Movement of stomach, small intestine and large intestine

Stomach

a. Filling

  • Smooth muscles of stomach relax when food enters into stomach from esophagus. This is receptive relaxation.

 

b. Peristalsis

  • This is involuntary movement of stomach muscles (contraction and relaxation).
  • This propels the food and mixes it with gastric juice to form chyme
  • Occurs about 20 secs (body of stomach to pyloric sphincter)

Small intestine

Shows two types of movement:

a. Segmentation:

  • Contraction of circular muscles that surrounds intestine
  • This Serves to mix a chyme and facilitates absorption.

 

b. Emptying

  • Process by which contents of intestine are removed into illio-caecum.

Large intestine

Contains two types

a. Haustral shutting

  • Large intestine is separated into segments i.e. called haustra.
  • Pacemaker cells in send signal causing the contraction at regular interval.
  • This disappears within 60 seconds.
  • This helps in mixing, absorption and propulsion.

 

b. Mass movements

  • Sudden and uniform peristaltic contraction of smooth muscles of gut
  • occurs in colon only
  • Occurs 2-3 times a day.
  • This help to force feacal matters to move towards rectum.
  • Contraction can be initiated by eating (Gastro-colic reflex)
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