INTRODUCTION TO THE AUTONOMIC NERVOUS SYSTEM STEVEN J. ZEHREN, PH.D.
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Transcript of INTRODUCTION TO THE AUTONOMIC NERVOUS SYSTEM STEVEN J. ZEHREN, PH.D.
INTRODUCTION TO THE AUTONOMIC NERVOUS SYSTEM
STEVEN J. ZEHREN, PH.D.
GENERAL REMARKSABOUT THE NERVOUS SYSTEM
STRUCTURAL DIVISIONS: CNS AND PNS
CENTRAL AND PERIPHERAL NERVOUS SYSTEMS
FUNCTIONAL DIVISIONS:SOMATIC AND VISCERAL NERVOUS SYSTEMS
SOMATIC & VISCERAL NERVOUS SYSTEMS
AUTONOMIC NERVOUS SYSTEM (= VISCERAL MOTOR SYSTEM)
CLASSIFICATION OF FIBER TYPES (FUNCTIONAL COMPONENTS) IN CRANIAL* AND SPINAL NERVES
Afferent(sensory)
Somatic(outer)
Visceral(inner)
General(wide distribution)
Special(restricted distribution)
From skin — pain, temp., touchFrom skeletal muscles & tendons,ligs. of joints -- proprioception
From retina – sightFrom inner ear – hearing & equilibrium
General From internal organs – visceral reflexes,fullness of hollow organs, pain
From taste buds – tasteFrom olfactory mucosa -- smell
Special
Efferent(motor)
Somatic
Visceral
General
Special
General
Special
To skeletal muscles not derived from pharyngeal arches
XXX – This category does not exist
To smooth muscle, cardiac muscle & glands
To skeletal muscles derived from pharyngeal arches
*Special components occur only in certain cranial nerves.
STRUCTURE OF A TYPICAL SPINAL NERVE (T1 – L2)
. TYPICAL SPINAL NERVE ( T1 – L2)
TWO TYPES OF GANGLIA:SENSORY & AUTONOMIC
COMPARISON OF SYMPATHETIC & PARASYMPATHETIC SYSTEMS
SIMILARITIES
2 NEURON CHAIN
INNERVATION OF THE SUPRARENAL MEDULLA
NEURON #1 LIES IN CNS
NEURON #2 LIES IN A GANGLION
GANGLION
GANGLION
NEUROTRANSMITTER RELEASED AT GANGLION IS ACETYLCHOLINE
GANGLION (ACH)
GANGLION (ACH)
DIFFERENCES
THORACOLUMBAR (SYMPATHETIC) VS. CRANIOSACRAL (PARASYMPATHETIC) OUTFLOW
Lateral horn of gray matter(intermediolateral nucleus)White matter
Dorsal (posterior) hornof gray matter
Ventral (anterior) hornof gray matter
Ventral median fissure
T2 T8C5
L 1 L2 S2 S3
LENGTH OF PRESYNAPTIC& POSTSYNAPTIC FIBERS
NEUROTRANSMITTER RELEASED AT EFFECTOR ORGAN
USUALLYNOREPINEPHRINE
ACH
WHEN AN ORGAN RECEIVES A DUAL INNERVATION, THE SYSTEMS USUALLY HAVE ANTAGONISTIC PHYSIOLOGICAL EFFECTSAGGRESSIVE
VEGETATIVE
INCREASE HEART RATE
DECREASEHEART RATE
AREAS OF DISTRIBUTION OF SYMPATHETIC VS. PARASYMPATHETIC FIBERS
Sympathetic system reaches virtually all parts of the bodyvirtually all parts of the body(with the rare exception of such avascular tissues as cartilage and nails).(with the rare exception of such avascular tissues as cartilage and nails).
Parasympathetic system distributes only to the head and neck, visceral cavities of the trunk,and the erectile tissues of the external genitalia (with the exception of the latter, it does notreach the body wall or limbs).
