1 The Autonomic Nervous System - PowerPoint Presentation

Slide1

1

The Autonomic Nervous System

Def: The ANS consists of all visceral motor neurons innervating smooth muscle, cardiac muscle and glands.Slide2

Divide Autonomic Pharmacology into Four Categories:

1. Drugs that increase the sympathetic nervous system response

2. Drugs that increase the parasympathetic response

3. Drugs that block the sympathetic nervous system response

4. Drugs that block the parasympathetic response Slide3

Sympathetic Nervous System Adrenaline Rush Autonomic nervous system response to fear, anger, stress Slide4

Parasympathetic Nervous System Rest and Digest Relax, Repair, Renew Slide5

Sympathetic Parasympathetic

Agonist

Antagonist Slide6

Sympathetic Parasympathetic

Agonist

Antagonist Slide7

Sympathetic Parasympathetic

Agonist

Antagonist Slide8

Autonomic Nervous System Autonomic means automatic You do not control your ANS, it works automatically

Controls the functions of MANY organs automatically That’s why many drugs that affect the ANS affect many organs Slide9

Drugs that increase the sympathetic nervous system response.

Sympathomimetic – mimic, imitate the sympathetic nervous system response Slide10

Drugs that increase the parasympathetic nervous system response.

Parasympathomimetic – mimic, imitate the parasympathetic nervous system response Slide11

Drugs that decrease the sympathetic nervous system response.

Sympatholytic – decrease or block the sympathetic nervous system response Slide12

Drugs that decrease the parasympathetic nervous system response.

Parasympatholytic – decrease or block parasympathetic nervous system response Slide13

Drugs that affect the ANS will affect many organs:

Heart Lung airways Blood vessels Bowels

Pancreas Ureters Bladder Eyes Pupils

Lacrimal gland

Salivary glands Slide14

Do not confuse the autonomic nervous system with: Peripheral Nervous System Outside of skull and spinal cord

Neurons end on organs and muscle

Central Nervous System Brain and spinal cord Neurons end on other neurons Slide15

Do not confuse the ANS with Voluntary Nervous System Voluntary means willing, like to volunteer You do control your voluntary nervous system

You control your skeletal muscles to move your body Slide16

The autonomic nervous system is divided into two systems: Sympathetic

Adrenaline rush Fear, flight, fight Slide17

B. Parasympathetic rest, repair, digest Slide18

Can you guess what is happening to this girl’s organ function?Slide19

Running is voluntary in this case (she has no choice)



But everything else is automatic

Effects of epinephrine or adrenalin

(heart is pounding)Slide20

Adrenergic Receptors Heart is innervated by sympathetic neurons Norepinephrine – comes from the sympathetic neuron

The heart senses Adrenaline from Adrenal gland on top of the kidneysEpinephrine is adrenalin

Adrenergic Beta 1 receptors Slide21

Effects of Epinephrine – Adrenaline

Lung Airways WIDE OPEN BP is high – systemic vessels constrict Slide22

Adrenergic Receptors Blood vessel smooth muscle is innervated by sympathetic neuron Norepinephrine

Receptors also sense adrenaline from adrenal Epinephrine

Adrenergic Alpha 1 receptors Slide23

Adrenergic Receptors Lung bronchiole smooth muscle is innervated by sympathetic neuron Norepinephrine

Blood vessels sense adrenaline from adrenal Epinephrine

Adrenergic Beta 2 Receptors Slide24

Effects of Epinephrine – Adrenalin Blood to muscles increased Blood to GI decreased

Pupils dilated

Norepinephrine – neurotransmitter that dilates lungs, constricts blood vessels, lung airways open, shutting down GI tract Slide25

Why are all these changes occuring? Sympathetic nervous system (Norepinephrine)

Adrenal gland – on top of kidneys (that extra boost) Adrenalin (Epinephrine)

Adrenergic Neurons or Adrenergic Agonist Adrenergic System Slide26
Slide27

Adrenergic Agonists Adrenergic Agonist substances are also called

sympathomimetics Slide28

Epinephrine or Adrenaline Adrenaline is an adrenergic agonist

- increased heart rate - constricts blood vessels

- dilates lung airways - dilates pupils Slide29

Albuterol Is an adrenergic beta agonist used in asthma, what are some of its other effects besides bronchodilation

?Increased heart rate Increased blood pressure Slide30

Adrenergic Antagonists Beta blockers are common drugs used to treat high blood pressure Beta blockers are common drugs used to treat high eye pressures (glaucoma) Slide31

Asthma Do you understand why beta blockers can make asthma worse?That’s why one of the reasons we try to use

cardioselective beta blockers in patients with asthma Slide32

Autonomic Nervous System Although we have discussed many organ functions We have only discussed HALF of the Autonomic Nervous System

The other half does the opposite Slide33

Can you guess what is happening to his heart rate? His blood pressure? Slide34

Effects of parasympathethic tone

This is the rest and digest system - Acetylcholine – neurotransmitter - Muscurinic receptors

Slide35

Parasympathetic Nervous System

Cholinergic Agonism Cholinomimetic

Rx: Bethanecol - cholinergic muscurinic agonist - used to stimulate bowel and bladder function

