Introduction to Physiology: The Cell and General Physiology

1
Physiologic Anatomy of the Sympathetic Nervous
System
Axons travel to ganglionic neuron via 1 of 3
paths
Visceral motor neuron (preganglionic) located in
the (intermedio)lateral horn of the spinal cord
from T-1 to L-2.
1. enter the sympathetic chain via the white
ramus and terminate there or ascend or descend a
few segments before terminating
2. enter via the white ramus and exit via a
splanchnic nerve and terminate in a prevertebral
(collateral) ganglion
3. Enter via the white ramus and exit via a
splanchnic nerve and terminate in the adrenal
medulla
Figure 60-2 Guyton Hall
2
Sympathetic Nervous System
Figure 60-1Guyton Hall
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Sympathetic Organization
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4
Sympathetic Chain
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Figure 16.4a
5
Collateral Ganglia
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6
Adrenal Gland
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Sympathetic Distribution
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Parasympathetic Nervous System
Figure 60-3 Guyton Hall
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Parasympathetic Organization
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10
Parasympathetic Distribution
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Neurotransmitters
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Receptors of the Autonomic Nervous System
adrenergic receptors
sympathetic
preganglionic neuron
postganglionic neuron
parasympathetic
nicotinic receptors
muscarinic receptors
13
Pharmacology of the Sympathetic Nervous System

• adrenergic or sympathomimetic drugs act like
  norepi and epi
• these drugs have an effect which is much more
  prolonged than that of either norepi or epi
• isoproterenol stimulates both beta1 and beta2
  receptors (e.g. increases heart rate)
• albuterol stimulates only beta2 receptors (e.g.
  bronchodilation)
• some drugs act indirectly by increasing the
  release of norepi from its storage terminals
• amphetamine

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Pharmacology of the Sympathetic Nervous System

• Example - drugs that block the effect of norepi
  and epi
• beta blockers
• beta1 - metoprolol

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Pharmacology of the Parasympathetic Nervous System

• parasympathomimetic drugs
• nicotine
• activates nicotinic receptors
• cholinesterase inhibitors
• neostigmine
• potentiates the effect of acetylcholine
• antimuscarinic drugs
• atropine
• blocks the effect of acetylcholine on effector
  cells