Autonomic

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Autonomic Nervous System
Dr. Sama-ul-Haque
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Objectives

• Define autonomic nervous system.
• Describe sympathetic and parasympathetic nervous
  system.
• Enumerate the functions of sympathetic and
  parasympathetic nervous system.

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The Autonomic Nervous System

• ANS is the subdivision of the peripheral nervous
  system that regulates body activities that are
  generally not under conscious control
• Visceral motor innervates non-skeletal
  (non-somatic) muscles
• Composed of a special group of neurons serving
• Cardiac muscle (the heart)
• Smooth muscle (walls of viscera and blood
  vessels)
• Internal organs
• Skin

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• Basic anatomical difference between the motor
  pathways of the voluntary somatic nervous system
  (to skeletal muscles) and those of the autonomic
  nervous system
• Somatic division
• Cell bodies of motor neurons reside in CNS (brain
  or spinal cord)
• Their axons (as nerves) extend all the way to
  their skeletal muscles.
• Autonomic system chains of two motor neurons
• 1st preganglionic neuron (in brain or cord)
• 2nd gangionic neuron (cell body in ganglion
  outside CNS)

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• Axon of 1st (preganglionic) neuron leaves CNS to
  synapse with the 2nd (ganglionic) neuron.
• Axon of 2nd (ganglionic) neuron extends to the
  organ it serves

Diagram contrasts somatic (lower) and autonomic
autonomic
this dorsal root ganglion is sensory
somatic
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Divisions of the autonomic nervous system

• Parasympathetic division
• Sympathetic division
• Serve most of the same organs but cause opposing
  or antagonistic effects

Parasympathetic routine maintenance rest
digest Sympathetic mobilization increased
metabolism fight, flight or fright
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Where they come from
Sympathetic Thoracolumbar T1 to L2
Parasympathetic Craniosacral
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Paravertebral Ganglionic chain or Sympathetic
Trunk
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Paravertebral Ganglionic chain
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Spinal Nerve
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Sympathetic nerve
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Sympathetic Nervous system
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Parasympathetic Nervous system
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Functions of Sympathetic Nervous System

• Increased Heart Rate
• Increased Blood Pressure
• Pupil Dilation
• Decreased Urination
• Increased Sweating
• Bronchial Dilation
• Decreased Salivation

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Functions of Parasympathetic Nervous System

• Decreased Heart Rate
• Decreased Blood Pressure
• Pupil Constriction
• Increased Urination
• Decreased Sweating
• Bronchial Constriction
• Increased Salivation

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Thank You