Slide36

Indirect Cholinergic Agonism Acetylcholinesterase

inhibitors Blocking the breakdown of acetylcholine increases acetylcholine levels Acetylcholineterase

inhibitors are cholinomimeticRx: Neostygmine Toxin: Organophosphate – acetylcholinesterase inhibitors

Slide37

Cholinergic Antagonism Rx: Atropine – classic cholinergic antagonist

Cholinergic muscuranic antagonist Anticholinergic

Antimuscuranic Slide38

Rx: Atropine

Speeds up heart rate

Emergency treatment for

bradycardia

(slow heart rate)

Atropine also causes

mydriasis

Atropine used for

diarrhea

Atropine used as antidote for organophosphate poisoning Slide39

Asthma Beta agonists are used in asthma

But so are cholinergic

muscuranic blockers Slide40

DuoNeb

for Asthma contain two drugs

Rx:

Albuterol

– beta2 agonist

- sympathomimetic

Rx: Ipratropium – anticholinergic

-

antimuscarinic

-

parasympatholytic

Slide41

Heart rate up or down Blood pressure up or down

Eye pressure up or down Lung airways open or closed

Bladder relax or less relaxed GI stimulate or slow Slide42

Dilating the pupils is – Mydriasis Slide43

Dilating the pupils is – Mydriasis

Both

Sympathomimetic adrenergic drugs

and

Anticholinergic

parasympatholytic

drugs

cause

mydriasis

Slide44

Constricting the pupils is Miosis Slide45

Both sympatholytic adrenergic antagonist drugs and

- Cholinergic parasympathomimetic drugs cause miosis Slide46

Dry lacrimal glands Both sympathomimetic adrenergic drugs

And Anticholinergic parasympatholytic drugs

Cause dry eyes Slide47

Stimulate lacrimal glands to make tears Both sympatholytic adrenergic antagonist drugs

and Cholinergic parasympathomimetic

drugs Stimulate tear production Slide48

Dries salivary glands

Both sympathomimetic adrenergic drugs And Anticholinergic parasympatholytic drugs

Cause dry mouth Slide49

Stimulates salivary glands to make saliva Both sympatholytic adrenergic antagonist drugs

and Cholinergic parasympathomimetic

drugs Stimulate saliva production Slide50

Both sympathomimetic adrenergic drugs

And Anticholinergic parasympatholytic drugs

Dry respiratory airways Slide51

Both sympatholytic adrenergic antagonist drugs

And cholinergic parasympathomimetic drugs Can stimulate airway secretion Slide52

Bronchodilation: relaxing bronchiole smooth muscle to open airways

Both sympathomimetic adrenergic drugs and

Anticholinergic parasympatholytic drugs Cause bronchodilation and are used in asthma Slide53

Bronchoconstriction/Bronchospasm: contracting bronchiole smooth muscle to close or constrict airways Slide54

Both sympatholytic adrenergic antagonist drugs

And Cholinergic parasympathomimetic drugs

Can cause bronchospasm Slide55

Drugs that cause tachycardia (fast heart rate) are called positive chronotropes

Both sympathomimetic adrenergic drugs

And Anticholinergic parasympatholytic drugs Cause tachycardia Slide56

Drugs that increase the force of contraction are positive inotropes Slide57

Sympathomimetic adrenergic drugs are positive inotropes Slide58

Drugs that cause bradycardia (slow heart rate) are called negative chronotropes Slide59

Both sympatholytic adrenergic antagonist drugs

And Cholinergic parasympathomimetic drugs can cause bradycardia Slide60

Drugs that decrease the force of contraction are negative inotropes Slide61

Sympatholytic adrenergic antagonist drugs are negative inotropes Slide62

Vasoconstriction: contracting arteriole smooth muscle to raise blood pressure Slide63

Sympathomimetic adrenergic drugs raise blood pressure by vasoconstriction Slide64

Vasodilation: relaxing arteriole smooth muscle to drop blood pressure Slide65

Sympatholytic adrenergic antagonist drugs can drop blood pressure Slide66

Some drugs relax the GI tract and slow peristalsis Slide67

Both sympathomimetic adrenergic drugs

And Anticholinergic parasympatholytic drugs

Slow peristalsis, relax GI Slide68

Some drugs stimulate peristalsis in the GI tract Slide69

Cholinergic parasympathomimetic drugs are used to stimulate GI Slide70

Drugs that affect autonomic nervous system may affect the pancreas Slide71

Some drugs relax the bladder and urinary tract smooth muscle and slow peristalsis Slide72

Both sympathomimetic adrenergic drugs and anticholinergic parasympatholytic drugs slow ureter peristalsis and relax bladder Slide73

Some drugs stimulate the smooth muscle of the bladder and urinary tract, increasing peristalsis Slide74

Cholinergic parasympathomimetic drugs are used to stimulate the bladder Slide75

75Slide76

76

Sympathetic and Parasympathetic Divisions of the ANS

How they are similar:

Both divisions are part of the ANS

Both have effects on smooth muscle, cardiac muscle and glands

How they differ:

Stimulation of effectors by each system vary from one body system to another. Effects may be stimulatory or inhibitory.

