Peristalsis (Edexcel IGCSE Biology)

Spec point — 2.28 · understand how food is moved through the gut by peristalsis

Peristalsis

• Peristalsis is a mechanism that helps moves food along the alimentary canal

• Firstly, muscles in the walls of the oesophagus create waves of contractions which force the bolus along

• Once the bolus has reached the stomach, it is churned into a less solid form, called chyme, which continues on to the small intestine

• Peristalsis is controlled by circular and longitudinal muscles

  • Circular muscles contract to reduce the diameter of the lumen of the oesophagus or small intestine
  • Longitudinal muscles contract to reduce the length of that section the oesophagus or the small intestine

• Mucus is produced to continually lubricate the food mass and reduce friction

• Dietary fibre provides the roughage required for the muscles to push against during peristalsis

Muscles in the alimentary canal contract rhythmically to move the partially digested food along in a wave-like action