Download autonomic nervous system

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
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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
SYSTEM
EPINEPHRINE 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
NICOTINIC
MUSCARINIC
• ANDRENERGIC
ALPHA 1
ALPHA 2
BETA 1
BETA 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
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ALPHA
BETA
ALL ARE G LINKED RECEPTORS
NON CHANNEL LINKED RECEPTORS
NOREPINEPHRINE
• BINDS WITH
–
–
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–
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
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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
• PARASYMPATHETIC
• DILATION OF PUPIL • CONSTRICTION OF
PUPIL
• CONTRACTION OF
RADIAL MUSCLES
• CONTRACTION OF
CIRCULAR
MUSCLES
CILIARY MUSCLE
• SYMPATHETIC
• SLIGHT
RELAXATION
• PARASYMPATHETIC
• CONTRACTION
• ACCOMODATES FOR
NEAR VISION
URINARY BLADDER
• SYMPATHETIC
• RELAXATION
• PARASYMPATHETIC
• CONTRACTION
BLOOD VESSELS
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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
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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
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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
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PLANT ALKALOID (NIGHTSHADE)
PUPIL DILATION
FAST HEART RATE
REDUCES SECRETION OF EXOCRINE GLANDS
RELAXES SMOOTH MUSCLE
• ANTICHOLINERGIC
• OPPOSES ACTION OF ACETYLCHOLINE