segmental contractions (colon)

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Colonic pressure is generated by segmental and propulsive contractions.

Segmental contractions:

  • localized periodic uncoordinated contractions
  • 2-3 times per minute
  • intraluminal pressure increased to 10-60 mmHg
  • there is little peristaltic movement
  • this type of contraction is inhibited if the patient has diarrhoea

Propulsive contractions:

  • occur 3-4 times per day
  • stronger than segmental contractions
  • stimulated by ingestion of food
  • increased frequency if the patient has diarrhoea

There is reduced colonic motor activity during sleep and unconsciousness.

There is an increase in segmental pressure after food. Also some drugs (e.g. cholinergic drugs and morphine) result in an increase in segmental pressure.

Last reviewed 01/2018