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AUTONOMIC PHARMACOLOGY & PHYSIOLOGY

Peripheral
  Anatomy
  Clinical-Anatomic
  Disorders
  Pharmacology
  Physiology
Central
  Baroreceptor pathways

AUTONOMIC ANATOMY & PHARMACOLOGY: PERIPHERAL

Autonomic Nervous System: Anatomy


From: University of Queensland

Baroreceptor Pathways: Central

Principles
  • Preganglionic: Motor neurons leaving CNS release acetylcholine (ACh)
    • Acts on nicotinic AChRs.
    • Somatic motor neuron synapses contain AChRs
      • Blocked by: α-Bungarotoxin & Tubocurarine
    • Autonomic motor neuron (preganglionic) synapses (in ganglia) contain
      • Nicotinic AChRs: Blocked by hexamethonium, but not by α-bungarotoxin
      • Some muscarinic receptors: Blocked by atropine
      • Chromaffin cels in the adrenal medulla
        • Modified sympathetic ganglion cells
        • Contain only nicotinic receptors
  • Postganglionic axons
    • Parasympathetic terminals release ACh: Acts on muscarinic AChRs
    • Sympathetic terminals
      • Usually release noradrenaline
        • Acts on α, β1, or β2 adrenoceptors
      • Eccrine sweat glands and pilierector muscles: ACh acts on muscarinic AChRs
  • Anatomy
    • Sympathetic system arises from thoracic & lumbar levels
    • Parasympathetic system arises from cranial & sacral levels


ORGAN-SPECIFIC EFFECTS OF AUTONOMIC ACTIVITY

Sympathetic vs Parasympathetic
General Principles
  • Parasympathetic vs Sympathetic systems
    • Often have antagonistic effects in each organ
  • Sweat glands & most vascular smooth muscles: Only sympathetic innervation
  • Ciliary muscle of the eye: Only parasympathetic innervation
  • Bronchial smooth muscle
    • Only parasympathetic innervation: Constriction
    • Smooth muscle sensitive to circulating adrenaline: Dilation
  • Salivary glands: Systems produce similar, rather than opposite, effects

OrganSympathetic StimulationParasympathetic Stimulation
Heart ↑ Rate (β1 & β2) ↓ Rate
↑ Contractile force (β1 & β2) ↓ Contractile force
↑ Conduction velocity ↓ Conduction velocity
Artery Constriction (α1) Dilation
Dilation (β2)
Vein Constriction (α1)  
Dilation (β2)
Lung Bronchial muscle:
Relaxation (β2)
Bronchial muscle contraction
Bronchial gland secretion
Gastrointestinal tract ↓ Motility (β2) ↑ Motility
Sphincter: Contraction (α) Sphincter: Relaxation
Liver Glycogenolysis (β2 & α) Glycogen synthesis
Gluconeogenesis (β2 & α)
Lipolysis (β2 & α)
Kidney Renin secretion (β2)  
Bladder Detrusor: Relaxation (β2) Detrusor: Contraction
Sphincter: Contraction (α) Sphincter: Relaxation
Uterus Contraction: Pregnant uterus (α)  
Relaxation: Pregnant &
non-pregnant uterus (β2)
Eye Pupil: Dilate (α) Pupil: Constrict
Lacrimal gland secretions
Salivary glands
 Submandibular
 Parotid
Viscous secretions (α) Watery secretions


Disorders: Clinical-Anatomic Associations



T Willis
Autonomic & Other nerves: In Cerebri Anatome

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5/1/2018