AUTONOMIC NERVOUS SYSTEM

PART OF EFFERENT DIVISION OF PERIPHERAL NERVOUS

SYSTEM

ANATOMY OF THE ANS

• PRESYMPATHETIC NEURON -- CELL BODY IN CNS

• POSTSYMPATHETIC NEURON --CELL BODY IN PERIPHERAL NERVOUS SYSTEM

• AUTONOMIC PLEXUS

PARASYMPATHETIC VS SYMPATHETIC DIVISIONS

EMBRYONIC DEVELOPMENT

SYMPATHETIC DIVISION• LOCATED IN LATERAL HORNS IN GRAY MATTER• T-1 TO L-2• THORACOLUMBAR• LEAVES SPINAL CORD THROUGH VENTRAL

ROOMS• ENTER VENTRAL RAMI OF SPINAL NERVES• ENTER SYMPATHETIC CHAIN GANGLIA• SYMPATHETIC TRUNKS

SYMPATHETIC NERVOUS SYSTEM

• RAMI COMMUNICANTES– WHITE– GRAY

SYMPATHETIC CHAIN GANGLIA

• PARAVERTERBRAL GANGLIA

• SYMPATHETIC TRUNK

• WHITE RAMI COMMUNICANTES– MYELINATED– CARRY IMPULSES FROM SPINAL NERVE

TO CHAIN GANGLIA

• GRAY RAMI COMMUNICANTES

FATE OF PREGANGLIONIC NEURONS UPON ENTERING

SYMPATHETIC CHAIN GANGLIA

MAY SYNAPSE WITH POSTGANGLIONIC IN

SYMPATHETIC CHAIN GANGLIA AT THE SAME LEVEL

• RETURN TO SPINAL NERVE TO INNERVATE EFFECTORS. GRAY RAMI COMMUNICANTES ARE FORMED BY UNMYELINATED POSTGANGLIONIC AXONS AS THEY PASS FROM CHANIN GANGLIA TO SPINAL NERVES

MAY TRAVEL UP OR DOWN WITHIN SYMPATHETIC TRUNKS

BEFORE SYNAPSING WITH POSTGANGLIONIC NEURONS THAT SUPPLY EFFECTORS IN

SKIN, HEAD, OR THORAX

MAY PASS THROUGH SYMPATHETIC CHAIN GANGLIA

WITHOUT SYNAPSING AND SYNAPSE WITH

POSTGANGLIONIC NEURONS IN COLLATERA GANGLIA

• SUPPLY VISCERA OF ABDOMINOPELVIC CAVITY

PARASYMPATHETIC SYSTEM

PARASYMPATHETIC DIVISION• PREGANGLIONIC NEURON CELL BODIES LOCATED

IN BRAIN NUCLEI OR IN LATERAL PORTIONS OF GRAY MATTER IN SPINAL CORD (S-2 THROUGH S-4)