Location

Length of pre and postganglionic fiber

Neurotransmitters usedSlide77

77

Comparison of ANS and Somatic Motor Pathways

Somatics

Single neuron from spinal cord to effector

One neuron innervates the effector cell

NTS is acetylcholine (ACh)

Autonomics

Two neurons relay (ganglion) to effector

Dual innervation of effectors

NTS at ganglia (ACh); NTS at effector can be ACh or norepinephrine Slide78

Location and neurotransmitters used by Sympathetic/Parasymp

sympathetic

parasympathetic

preganglionic neuron

postganglionic neuron

nicotinic receptors

muscarinic receptors

adrenergic receptorsSlide79

Characteristics of Sympathetic and Parasympathetic FunctionPost-ganglionic sympathetic nerves release norepinephrine at their nerve endingsthese nerves are called adrenergic nervesPre and post-ganglionic parasympathetic nerves release acetylcholine at their nerve endings (Nitric oxide- corpora cavernosa)‏these nerves are called cholinergic nervesEXCEPTION FOR SYMPATHETIC:Cholinergic: mACH; used in body wall.Vasodilation of vessels in brain and skeletal muscle Piloerector muscles

Sweat glandsNitric oxide: vasodilation of vessels in brain, skeletal muscleSlide80

80

Sympathetic

Nervous System

“Thoracolumbar”

Figure 60-1;

Guyton & Hall

When active?

Length of pre and postganglionic nerve?

Location of cell bodies of preganglionic nerve?

Location of cell bodies of postganglionic nerve?

Neurotransmitters released?

Adrenal medullaSlide81

81

Lipolysis and thermogenesis

Adipose tissue



3

Inhibitory, relaxation of resp. tract to get dilation

Respiratory tract

, GI, glands, hepatocytes



2

Increased heart rate and inotropy

HEART

, kidney, adipocytes



1

Presynaptic control/ release of NT

Vascular endothelium



2c

Increase vasoconstriction (increased MI mortality w/polymorphism)

‏

Vascular endothelium



2b

Lipid metabolism

Vascular endothelium and adipocytes



2a

Increased BP, vasoconstriction

Arteries

, heart



1B

Increased inotropy, closure of GI sphincters, vasoconstriction, pupil dilation

Iris

,

intestine

, heart and arteries



1a

Actions

Where found?

ReceptorSlide82

82

Parasympathetic

Nervous System

“cranio-sacral”

Parasympathetic nerves originate from cranial nerves III, VII, IX, and X and the sacral spinal cord.

occulomotor nerve

- fibers to the pupillary sphincters and ciliary muscle

facial nerve

- fibers to lacrimal and submandibular gland

glossopharyngeal nerve

- fibers to parotid gland

vagus nerve

- motor inputs to visceral organs

sacral segments

- fibers to descending colon, rectum, bladder and genitalia

Figure 60-3;

Guyton & HallSlide83

Effects of the ANS on the Organseyesympathetic --pupillary dilation (alpha 1 receptor)‏parasympathetic--pupillary constriction and accommodation (focusing) of the lens (mACh receptor)‏glands of the bodyparasympathetic stimulate the nasal, lacrimal, salivary, and G.I. glands (mACh receptor)‏sympathetic stimulates the sweat glands (mACh receptor)‏Slide84

Effect of the Autonomic Nervous System on the OrgansG.I. tractparasympathetic stimulates overall activity including G.I. smooth musclesympathetic has very little effectheartsympathetic increases the rate and contractilityparasympathetic decreases heart rateblood vesselssympathetic causes vasoconstriction. Reduced sympathetic response accounts for most vasodilation.parasympathetic causes some vasodilation (e.g., penis)‏Slide85

Sympathetic and Parasympathetic “Tone”the basal rate of activity of each systemthis background activity allows for an increase or decrease in activity by a single system sympathetic tone normally causes about a 50 % vasoconstrictionincreasing or decreasing “tone” can change vessel diameterparasympathetic tone provides background G.I. activitySlide86

adrenergic or sympathomimetic drugs act like norepinephrinethese drugs have an effect which is much more prolonged than that of either norepinephrine phenylephrine stimulates alpha receptorsisoproterenol stimulates both beta1 and beta2 receptorsalbuterol stimulates only beta2 receptorssome drugs act indirectly by increasing the release of norepi from its storage terminalsephedrine, amphetamine, pseudoephedrine, Slide87

Pharmacology of the Sympathetic Nervous Systemdrugs that block the effect of norepinephrine alpha blockersphentolamine Cheap Viagra!beta blockersbeta1 and 2 - propranololSlide88

Pharmacology of the Parasympathetic Nervous Systemparasympathomimetic drugsmuscarinepilocarpineactivates muscarinic receptors, cause profuse sweating (why if sweat glands are controlled by sympathetic system?)‏cholinesterase inhibitorsneostigmine, potentiates the effect of acetylcholineantimuscarinic drugsatropine blocks the effect of acetylcholine on effector cells