Autonomic nervous system - Lazarov

Autonomic nervous systemAutonomic nervous system1.1. Autonomic nervous system (ANS) Autonomic nervous system (ANS) –– nomenclaturenomenclature2.2. Topographic organization and structural features of ANSTopographic organization and structural features of ANS3.3. Main subdivisions of the ANS:Main subdivisions of the ANS:

�� sympathetic nervous systemsympathetic nervous system�� parasympatheticparasympathetic nervous system�� enteric nervous systementeric nervous system

4.4. Sympathetic (thoracolumbar) nervous systemSympathetic (thoracolumbar) nervous system5.5. Parasympathetic (craniosacral) nervous systemParasympathetic (craniosacral) nervous system6.6. Enteric (intrinsic) nervous systemEnteric (intrinsic) nervous system7.7. Neurotransmitters, receptors and some ANS drugsNeurotransmitters, receptors and some ANS drugs8.8. Autonomic innervation of the eye and salivary glandsAutonomic innervation of the eye and salivary glands9.9. Autonomic plexuses in the thoracic cavity:Autonomic plexuses in the thoracic cavity:

�� cardiac plexuscardiac plexus�� pulmonary plexuspulmonary plexus�� thoracic aortic plexusthoracic aortic plexus

10.10. Autonomic plexuses in the abdomen Autonomic plexuses in the abdomen –– primary and secondaryprimary and secondary�� abdominal aortic plexusabdominal aortic plexus�� coeliac (solar) plexuscoeliac (solar) plexus

11.11. Autonomic plexuses in the pelvis Autonomic plexuses in the pelvis –– primary and secondaryprimary and secondary�� inferior hypogastric plexusinferior hypogastric plexus

Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 2

�� Autonomic Nervous System (ANS):Autonomic Nervous System (ANS):

� part of the peripheral nervous system

�� autonomicautonomic = auto (self) + nomos, = auto (self) + nomos, GrGr. . νόµοςνόµος (law)(law)

� reflex, involuntary actions

� automatic, independent, unconscious system

�� innervation of:innervation of:

�� visceraviscera

�� glandsglands

�� blood vesselsblood vessels

�� nonstriated (smooth and cardiac) musclesnonstriated (smooth and cardiac) muscles

�� synonyms:synonyms: visceral visceral (vegetative) (vegetative) nervous systemnervous system

� main function – control system to maintain life:

� regulation and control of visceral functions

� reproduction

� vital body processes – circulation, digestion, secretion and excretion etc.

Definition and nomenclatureDefinition and nomenclatureAutonomic nervous systemAutonomic nervous system

John Newport Langley John Newport Langley (1852(1852––1925)1925)


Structural organizationStructural organizationAutonomic nervous systemAutonomic nervous system

�� twotwo --neuron efferent system neuron efferent system (visceral(visceral efferentefferent neurons):neurons):� first (preganglionicpreganglionic ) ) neuronneuron – inside the CNS� second ((postganglionicpostganglionic ) ) neuronneuron – in ganglion

or plexus of neurons�� perikarya of visceralperikarya of visceral afferent neurons:afferent neurons:

� in dorsal root (spinal) ganglia


�� tripartite integrated systemtripartite integrated system(Langley, 1921):(Langley, 1921):

�� sympathetic nervous systemsympathetic nervous system

�� parasympathetic nervous systemparasympathetic nervous system

�� entericenteric nervousnervous systemsystem (ENS)(ENS)

Main subdivisionsMain subdivisionsAutonomic nervous systemAutonomic nervous system


�� Sympathetic nervous system:Sympathetic nervous system:

� equal pre- and postganglionic fibers

� autonomic ganglia proximally located

� preganglionic fibers – cholinergiccholinergic (ACh)

� postganglionic fibers – adrenergicadrenergic (A, NA)

�� Parasympathetic nervous system:Parasympathetic nervous system:

� longer pre- vs. postganglionic fibers

� autonomic ganglia located nearby targets

or within their walls (intramural ganglia)

� preganglionic fibers – cholinergic (ACh)