• FIBERS DO NOT TRAVEL THROUGH RAMI OF SPINAL NERVE

• DO NOT INNERVATE SWEAT GLANDS, ARRECTOR PILI, AND CUTANEOUS BLOOD VESSEL

• MOST BLOOD VESSELS ARE NOT INNERVATED BY PARASYMPATHETIC

PREGANGLIONIC PARASYMPATHETIC AXONS

IN CRANIAL NERVES• III,VII,IX AND X

• SYNAPSE WITH POSTGANGLIONIC NEURONS IN GANGLIA

• NEAR STRUCTURES INNERVATED

SACRAL PREGANGLIONIC PARASYMPATHETIC AXONS • LEAVE VENTRAL ROOTS OF SPINAL

NERVES

• FORM A PELVIC NERVE THAT SUPPLIES VISCERA OF PELVIC CAVITY

ANATOMICAL DIFFERENCES BETWEEN THE DIVISIONS

• LOCATION OF PREGANGLIONIC NEURON CELL BODIES

• FIBER LENGTH

LOCATION OF PREGANGLIONIC NEURON CELL BODIES

• SYMPATHETIC --- LATERAL HORNS OF SPINAL CORD GRAY MATTER FROM T-1 TO L-2

• PARASYMPATHETIC --- BRAIN STEM AND LATERAL HRONS OF SPINAL CORD GRAY MATTER FROM S-1 THROUGH S-4

FIBER LENGTH

• SHORT SYMPATHETIC PREGANGLIONIC AXONS-LONG SYMPATHETIC POSTGANGLIONIC AXONS

• LONG PARASYMPATHETIC PREGANGLIONIC AXONS-SHORT PARASYMPATHETIC POSTGANGLIONIC AXONS

NEUROTRANSMITTERS OF THE AUTONOMIC NERVOUS

SYSTEMEPINEPHRINE VS

NOREPINEPHRINE

SITES FOR RELEASE OF ACETYLCHOLINE IN THE

PERIPHERAL NERVOUS SYSTEM

• NEUROMUSCULAR JUNCTIONS

• ALL PREGANGLIONIC NEURONS IN ANS

• ALL PARASYMPATHETIC POSTGANGLIONIC NEURONS

• SYMPATHETIC POSTGANGLIONIC NEURONS INNERVATING SWEAT GLANDS

SITES FOR RELEASE OF NOREPINEPHRINE IN THE

PERIPHERAL NERVOUS SYSTEM

• MOST SYMPATHETIC POSTGANGLIONIC NEURONS

• ADRENAL MEDULLA

RECEPTORS OF THE AUTONOMIC NERVOUS

SYSTEM• CHOLINERGIC

NICOTINICMUSCARINIC

• ANDRENERGICALPHA 1ALPHA 2BETA 1BETA 2

NICOTINIC RECEPTORS

• NICOTINE MIMICS EFFECTS• PRESENT ON POSTGANGLIONIC NEURONS IN GANGLI OF

THE ANS• ALSO ON SKELETAL MUSCLE AT NEUROMUSCULAR

JUNCTIONS• CHANNEL LINKED RECEPTORS• BLOCKED BY TETRAETHYLAMMONIUM--IN AUTONOMIC

GANGLIA• BLOCKED BY CURARE--AT NEUROMUSCULAR JUNCTION

MUSCARINIC RECEPTORS

• MUSCARINE MIMICS EFFECTS

• ON EFFECTORS SUPPLIED BY PARASYMPATHETIC POSTGANGLIONIC RECEPTORS

• G PROTEIN LINKED RECEPTORS

• BLOCKED BY ATROPINE

ANDRENERGIC RECEPTORS

• ALPHA

• BETA

• ALL ARE G LINKED RECEPTORS

• NON CHANNEL LINKED RECEPTORS

NOREPINEPHRINE

• BINDS WITH– ALPHA 1-- EFFECTIVELY– ALPHA 2 -- EFFECTIVELY– BETA 1-- EFFECTIVELY– BETA 2 --WEAKLY IF AT ALL

EPINEPHRINE

• BINDS EFFECTIVELY WITH– ALPHA 1-- EFFECTIVELY– ALPHA 2 -- EFFECTIVELY– BETA 1-- EFFECTIVELY– BETA 2 --EFFECTIVELY

ALPHA 1 RECEPTORS

• MOST COMMON ALPHA RECEPTOR

• ACTIVATES G PROTEINS

• G PROTEINS ACTIVATE ENZYMES

