor antagonists!

82

Hysosamine, Donnatal, Dicyclomine

Tx for intestinal spasms/pain, GI & urinary tract & since they are muscarinic receptor antagonists they • Relax gi muscle, reduce intestinal motility, inhibit gastric acid secretion and urinary retention

83

oxybutynin, tolterodine, darifenacin, solifenacin

Tx for Dysuria & urinary incontinence since they are muscarinic receptor antagonists

84

(Scopolamine patch) behind the ear

Muscarinic receptor antagonist
TX of motion sickness by blocking cholinergic transmission from vestibular apparatus to vomiting center
- BAD CNS effects...sedation, confusion, altered mental status

85

(benztropine & trihexyphenidyl)

Muscarinic receptor antagonist
tx of parkinsons disease-reduce tremor
- BAD CNS EFFECTS.. sedation, confusion, altered mental status

86

Trimethaphan

Ganglionic blocker- Nicotinic receptor antagonist
- used rarely for HTN emergency

87

What are the two types of neuromuscular blocking agents?

nondepolarizing and depolarizing

88

o aka curariforms
o Atracurium, pancuronium, vecuronium

Nondepolarizing neuromuscular blocking agent
- o Competitive antagonist of ACH at nicotinic muscle receptors
o Causes muscle relaxation and paralysis
o Effects reversed by cholinesterase inhibitors… prevent ACH from being taken out so more of that competing with each other*

89

o Succinylcholine

Depolarizing neuromuscular blocking agent
o Causes “persistent” depolarization
o Used for surgery
o Effects not reversed by cholinesterase inhibitors therefore not antidote if an overdose

90

catecholamines & non catecholamines are

Direct acting agonists (adrenergic)

91

Amphetamine, cocaine, tyramine are

Indirect agonists (adrenergic)

92

Pseudoephedrine

mixed direct/indirect agonist (adrenergic)

93

Alpha 1 is for
Beta 1 is for

Vasoconstriction, increased BP, TPR
Cardiac stim
Vasodilation (skeletal muscle) & bronchiolar relaxation

94

What effects depend on affinity and specificity for type of adrenergic receptor?

Catecholamines is metabolized by MAO and COMT enzymes in gut, liver, other tissue - must give parenterally.

95

Epinephrine

Direct adrenergic agonist
Vasoconstriction and increase BP alpha 1
Cardiac stimulation Beta 1
Bronchodilation & skeletal muscle vasodilation Beta 2
Used in anaphylactic shock and cardiac arrest

96

NE

Direct adrenergic agonist
Vasoconstriction, increase BP Alpha 1
Cardic stim Beta 1
Used hypotension/shock

97

Isoproterenol- CATECHOLAMINE

Direct adrenergic agonist
Cardiac stim Beta 1
Bronchodilation Beta 2
Used in asthma, Av block, bradycardia

98

Dopamine- CATECHOLAMINE

Direct adrenergic agonist
Precursor to epi, NE
- Renal vasodilator (D1)
cardiac stim Beta 1
increase BP Alpha 1
Used to cardiogenic shock, septic shock, HF, adjunct to fluid, administration in hypovolemic shock

99

Dobutamine - CATECHOLAMINE

Direct adrenergic agonist
Highest affinity for beta 1
less activity at alpha 1
Used for cardiogenic shock, cardiac arrest, HF.. MOST EFFECT ON THE HEART

100

Phenylephrine -Non catecholamines

Direct adrenergic agonist
- Vasoconstriction
Increase BP
Mydriasis Alpha 1
NASAL DECONGESTANT, ocular decongestant & maintenance during sx

101

Albuterol -NON catecholamines

Direct adrenergic agonist
Bronchodilation Beta 2
Used in asthma, rescue inhaler/buffer, reverse constriction

102

Clonidine - Non- catecholamines

Direct adrenergic agonist
Inhibits NE release from nerve terminal of postganglionic neuron: feed back inhibition alpha 2… not ANTAGONIST, its an AGONIST because its activating alpha 2*
- Used to treat chronic hypertension
-Can have effects in CNS (sedation)

103

Terbutaline

- Bronchodilation and uterine relaxation (Beta 2)
- Used to TX asthma and premature labor (tocolytic)

104

Amphetamine

Indirect adrenergic agonist - - Increase the release of NE & DA from SNS neurons
- Vasoconstriction, cardiac stimulation and increase BP
- Penetrates CNS - CNS stimulation (increases mood and alertness (but decreases appetite)

105

Cocaine

Indirect adrenergic Agonist
- Local anesthetic
- Simulates SNS by blocking reuptake of NE & DA in the PNS & SNS – similar effects as amphetamine

106

Tyramine

Indirect adrenergic agonist
- Normal by-product of tyrosine metabolism in body
- Found in high concentrations in fermented foods such as certain cheeses, beers, red wine, certain cured meats (salami & pepperoni)
- Indirect sympathomimetic (mimicks sympathetic system) b/c it causes the release of stored catecholamines.
-Normally metabolized by MAO. So if taking an MAO inhibitor must avoid tyramine-containing foods.**** AVOID THIS IMPORTANT

107

What is mixed acting adrenergic agonist?

Cause vasoconstriction by binding to alpha 1

Increase release of NE from SNS neurons

108

Nasal decongestant called pseudoephedrine is

much more powerful affect* Claritin D antihistamine so its stops histamine, on mucus membrane then you don’t need pseud DIRECT AT ALPHA INDRECT EVERYWHERE ELSE**

109

Alpha adrenergic receptor antagonists

- nonselective alpha blockers--> block alpha 1 and 2 receptors
- selective alpha 1 blockers (azosin)

110

Beta adrenergic receptor antagonists (olol)

Nonselective Beta blockers
- selective Beta 1 blockers

111

Phenoxybenzamine

Nonselective alpha blocker
- noncompetitive, irreversible
- hypertensive episodes associated w/ pheochromocytoma (tumor of adrenal medulla that secretes catecholamines)

112

Phentolamine

Nonselective alpha blocker
-Competitive, reversible
- DX and TX hypertensive episodes from pheochromocytoma
Tx necrosis and ischemia from extravasations(leakage of a drug in surrounding tissues, so use drug to keeop it enclosed) of epinephrine

113

What drug relaxes smooth muscle and vascular smooth muscle in bladder/prostate while producing vasodilation and decrease BP?

Selective alpha 1 blockers
Used to treat hypertension(RARELLY) and urinary retention due to benign prostatic hyperplasia (BPH)

Agents include:
Doxazosin, Prazosin, Terazosin, Tamsulosin ALFUZOSIN only for BPH not for HTN more specific better*

114

What drug blocks Beta 1 receptors in heart, Beta 2 in smooth muscle, liver, tissues
decreasing BP, cardiac output, renin release, aqueous hypoglycemia?

Nonselective Beta blockers- treat htn, angina, arrhythmias, MI, angina, migraine, glaucoma

115

What are some non-selective Beta blockers?

Agents include: Propranolol, Nadolol, Timolol

116

Selective Beta 1 blockers

are selective for Beta 1 receptors (CARDIAC TISSUE)
- Produce less bronchoconstriction and other Beta 2 receptor mediated effects
- aka cardioselective Beta blockers

117

Atenolol, Metoprolol* are known as

Selective Beta 1 blockers

118

Carvedilol and Labetalol are

Mixed alpha and beta receptor antagonists
- Carvedilol- for HTN and CHF
- Labetalol - for HTN