� postganglionic fibers – cholinergiccholinergic (ACh)

Structural and neurochemical differencesStructural and neurochemical differencesAutonomic nervous systemAutonomic nervous system


�� parasympathetic reactions:parasympathetic reactions:� generally localized and anabolicanabolic – day-to-day internal processes and behavior� conservation of body energies during rest, preparing us to go to sleep and digestsleep and digest

�� sympathetic reactionssympathetic reactions ::� mass responses – cataboliccatabolic� mobilize body energies

in stressful situations, preparing us for fight, flight or frightfight, flight or fright

Functional considerationsFunctional considerationsAutonomic nervous systemAutonomic nervous system

NB: antagonistic actions of both componentsantagonistic actions of both components

to maintain homeostasis!to maintain homeostasis!


Parasympathetic nervous systemParasympathetic nervous system�� craniosacral division:craniosacral division:

�� cranial region:cranial region:��cranial nerves cranial nerves

III, VII, IX, XIII, VII, IX, X

�� sacral region:sacral region:��spinal cord segments spinal cord segments

S2S2--S4S4

Autonomic nervous systemAutonomic nervous system


Cranial divisionCranial divisionAutonomic nervous systemAutonomic nervous system


Sacral divisionSacral divisionAutonomic nervous systemAutonomic nervous system


�� thoracolumbar division thoracolumbar division –– Th1Th1--L2 segments:L2 segments:�� preganglionic sympathetic axonspreganglionic sympathetic axons

�� intermediolateralintermediolateral columncolumn ofof spinalspinal cordcord

�� paravertebral sympathetic gangliaparavertebral sympathetic ganglia�� sympathetic chain (trunk)sympathetic chain (trunk)

�� prevertebral sympathetic gangliaprevertebral sympathetic ganglia�� celiac ganglionceliac ganglion�� superior mesenteric ganglionsuperior mesenteric ganglion�� inferior mesenteric ganglioninferior mesenteric ganglion

Sympathetic nervous systemSympathetic nervous systemAutonomic nervous systemAutonomic nervous system


�� two symmetrical ganglionated cords:two symmetrical ganglionated cords:

�� cervical part cervical part –– 3 ganglia:3 ganglia:

�� superior cervical ganglionsuperior cervical ganglion – 2.5-3 cm

• jugular nerve

• laryngopharyngeal and superior cardiac branches

• internal and external carotid branches

�� middle cervical ganglion middle cervical ganglion (60%) – 0.7-0.8 cm

• thyroid and middle cardiac branches

�� inferior cervical ganglioninferior cervical ganglion � in 75%

cervicothoracic (stellate) ganglioncervicothoracic (stellate) ganglion – up to 2.8 cm

• inferior cardiac branch

�� thoracic part thoracic part –– 1111--12 segmentally arranged ganglia12 segmentally arranged ganglia�� greater splanchnic nerve greater splanchnic nerve –– ganglion VI-IX

�� lesser splanchnic nerve lesser splanchnic nerve –– ganglion X-XI

�� lowest (renal) splanchnic nerve lowest (renal) splanchnic nerve –– ganglion XII

�� lumbar part lumbar part –– 33--4 segmentally arranged ganglia4 segmentally arranged ganglia� 4 lumbar splanchnic nerveslumbar splanchnic nerves

�� sacralsacral (pelvic)(pelvic) partpart –– 44--55 segmentallysegmentally arrangedarranged gangliaganglia�� sacral splanchnic nervessacral splanchnic nerves

�� terminal terminal ganglion imparganglion impar – anterior to the coccyx

Sympathetic trunkSympathetic trunkAutonomic nervous systemAutonomic nervous system


�� celiac ganglionceliac ganglion ((semilunar semilunar or or solar gangliasolar ganglia ): ): �� largest largest ganglionganglion in the ANSin the ANS� postganglionic sympathetic neurons� paired, with variable position:

� upper part joined with greater splanchnic nerve� lower part receives lesser splanchnic nerve � renal plexus

