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• 1 HAP

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• Random hydrolysis of peptide bonds (in vitro)

  10-12 hours in 12 mol/L HCl at 105 degrees

• Digestion and propagation of chime in GI tract

  Controlled by combined action of motor activity of sphincters and gut wall

• Parasympathic nervous system

  - Gut receives input from autonomic nervous system (ANS)
  - Connects by vagus neve and pelvic nerve
  - Both contain efferent (motor) and afferent (sensory) fibers --> inform brain about gut status
  - Neurotransmitter is acetylcholine

• Intrinsic nervous system (ENS)

  - Most ENS cells are derived from vagal neural crest cells (NCCs)
  - Consists of myenteric and submucosal plexus
  - Contain many neurotransmitters and hormones
  - Major part of intergration in control of gut motility

• Sympathic nervous system

  - Part of extrinsic neurvous system
  - Inhibition of gut motility
  - Neurotransmitter is noradrenalin

• Secretory and motor behaviours - neurocrine

  - Mediated by nerves, synapses and neurotransmitters
  - Transmission in gut or central nervous system

• Secretory and motor behaviours - endocrine

  - Release of transmitters (hormones) by entero-endocrine sensore cells --> reach their target via blood

• Secretory and motor behaviours - paracrine

  - sensing cell releases a transmitter substance that mediates the response in neighbouring cells
  - Acid secretion in stomach is partially paracrine regulated

• Migrating motor complex - MMC

  Clean small bowel of any remaining material and prevents bacterial overgrowth from gut flora in large bowel
  - Every 90 minutes
  - Stops when food enters stomach (digestive period)
  - Phase 1: motor quiescence (40 min. rest)
  - Phase 2: irregular movements (40 min start peristalsis)
  - Phase 3: strong peristaltic contractions (10 min. max peristalsis) --> remove indigestible food

• Transit time - small bowel

  1.5 hour