Human Anatomy

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Human Anatomy

• The Autonomic Nervous System
• ANS

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ANS

• Regulates various physiological processes
  unconsciously, for instance
• Cardiovascular
• Respiration
• Digestion
• Body temperature
• Excretion

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2 Subdivisions of the ANS

• Sympathetic NS
• fight or flight
• Parasympathetic NS
• rest and repose

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Anatomy of ANS

• Consists of only 2 neurons
• Preganglionic neuron (1)
• Ganglionic neuron (2)
• The ganglion is a structure where the axon of the
  preganglionic neuron synapses (release of
  neurotransmitter) with the ganglionic neuron
  (dendrite or cell body)
• The axon of the ganglion synapses with the target
  cell or organ.

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Anatomical differences between sympathetic and
parasympathetic
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Anatomy of the ANS

• Differences between sympathetic and
  parasympathetic are
• Location of preganglionic (1) cell body
• Location of the ganglia
• Neurotransmitters released at synapses
• Effects on target organs

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1. Sympathetic Anatomy

• Once again, just 2 cells
• Preganglion (1) cell body in gray matter of
  spinal cord ---- levels T1 L2
• Thoracolumbar system

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Sympathetic Anatomy
Thoracolumbar
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Sympathetic Anatomy

• Synapse of preganglionic (1) with ganglionic
  (2) neurons happens in the ganglion
• 3 pair of cervical ganglia
• 3 abdominal ganglia
• All of the above ganglia are referred to as
  paravertebral ganglia
• Neurotransmitter is acetylcholine (ACh)

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Sympathetic Anatomy
Thoracolumbar
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Sympathetic Ganglia

• Paravertebral ganglia
• Cervical
• Superior (LR)
• Middle (LR)
• Inferior (LR)
• Abdominal
• Celiac
• Superior mesenteric
• Inferior mesenteric

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Sympathetic Anatomy
Thoracolumbar
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Sympathetic Anatomy

• Ganglionic (2) axons are relatively long
• Synapse at target cell or organ
• Neurotransmitter is norepinephrine (NE)

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Sympathetic Anatomy
Thoracolumbar
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2. Parasympathetic Anatomy

• Once again, just 2 cells
• Preganglionic (1) cell body in either
• Brainstem
• Spinal cord ---- S2 S4
• Craniosacral system

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Parasympathetic Anatomy
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Parasympathetic Anatomy

• Synapse of preganglionic with ganglionic neurons
  happens in the ganglion
• Ganglia are located on the target organs

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Parasympathetic Anatomy
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Parasympathetic Anatomy

• Ganglionic axons are relatively short
• Synapse at target cell or organ
• Neurotransmitter is acetylcholine (ACh)

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Anatomical differences between sympathetic and
parasympathetic
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Parasympathetic Anatomy
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Summary

• Sympathetic
• Thoracolumbar
• Paravertebral ganglia
• ACh then NE

• Parasympathetic
• Craniosacral
• Ganglia at target
• 3. ACh and ACh

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Biological Effects

• Most organs have dual innervation
• CV
• S increase heart rate, force of ventricle
  contraction, increase blood pressure by
  constricting smooth muscles of arteries
• P -- opposite

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Biological Effects

• Respiration
• S dilation of bronchiole smooth muscle which
  increases diameter
• P opposite
• Digestion
• S decreases activity of organs and glands
• P -- opposite

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Biological Effects

• Vision
• S dilation of pupil
• P constriction of pupil
• Reproduction
• S causes ejaculation in males
• P sexual arousal (erection) in both sexes