ALPHA 2 RECEPTORS

• LESS COMMON THAN ALPHA 1

• ACTIVATES INHIBITORY G PROTEINS

• REDUCE THE FORMATION OF cyclic AMP

BETA 1 RECEPTORS

• HEART AND KIDNEYS

• ACTIVATES G PROTEINS

• STIMULATES PRODUCTION OF cyclic AMP

BETA 2 RECEPTOR

• MOST COMMON BETA RECEPTOR

• ACTIVATES STIMULATORY G PROTEINS

IMPORTANCE OF DIFFERENT RECEPTORS

• AT LEAST PARTIALLY RESPONSIBLE FOR DIFFENCE IN ACTIVITY OF EPINEPHRINE AND NOREPINEPHRINE

FUNCTIONS OF THE AUTONOMIC NERVOUS SYSTEM

• DUAL INNERVATION

• FREQUENTLY (BUT NOT ALWAYS) HAVE OPPOSITE ACTIONS

• MOSTS ORGANS ARE PREDOMINANTLY CONTROLLED BY ONE DIVISION OR THE OTHER

PARASYMPATHETIC

• HOUSEKEEPING FUNCTIONS

• MAINTAINING BODY FUNCTIONS UNDER CALM CONDITIONS

• INDIVIDUAL ACTIVATION OF INDIVIDUAL ORGANS

SYMPATHETIC

• FIGHT OR FLIGHT

• HANDLES EMERGENCIES

• WIDESPREAD ACTIVATION

EXAMPLES OF ORGANS INNERVATED BY ANS

• HEART• BRONCHIOLES• BRONCHIAL GLANDS• IRIS OF EYE• CILIARY MUSCLE• SWEAT GLANDS• URINARY BLADDER• BLOOD VESSELS

HEART

• SYMPATHETIC• INCREASE RATE

OF CONTRACTION

• PARASYMPATHETIC• DECREASE RATE OF

CONTRACTION

BRONCHIOLES

• SYMPATHETIC• DILATION

• PARASYMPATHETIC• CONSTRICTION

BRONCHIAL GLANDS

• SYMPATHETIC• POSSIBLE

INHIBITION OF SECERETION

• PARASYMPATHETIC• STIMULATION OF

SECRETION

IRIS OF EYE

• SYMPATHETIC • DILATION OF

PUPIL • CONTRACTION OF

RADIAL MUSCLES

• PARASYMPATHETIC• CONSTRICTION OF

PUPIL• CONTRACTION OF

CIRCULAR MUSCLES

CILIARY MUSCLE

• SYMPATHETIC• SLIGHT

RELAXATION

• PARASYMPATHETIC• CONTRACTION• ACCOMODATES FOR

NEAR VISION

URINARY BLADDER

• SYMPATHETIC• RELAXATION

• PARASYMPATHETIC• CONTRACTION

BLOOD VESSELS

• SYMPATHETIC• CONSTRICTION • SKIN• SALIVARY GLANDS• ABDOMINAL

VISCERA• EXTERNAL

GENITALIA

• PARASYMPATHETIC• EXTERNAL

GENITALIA

ADRENAL MEDULLA

• SYMPATHETIC• STIMULATION OF

SECRETION

• PARASYMPATHETIC• NO EFFECT

LIVER

• SYMPATHETIC• INCREASED

RELEASE OF GLUCOSE

• PARASYMPATHETIC• NO EFFECT

SWEAT GLANDS

• SYMPATHETIC• STIMULATION OF

SECRETION

• PARASYMPATHETIC• NO EFFECT

THE AUTONOMIC NERVOUS SYSTEM AND SENSORY INPUTS

• ACTIVITIES OF ANS ARE MOTOR ONLY

• NEED INPUT FROM SENSORY SYSTEM

• TO MONITOR BODY FUNCTIONS AS A WHOLE AND INDIVIDUAL ORGANS

• ENTEROCEPTIVE RECEPTORS

• BELOW CONSCIOUS LEVEL

CONTROL OF THE AUTONOMIC NERVOUS

SYSTEM

• GENERALLY BELOW OUR CONSCIOUS CONTROL

• UNDER CERTAIN CIRCUMSTANCES VOLUNTARY CONTROL IS POSSIBLE– DUE TO CONNECTIONS BETWEEN ANS AND CNS– PRIMARILY IN BRAIN STEM AND SPINAL CORD