�� aorticorenal ganglionaorticorenal ganglion�� lower part of celiac ganglion lower part of celiac ganglion � kidney, ureters

�� phrenic ganglionphrenic ganglion� small ganglion on the diaphragm� located at the junction of the right phrenic nerve

�� superior mesenteric ganglionsuperior mesenteric ganglion� close to the origin of the superior mesenteric artery� unpaired, innervates part of the large intestine

�� inferior mesenteric ganglioninferior mesenteric ganglion� several small bodies� close to the origin of the inferior mesenteric artery� innervate part of the large intestine

Prevertebral sympathetic gangliaPrevertebral sympathetic gangliaAutonomic nervous systemAutonomic nervous system


� embedded in the walls of the:� esophagus� stomach� small intestine� colon

� triggered to act when the walls of the hollow organs are stretched by food.

� This local nervous system, referred to as intrinsicintrinsic or enteric nervous systementeric nervous system (ENS), functions independently of the CNS and is influenced by the ANS in a limited way.

� It controls the motility, exocrine and endocrine motility, exocrine and endocrine secretions, local blood flowsecretions, local blood flow, and also modulates immune and inflammatory processesimmune and inflammatory processes of GI tract.


Enteric nervous systemEnteric nervous system

NB: NB: neither sympathetic nor parasympathetic!neither sympathetic nor parasympathetic!


�� The myenteric plexus (of The myenteric plexus (of AuerbachAuerbach) ) primarily controls digestive tract motility [strength & frequency]

�� The submucous plexus (of The submucous plexus (of MeissnerMeissner)) regulates mucosal movements and epithelial cell function [mucosal gland secretion]�� internal submucosal plexus (the true plexus of internal submucosal plexus (the true plexus of MeissnerMeissner))�� external submucosal plexus (the plexus of external submucosal plexus (the plexus of SchabadaschSchabadasch))


Enteric nervous systemEnteric nervous system


Plexus myentericus

Plexus submucosus externus

Plexus submucosus internus


Enteric nervous systemEnteric nervous systemProf. Dr. HeinzProf. Dr. Heinz--Juergen Krammer, Juergen Krammer, University Hospital of Heidelberg at Mannheim, GermanyUniversity Hospital of Heidelberg at Mannheim, Germany



Autonomic transmitters and receptors Autonomic transmitters and receptors

�� Cholinergic transmission:Cholinergic transmission:� release acetylcholineacetylcholine (ACh)

�� two types of acetylcholine receptorstwo types of acetylcholine receptors:�nicotinic receptors (nAChR, also

known as “ionotropic" receptors) �muscarinic receptors (mAChR, also

known as “metabotropic" receptors)


Cholinergic drug effectsCholinergic drug effectsAutonomic nervous systemAutonomic nervous system



Autonomic transmitters and receptors Autonomic transmitters and receptors �� Adrenergic transmission:Adrenergic transmission:

� release noradrenalinenoradrenaline (norepinephrine)

�� two types of adrenergic receptorstwo types of adrenergic receptors:��αα--receptorsreceptors � excitatory responses

• pharmacologically α1- and α2-receptors

��ββ--receptorsreceptors � cause inhibition• pharmacologically β1- and β2-receptors


Adrenergic nerve endingsAdrenergic nerve endingsAutonomic nervous systemAutonomic nervous system


�� aminesamines�� acetylcholine acetylcholine –– excitatory excitatory �� noradrenaline noradrenaline –– inhibitory inhibitory

(norepinephrine)(norepinephrine)�� adrenaline (epinephrine)adrenaline (epinephrine)�� serotonin serotonin

(5(5--Hydroxytriptamine)Hydroxytriptamine)

�� amino acidsamino acids�� GABAGABA

�� purinespurines� ATP

�� gaseous messengersgaseous messengers�� nitric oxidenitric oxide�� carboncarbon monoxidemonoxide

�� NANC neurotransmittersNANC neurotransmitters

spectrum of neurotransmitters:spectrum of neurotransmitters:


Enteric neurotransmittersEnteric neurotransmitters

NB: NB: enteric transmitters = CNS neurotransmittersenteric transmitters = CNS neurotransmitters


““The fate of a nation has often depended on food The fate of a nation has often depended on food or bad digestion of a prime ministeror bad digestion of a prime minister””

VoltaireVoltaireVoltaireVoltaireVoltaireVoltaireVoltaireVoltaire


Is really there a brain in the gut?�� here are some reasons...here are some reasons...


