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Autonomic Nervous SystemAutonomic Nervous System
A. Comparison of somatic and autonomicA. Comparison of somatic and autonomic nervous systemsnervous systems
B. Anatomy of autonomic motor pathwaysB. Anatomy of autonomic motor pathways 1. Overview1. Overview a. Preganglionic neuronsa. Preganglionic neurons b. Autonomic gangliab. Autonomic ganglia c. Postganglionic neuronsc. Postganglionic neurons
C. Physiological effects of the ANSC. Physiological effects of the ANS 1. ANS neurotransmitters1. ANS neurotransmitters 2. Parasympathetic and sympathetic 2. Parasympathetic and sympathetic responsesresponses
The ANS regulates the activities of cardiac The ANS regulates the activities of cardiac muscle, smooth muscle, and glands.muscle, smooth muscle, and glands.
Structurally, the ANS consists of two main Structurally, the ANS consists of two main components:components:
1. visceral afferent neurons1. visceral afferent neurons 2. visceral efferent neurons2. visceral efferent neurons
Functionally, the ANS operates:Functionally, the ANS operates: 1. without conscious control1. without conscious control 2. reflex arc dependent2. reflex arc dependent 3. medulla and hypothalamus override3. medulla and hypothalamus override
Comparison of Somatic and Comparison of Somatic and Autonomic Nervous SystemsAutonomic Nervous Systems
Somatic Somatic AutonomicAutonomic cutaneous receptors chemoreceptorscutaneous receptors chemoreceptors proprioceptors baroreceptorsproprioceptors baroreceptors special senses mechanoreceptorsspecial senses mechanoreceptors
may become conscious unconsciousmay become conscious unconscious
excitatory for skeletal excitatory or inhibitory forexcitatory for skeletal excitatory or inhibitory for muscles cardiac muscle, smoothmuscles cardiac muscle, smooth muscles, and glandsmuscles, and glands
single motor neuron two motor neuronssingle motor neuron two motor neurons
Comparison of Somatic and Comparison of Somatic and Autonomic Efferent PathwaysAutonomic Efferent Pathways
Sympathetic Versus Sympathetic Versus Parasympathetic DivisionsParasympathetic Divisions
Overview of Autonomic Overview of Autonomic PathwaysPathways
Preganglionic neuronPreganglionic neuron
1. first of the two autonomic motor 1. first of the two autonomic motor neuronsneurons2. cell body located in gray matter of 2. cell body located in gray matter of spinal cord or brainspinal cord or brain3. preganglionic axon passes from the 3. preganglionic axon passes from the CNS in a spinal or cranial nerveCNS in a spinal or cranial nerve4. axon terminates in a ganglion4. axon terminates in a ganglion
Overview of Autonomic Overview of Autonomic PathwaysPathways
GanglionGanglion
1. collection of nerve cell bodies located 1. collection of nerve cell bodies located in a specific site outside the CNSin a specific site outside the CNS
2. cell bodies give rise to postganglionic 2. cell bodies give rise to postganglionic neuronsneurons
Overview of Autonomic Overview of Autonomic PathwaysPathways
Postganglionic neuronPostganglionic neuron
1. second of the two autonomic motor 1. second of the two autonomic motor neuronsneurons2. cell body located in ganglion2. cell body located in ganglion3. postganglionic axon passes from the 3. postganglionic axon passes from the ganglion to the effectorganglion to the effector4. peripheral effector is either stimulated 4. peripheral effector is either stimulated or inhibitedor inhibited
Sympathetic Nervous SystemSympathetic Nervous System1. lateral gray horns (T1-L2)1. lateral gray horns (T1-L2)
2. thoracolumbar outflow2. thoracolumbar outflow
3. ganglia3. ganglia
a. sympathetic trunka. sympathetic trunk
(paravertebral)(paravertebral)
b. Prevertebral (collateral)b. Prevertebral (collateral)
4. preganglionic axons short4. preganglionic axons short
5. postganglionic axons long5. postganglionic axons long
Parasympathetic Nervous SystemParasympathetic Nervous System
1. lateral gray horns (S2-4)1. lateral gray horns (S2-4)
2. cranial gray matter2. cranial gray matter
(III, VII, IX, X) (III, VII, IX, X)
3. craniosacral outflow3. craniosacral outflow
4. terminal ganglia4. terminal ganglia
5. preganglionic axons long5. preganglionic axons long
6. postganglionic axons short6. postganglionic axons short
Physiological Effects of ANSPhysiological Effects of ANS
1. dual (duel?) innervation1. dual (duel?) innervation
2. different neurotransmitters2. different neurotransmitters
3. parasympathetic tone3. parasympathetic tone
ANS NeurotransmittersANS Neurotransmitters
CholinergicCholinergic AdrenergicAdrenergic
acetylcholine acetylcholine norepinephrine norepinephrine
all preganglionic neurons all preganglionic neurons most postganglionic most postganglionic all postganglionic parasympathetic neurons sympathetic neuronsall postganglionic parasympathetic neurons sympathetic neurons few postganglionic sympathetic neuronsfew postganglionic sympathetic neurons
acetylcholinesterase acetylcholinesterase catechol-O-methyl catechol-O-methyl transferasetransferase
monoamine oxidasemonoamine oxidase
Neurotransmitters and Receptors of the Neurotransmitters and Receptors of the Autonomic Nervous SystemAutonomic Nervous System
Sympathetic SystemSympathetic System
1. energy expenditure system1. energy expenditure system
2. fight-or-flight response2. fight-or-flight response
3. dominates parasympathetic NS3. dominates parasympathetic NS
4. effects4. effects
Parasympathetic SystemParasympathetic System
1. energy conservation-restoration 1. energy conservation-restoration systemsystem
2. rest-and-recovery2. rest-and-recovery
3. dominates sympathetic NS3. dominates sympathetic NS
4. SLUD4. SLUD