REGULATIONS OF THE DIGESTIVE SYSTEM

• Enteric nervous system (ENS) - regulates most of the nerves of the digestive tract
• 3 Major types of enteric neurons:

  • Enteric sensory neurons - detect changes in the digestive tract
  • Enteric motor neurons - contraction and relaxation of smooth muscle
  • Enteric interneurons - connect sensory and motor neurons
• Hirschprung disease (megacolon) - developmental disorder caused by the absence of enteric neurons in the distal large intestine
• 3 major ENS neurotransmitters:

  • Acetylcholine - stimulates digestive tract motility
  • Norepinephrine - inhibits digestive tract motility
  • Serotonin - same as ACh; produced by endocrine cells
• Histamine - help local reflexes within the ENS to control local digestive tract movements