Autonomic nervous system

1. Autonomic nervousAutonomic nervous
systemsystem
‫الملح‬ ‫فاضل‬ ‫محمد‬ ‫ثامر‬ ‫حسان‬‫الملح‬ ‫فاضل‬ ‫محمد‬ ‫ثامر‬ ‫حسان‬
Group – B -Group – B -
Dr. Maha TalalDr. Maha Talal

2. THE NERVOUS SYSTEMTHE NERVOUS SYSTEM
 The nervous system is aThe nervous system is a complex part ofcomplex part of
the human bodythe human body concerned with theconcerned with the
regulation and coordinationregulation and coordination of bodyof body
activitiesactivities such assuch as movement, digestion ofmovement, digestion of
food, sleep, and elimination of wastefood, sleep, and elimination of waste
products.products.
The nervous system hasThe nervous system has two maintwo main divisionsdivisions::
the central nervous system (CNS) and thethe central nervous system (CNS) and the
peripheral nervous system (PNS).peripheral nervous system (PNS).

4.  Autonomic nervous systemAutonomic nervous system:: The component ofThe component of
the NS ( Nervous System) that functions below thethe NS ( Nervous System) that functions below the
conscious level, controlling several physiologicalconscious level, controlling several physiological
processes:processes:
1. Distribution of blood flow tissue perfusion1. Distribution of blood flow tissue perfusion
2. Regulation of blood pressure2. Regulation of blood pressure
3. Control of visceral smooth muscle ( bladder,3. Control of visceral smooth muscle ( bladder,
bowels)bowels)
4. Control of endocrine and exocrine glands4. Control of endocrine and exocrine glands
5. Control of metabolic energy (glycolysis, glucogenesis5. Control of metabolic energy (glycolysis, glucogenesis
etc)etc)

5. Autonomic nervous system divisionAutonomic nervous system division to :to :
1.1. Sympathetic orSympathetic or (adrenergic)(adrenergic)
(thoracolumber)(thoracolumber)
NeurotransmitterNeurotransmitter:: ))epinephrine,epinephrine,
norepnephrine)norepnephrine)
ReceptorReceptor : α1 ,: α1 , α2α2 ,, ββ1,1, ββ22
2. Parasympathetic or2. Parasympathetic or (cholinergic):(cholinergic):
(craniosacral)(craniosacral)
NeurotransmitterNeurotransmitter :(acetylcholine):(acetylcholine)
ReceptorsReceptors: M1, M2 , N1, N2: M1, M2 , N1, N2

8. NEURONAL INNERVATION TO ORGANSNEURONAL INNERVATION TO ORGANS

9.  Classify of autonomic nervous systemClassify of autonomic nervous system
 1.release of n.t1.release of n.t
 2.on structure2.on structure
 3.from origin3.from origin
 4.according to the receptor4.according to the receptor

10. INNERVATION AT MOST SITESINNERVATION AT MOST SITES

11.  Functionally,Functionally, the two arethe two are generallygenerally
antagonisticantagonistic..
 TheThe sympathetic divisionsympathetic division stimulatesstimulates
functions involved infunctions involved in “fight or flight”“fight or flight”
reactions (fear, anger, etc), whereas thereactions (fear, anger, etc), whereas the
parasympathetic divisionparasympathetic division stimulatesstimulates
more tranquil functions (“more tranquil functions (“rest-and-rest-and-
digest”).digest”).

12.  NeurotransmittersNeurotransmitters are chemicalare chemical
substances called neurohormones.substances called neurohormones.
 These are released at the nerve endingsThese are released at the nerve endings
that facilitate the transmission of nervethat facilitate the transmission of nerve
impulses.impulses.

13.  Norepinephrine (mainly) and epinephrineNorepinephrine (mainly) and epinephrine
(in adrenal gland)(in adrenal gland) released at thereleased at the
postganglionic sympathetic neuronpostganglionic sympathetic neuron . These. These
neurons are also called ‘Adrenergic’.neurons are also called ‘Adrenergic’.
 ..

15.  Cholinergic Nervous System:Cholinergic Nervous System:
Acetylcholine neurotransmitter releasing nerve fibersAcetylcholine neurotransmitter releasing nerve fibers
(parasympathetic).(parasympathetic).
Acetylcholine is the preganglionic neurotransmitter in
the sympathetic system.
A few sympathetic (sweat glands and salivary glands)
have Acetylcholine as the postganglionic
neurotransmitter

16. ParasympatheticParasympathetic
Nervous SystemNervous System

17. Parasympathetic:Parasympathetic:
TheThe parasympathetic nervous systemparasympathetic nervous system helpshelps
conserve body energyconserve body energy and is partlyand is partly
responsible for such activities asresponsible for such activities as slowing theslowing the
heart rate, digesting food, and eliminatingheart rate, digesting food, and eliminating
body wastes.body wastes.
The ganglia are usuallyThe ganglia are usually close to or embeddedclose to or embedded
in the target organ.in the target organ.
AcetylcholineAcetylcholine is both preganglionic andis both preganglionic and
postganglionic neurotransmitter (Cholinergic).postganglionic neurotransmitter (Cholinergic).