BIOFEEDBACK MECHANISMS

• EXERCISES MODIFY BODY FUNCTIONS

• VISUALIZATION

• RECITATION

MEDITATION AND THE ANS

• YOGA

• MEDITATION

• BREATHING THERAPY

• INHIBITS SYMPATHETIC NERVOUS SYSTEM

DRUGS AND THE ANS

• MEDICINAL

• SUBSTANCE ABUSE

MEDICINAL DRUGS

• SYMPATHOMIMETIC

• SYMPATHOLYTIC

• PARA

SYMPATHOMIMETIC DRUGS

• ANDRENERGIC DRUGS THAT STIMULATE SYMPATHETIC NERVOUS SYSTEM

• EITHER NATURAL OR MAN MADE• EPINEPRINE• EPINEPHRINE• ISOPROTERENOL• DOPAMINE• EPHEDRINE• TERBUTALINE• PHENYLEPHRINE

EPINEPHRINE

• ALPHA AND BETA RECEPTORS

• ANAPHYLACTIC SHOCK

• ASTHMA

• BRONCHOSPASM

NOREPINEPHRINE

• ALPHA AND BETA RECEPTORS

• ELEVATE BLOOD PRESSURE IN HYPOTENSION

• ADMINISTERED INTROVENOUSLY

• LIMITED USES DUE TO SIDE EFFECTS

ISOPROTERENOL

• LIMITED USE DUE TO POOR ABSORPTION IN GI TRACT

• ADMINISTERED SUBLINGUALLY OR AS NASAL SPRAY FOR SOME CARDIAC ARRYTHMIAS

DOPAMIME

• PRECURSOR FOR NOREPINEPHRINE• LOW DOSAGES ACTIVATES BETA

RECEPTORS• HIGHER DOSAGES ACTIVATES

ALPHA RECEPTORS• USED FOR HYPOTENSION AND

RESISTANT CONGESTIVE HEART FAILURE

EPHEDRINE, TERBUTALINE, AND PHENYLEPHRINE

• EPHEDRINE– SIMILAR TO EPINEPHRINE– SLOWER TO BEGIN WORKING– LAST LONGER

• TERBUTALINE– BETA RECEPTOR– LITTLE CARDIAC STIMULATION

• PHENYLEPHRINE– CAUSES NASAL CONSTRICTION– USED IN COLD MEDICATIONS

SYMPATHOLYTIC

• ANDRENERGIC BLOCKING DRUGS

• REDUCE OR BLOCK EFFECTS OF SYMPATHETIC NERVOUS SYSTEM

• ALPHA BLOCKING AGENTS

• BETA BLOCKING AGENTS

ALPHA BLOCKING AGENTS

• LIMITED USES MEDICALLY– RAYNAUD’S DISEASE– AFTER FROSTBITE– ATERIOSCLEROSIS OBLITERANS

• VASODILATOR

• TALOZOLINE

• PHENTOLAMINE

BETA BLOCKING AGENT

• PRODUCES EFFECTS IN CARDIOVASCULAR SYSTEM

• REDUCE HEART RATE• REDUCE MYOCARDIAL CONTRACTION• REDUCED STROKE VOLUME• REDUCES CARDIAC OUTPUT AND OXYGEN

CONSUMPTION• LOWERS BLOOD PRESSURE OVER LONG

HAUL• PROPANOLOL

PARASYMPATHOMIMETIC

• CHOLINERGIC DRUGS

• VASODILATES PERIPHERAL BLOOD VESSELS

• CHOINE ESTERS

• CHOLINERGIC ALKALOIDS

• ANTICHOLINESTERASES

CHOLINE ESTERS

• BETHANECHOL

• INCREASES MOTILITY OF BOWEL AND BLADDER

CHOLINERGIC ESTERS

• PILOCARPINE

• CONSTRICTS PUPIL IN TREATMENT OF GLAUCOMA

ANTICHOLINESTERASES

• PHYSOSTIGIMINE– REVERSES EFFECTS OF ATROPINE

POISONING

• EDROPHONIUM CHLORIDE– MYASTHENIA GRAVIS DIAGNOSIS

• BLOCK ENZYME

• PROLONG ACTION OF AC h

PARASYMPATHOLYTIC DRUGS

• ATROPINE– PLANT ALKALOID (NIGHTSHADE)

– PUPIL DILATION

– FAST HEART RATE

– REDUCES SECRETION OF EXOCRINE GLANDS

– RELAXES SMOOTH MUSCLE

• ANTICHOLINERGIC• OPPOSES ACTION OF ACETYLCHOLINE