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Autonomic Nervous System

  1. Development of ANS
    • Neural crest derived neurons migrate from developing DRG to:
    • 1. Paravertebral (sympathetic chain)
    • 2. Prevertebral ganglia
    • 3. Medulla of developing adrenals
    • 4. Developing gut (enteric NS)
  2. Sympathetic Preganglionic Neurons
    • Lateral horn of spinal cord (T1 - L2/3)
    • 1. synapse in paravertebral ganglia
    • IML cell column of spinal cord (T5 - T12)
    • 2. travel via splanchnic n. to prevertebral ganglia

    Cholinergic
  3. Sympathetic Postganglionic Neurons
    • Paravertebral (sympathetic chain)
    • Prevertebral (collateral ganglia)
    • Fibers terminate on effector organs

    • Adrenergic
    • (except sweat glands)
  4. Splanchnic Nerves
    • Carry sympathetic preganglionic axons from anterior roots to prevertebral ganglia
    • Cell bodies of splanchnic nerves come from:
    • greater splanchnic n. = T5-T9 IML
    • Lesser splanchnic n. = T10-T11 IML
    • Least splanchnic n. = T11-T12 IML
  5. Sympathetics in DRG
    • Somatic neurons
    • Visceral afferent neurons
  6. Sympathetics in White Communicating Rami
    Myelinated Pregnaglionic axons from ant. rami
  7. Sympathetics in Gray Communicating Rami
    Unmyelinated Postganglionic axons from paravertebral (sympathetic) ganglia
  8. Superior cervical ganglia
    • Sympathetic ganglia in the head
    • Postganglionic axons travel along blood vessels to targets in head

    Injury to neurons in this pathway can cause horner's syndrome
  9. Parasympathetic Preganglionic Neurons
    • Brainstem nuclei
    • Sacral spinal cord

    Cholinergic
  10. Parasympathetic Postganglionic Neurons
    In walls of viscera

    Cholinergic
  11. Enteric Nervous System
    • Neural crest cells migrate to developing gut wall and form 2 plexuses
    • 1. Submucosal (Meissner's plexus)
    • 2. Myenteric (Auerbach's plexus)

    Can work in absense of input from the brain / spinal cord
  12. Meissner's Plexus (submucosal)
    • Enteric NS plexus
    • 1. regulates secretion by glandular epithelium
    • 2. regulates motility of muscularis mucosa
    • 3. sensory signal of material in lumen
  13. Auerbach's Plexus (myenteric)
    • Enteric NS plexus
    • 1. regulates peristalsis
    • 2. regulates sphincters
  14. Peristaltic Reflex
    • 1. Bolus distorts mucosa
    • 2. Enterochromaffin cells release seratonin (5-HT)
    • 3. 5-HT stimulates nerve endings in lamina propria
    • - these sensory neurons are in submucosal (meissner's plexus)
    • 4. Sensory neurons activate motor neurons in myenteric (Auerbach's) plexus
  15. Visceral Afferents of ANS
    Pain afferents travel w/ sypmathetics

    Stretch afferents travel w/ parasympathetics
Author
mnm2186
ID
30736
Card Set
Autonomic Nervous System
Description
Exam 2
Updated

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