Is really there a brain in the gut?Two brains are better than one, Two brains are better than one, especially if you are hungryespecially if you are hungry!!


�� aggregations (a network) of autonomic nerves and ga nglia:aggregations (a network) of autonomic nerves and ga nglia:� situated in the thoracic, abdominal and pelvic cavities

� innervate the thoracic, abdominal and pelvic viscera

� pass along branches of the arterial blood vessels� composed of sympathetic, parasympathetic, and

sensory fibers

Structural organizationStructural organizationAutonomic plexusesAutonomic plexuses


�� sympathetic innervation sympathetic innervation –– SCGSCG of sympathetic trunk:of sympathetic trunk:� dilator muscle of the iris� tarsal muscle� orbital muscle (of Müller)

�� parasympathetic innervation parasympathetic innervation –– oculomotor (CNIII) oculomotor (CNIII) parasympathetic fibersparasympathetic fibers �� ciliary ganglionciliary ganglion �� short ciliary nervesshort ciliary nerves::� sphincter muscle of the iris � constriction of the pupil� ciliary muscle � eye accommodation (near vision)

Autonomic innervation of the eyeAutonomic innervation of the eyeAutonomic plexusesAutonomic plexuses

} } HornerHorner’’s syndromes syndrome


�� secretory fibers in cranial parasympathetic nervessecretory fibers in cranial parasympathetic nerves

�� parasympathetic innervation:parasympathetic innervation:

� facial nerve:

� pterygopalatine ganglion � lacrimal gland,lacrimal gland,

palatine and nasal glands palatine and nasal glands

� submandibular ganglion �

submandibular and sublingual glandssubmandibular and sublingual glands

� glossopharyngeal nerve:

� pharyngeal plexus, lingual branchestympanic nerve � lesser petrosal nerve � otic ganglion �auriculotemporal nerve � parotid glandparotid gland

�� sympathetic innervation sympathetic innervation –– SCG of sympathetic trunk:SCG of sympathetic trunk:

� deep petrosal nerve � pterygopalatine ganglion �

lacrimal glandlacrimal gland

� external carotid plexus � external carotid nerves �submandibular ganglion � submandibular and sublingual glandssubmandibular and sublingual glands

� external carotid nerves � otic ganglion � parotid glandparotid gland

Autonomic innervation of the salivary glandsAutonomic innervation of the salivary glandsAutonomic plexusesAutonomic plexuses


�� cardiac plexuscardiac plexus – contain both afferent and efferent fibers:

�� superficial (ventral) partsuperficial (ventral) part – cardiac ganglion:� formed by cardiac branch of SCG of sympathetic trunk

and cervical cardiac branches of vagus

� gives branches to the deep part of the plexus, to the right coronary plexus and to the left anterior pulmonary plexus

�� deep (dorsal) part:deep (dorsal) part:� formed by cervical and upper thoracic sympathetic ganglia,

cardiac branches of vagus and recurrent laryngeal nerves

� right half supplies right anterior pulmonary plexus, right atrium and part of left coronary plexus

� left half supplies left atrium,

left anterior pulmonary plexus and

greater part of left coronary plexus

Plexuses in the thoracic cavityPlexuses in the thoracic cavityAutonomic plexusesAutonomic plexuses


�� pulmonary plexuspulmonary plexus – branches from the vagus and sympathicus:� anterior part:

� formed by cardiac branches of the SCG and vagus

� posterior part:� formed by rami of the cardiac branches of the vagus,

from the cardiac plexus and Th2-Th6 sympathetic ganglia� gives branches to the bronchi, pulmonary and bronchial vessels