PARASYMPATHETIC SYSTEM
CRANIAL OUTFLOW(TO HEAD, NECK, THORAX, & UPPER ABDOMEN)
PARASYMPATHETIC SYSTEM
L. colic flexure
PARASYMPATHETIC GANGLIA IN HEADPARASYMPATHETIC GANGLIA IN HEAD
III --- III --- CCILIARY GANGLIONILIARY GANGLION
IX --- IX --- OOTIC GANGLIONTIC GANGLION
VII --- VII --- PPTERYGOPALATINE GANGLIONTERYGOPALATINE GANGLION
---- ---- SSUBMANDIBULAR GANGLIONUBMANDIBULAR GANGLION X --- UNAMED GANGLIA IN NECK, THORAX & ABDOMENX --- UNAMED GANGLIA IN NECK, THORAX & ABDOMEN
“ “COPS”COPS”
SACRAL OUTFLOW(TO LOWER ABDOMEN & PELVIS)
PARASYMPATHETIC SYSTEM
Pelvic splanchnic nn
SYMPATHETIC SYSTEM
GENERAL SCHEME OFSYMPATHETIC NERVOUS SYSTEM
Splanchnic n.
Rami communicantes
.
GRAY & WHITERAMI COMMUNICANTESCONNECT TO SPINAL NERVEST1 - L2
(T1 – L2)
WHITE RAMI = PRESYNAPTIC FIBERSGRAY RAMI = POSTSYNAPTIC FIBERS
.ONLY GRAY RAMI COMMUNICANTESCONNECT TO SPINAL NERVESABOVE T1 AND BELOW L2
(above T1 or below L2)
Gray ramus comunicans
Courses taken by presynapticsympathetic fibers within thesympathetic trunks:
1. Ascend and then synapse
2. Synapse at level of entry
3. Descend and then synapse
4. Pass through sympthetic trunk without synapsing to enter a splanchnic nerve, and then synapse in a prevertebral ganglion
_ _ _ _ _ _ Presynaptic sympathetic
_________ Postsynaptic sympathetic
Splanchnic n.
Prevertebral ganglion.
Thoracic cardiac n.
SYMPATHETIC INNERVATION (TO PERIPHERY)
SYMPATHETIC INNERVATION TO PERIPHERY (BODY WALL & EXTREMITIES)
PERIPHERAL DISTRIBUTION OF SYMPATHETICS BETWEEN T1 & L2
SYMPATHETIC INNERVATION (TO HEAD)
Internal carotid n.
Superior cervical ganglion
Gray rami communicantes
External carotid a. & plexus
Middle cervical ganglion
Cervicothoracic (stellate) ganglionAnsa subclavia
Vertebral ganglionVertebral a. & plexus
SYMPATHETIC SUPPLY TO HEADSYMPATHETIC SUPPLY TO HEAD
SYMPATHETIC INNERVATION (TO THORACIC VISCERA)
TO VISCERA(THORACIC)
TO VISCERA (THORACIC)
Paravertebralganglion
Thoracic cord segments T1-T5
Sympathetic trunk
Pulmonary plexus
Sympathetic fibers
SYMPATHETIC SUPPLY TO LUNGS
RED
SYMPATHETIC SUPPLY TO HEART
SYMPATHETIC INNERVATION (TO ABDOMINAL & PELVIC VISCERA)
Prevertebralganglion
TO VISCERA(ABDOMINAL & PELVIC)
TO VISCERA(ABDOMINAL& PELVIC)
SPLANCHNIC N.(THORACIC,LUMBAR, &SACRAL)
SYMPATHETIC SUPPLY TO ABDOMINAL & PELVIC VISCERA
Greater and lesserthoracic splanchnic nn.
Aorticorenal ganglion
Least thoracic splanchnic n.
Renal a. and plexus
2nd and 3rd lumbar splanchnic nn.
4th lumbar splancnic n.
Celiac ganglia
Superior mesenteric ganglion
Inferior mesenteric ganglion
Superior hypogastric plexus
Hypogastric nn.(to inferior hypogastric plexus)
1st lumbar splanchnic n.
END OF LECTURE