18.  Biologic responses to parasympatheticBiologic responses to parasympathetic
stimulation:stimulation:
 Constriction of pupil (miosis), ciliary bodyConstriction of pupil (miosis), ciliary body
(“accommodation” of lens)(“accommodation” of lens)
 Contraction of smooth muscle in the GIContraction of smooth muscle in the GI
(“peristalsis”) and urinary tract(“peristalsis”) and urinary tract
 Constriction of the bronchiolesConstriction of the bronchioles
(“bronchoconstriction”)(“bronchoconstriction”)
 Slowing of heart rate (“bradycardia”)Slowing of heart rate (“bradycardia”)
 Increased secretion by the glandsIncreased secretion by the glands

19. Acetylcholine releaseAcetylcholine release in cholinergicin cholinergic
neuron involve 6 stepsneuron involve 6 steps::
1.1. Synthesis of AchSynthesis of Ach
2.2. Storage of Ach in vesiclesStorage of Ach in vesicles
3.3. Release of AchRelease of Ach
4.4. Binding to receptorBinding to receptor
5.5. Degradation of AchDegradation of Ach
6.6. Recycling of cholineRecycling of choline

20. AGENTS AFFECTINGAGENTS AFFECTING
CHOLINERGIC TRANSMISSIONCHOLINERGIC TRANSMISSION
HemicholiniumHemicholinium
LatrotoxinLatrotoxin
VesamicolVesamicol
Botulinus toxinBotulinus toxin
CalciumCalcium
PhysostigminePhysostigmine
AtropineAtropine
d-Tubocurarined-Tubocurarine

22. DRUG ACTING ONDRUG ACTING ON
A.N.SA.N.S
 1- cholinergic drugs1- cholinergic drugs
A- Parasympathomimetic DA- Parasympathomimetic D
B- Parasympathlytic DB- Parasympathlytic D
 2-2- adrenergic drugsadrenergic drugs
A- sympathomimetic DA- sympathomimetic D
B- sympatholytic DB- sympatholytic D

23. Parasympathetic drugs :Parasympathetic drugs :
 A- Parasympathomimetic DA- Parasympathomimetic D
Cholinergic agonist:Cholinergic agonist: Agents that bind toAgents that bind to
acetylcholine receptors and stimulates theacetylcholine receptors and stimulates the
parasympathetic systemparasympathetic system
(“parasympathomimetic”).(“parasympathomimetic”).
 B- parasympathlytic DB- parasympathlytic D
Cholinergic antagonistCholinergic antagonist: Agents that bind to: Agents that bind to
acetylcholine receptors but exhibit no intrinsicacetylcholine receptors but exhibit no intrinsic
activity (“parasympatholytic” – competitive toactivity (“parasympatholytic” – competitive to
endogenous Ach)endogenous Ach)

24. Parasympathomimetic drug:Parasympathomimetic drug:
1-1- direct acting cholinergic agentdirect acting cholinergic agent
2- Indirect acting cholinergic agent:2- Indirect acting cholinergic agent: divideddivided
into reversible irreversibleinto reversible irreversible

25. ParasymathomimeticParasymathomimetic
drugdrug
direct
Cholin esterase
Naturally occurrence
alkaloid

26. A-A- cholin esterasecholin esterase
1-Acetylcholine1-Acetylcholine
 Prototypical muscarinic (and nicotinic) agonist,Prototypical muscarinic (and nicotinic) agonist,
Nonselective action.Nonselective action.
 poor therapeutic agent.poor therapeutic agent.
 Chemical/enzymatic instability; LowChemical/enzymatic instability; Low
bioavailability (poorly absorbed); Quick onsetbioavailability (poorly absorbed); Quick onset
and short duration of action.and short duration of action.
 Use: In ocular surgery, causes completeUse: In ocular surgery, causes complete
miosis in seconds.miosis in seconds.

27.  Effect of ACH :Effect of ACH :
1.on the intestine1.on the intestine : Increase S.M contraction: Increase S.M contraction
2.on the urinary tract2.on the urinary tract : Increase in muscle: Increase in muscle
tone and contractiontone and contraction
3. on blood vessels3. on blood vessels : vasodilatation: vasodilatation

28. 4.on the4.on the secretary glandsecretary gland :increase secretion:increase secretion
5. on the5. on the S.M of tracheaS.M of trachea :contract , increase:contract , increase
bronchial secretion,bronchial secretion, bronchoconstriction ,
6.on the skeletal Muscle : increase Muscle
tone
7. On the heart : bradycardia
8. On the eye : miosis , decrease in I.O.P
9 .On the adrenal gland