�� thoracic aortic plexusthoracic aortic plexus – branches to the oesophagus

Plexuses in the thoracic cavityPlexuses in the thoracic cavityAutonomic plexusesAutonomic plexuses


�� coeliac (solar) plexuscoeliac (solar) plexus – the largest autonomic plexus,

located at Th12-L1:

� surrounds the coeliac artery and

root of superior mesenteric artery

� unites the coeliac ganglia

� joined by greater and

lesser splanchnic nerves

�� abdominal aortic plexus abdominal aortic plexus ��

intermesenteric plexusintermesenteric plexus

Primary plexuses in the abdominal cavityPrimary plexuses in the abdominal cavityAutonomic plexusesAutonomic plexuses


�� phrenic plexusphrenic plexus

�� hepatic plexushepatic plexus

�� left gastric plexusleft gastric plexus

�� splenic plexussplenic plexus

�� suprarenal plexussuprarenal plexus

�� renal plexusrenal plexus �� ureteric plexusureteric plexus

�� testicular/ovarian plexustesticular/ovarian plexus

�� superior mesenteric plexussuperior mesenteric plexus

�� inferior mesenteric plexusinferior mesenteric plexus

�� superior hypogastric plexussuperior hypogastric plexus

Secondary plexuses in the abdomenSecondary plexuses in the abdomenAutonomic plexusesAutonomic plexuses


Gastric plexusesGastric plexusesAutonomic plexusesAutonomic plexuses


Autonomic plexusesAutonomic plexuses

Hepatic and splenic plexusesHepatic and splenic plexuses



Suprarenal and renal plexusesSuprarenal and renal plexuses



Superior and inferior mesenteric plexusesSuperior and inferior mesenteric plexuses



Ovarian/testicular plexusesOvarian/testicular plexuses


�� inferior hypogastric (pelvic) plexus:inferior hypogastric (pelvic) plexus:�� hypogastric nerveshypogastric nerves – sympathetic innervation

�� pelvic splanchnic nervespelvic splanchnic nerves –parasympathetic innervation

Primary plexuses in the pelvisPrimary plexuses in the pelvisAutonomic plexusesAutonomic plexuses


�� common (male&female) plexuses:common (male&female) plexuses:�� middle and inferior rectal plexusesmiddle and inferior rectal plexuses�� vesical plexusvesical plexus

�� autonomic plexuses in the male:autonomic plexuses in the male:�� prostatic plexusprostatic plexus�� plexus of the deferent ductplexus of the deferent duct

�� autonomic plexuses in the female:autonomic plexuses in the female:�� uterovaginal plexusuterovaginal plexus�� vaginal nerves vaginal nerves –– parasympatheticparasympathetic

Secondary plexuses in the pelvisSecondary plexuses in the pelvisAutonomic plexusesAutonomic plexuses



Autonomic innervation of male genitalsAutonomic innervation of male genitals�� innervated by both somatic and autonomic nerve fibersinnervated by both somatic and autonomic nerve fibers

�� somatic innervationsomatic innervation :

� pudendal nerve

�� autonomic innervation autonomic innervation – parasympathetic and

sympathetic fibers:� pelvic plexus � cavernous nerve � penis



Autonomic innervation of female genitalsAutonomic innervation of female genitals


Clinical notesClinical notes

� the overall functional status of the body:� vital body processes are autonomic reflex

responses;� many somatic-visceral and visceral

somatic reflexes;� metabolic and mechanical irritations of

autonomic nerve fibers cause different pathologic conditions;

� an appreciation of the nuclei, fiber pathways and resulting reflex deficits from injuries are useful as a diagnostic aid in exploring the diffuse distribution of the autonomic system;

� changes in cutaneous sudomotor and vasomotor reflexes, changes in skin temperature, and increased skin resistance to passage of a minute electric current indicate the involvement of sympathetic nerve fibers;

� a knowledge of dermatomal and peripheral nerve distributions often can provide additional evidence to substantiate both the location and level of a nerve injury.


Thank youThank you……

Autonomic nervous system - Lazarov

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