Colon Movements Simplified: Segmentation and Mass Peristalsis

Colon Movements Simplified: Segmentation and Mass Peristalsis

Movements of large intestine.
Answer:

1. Mixing movements – segmentation contractions

• Large circular constrictions which appear in the colon are called mixing segmentations contractions
• Types:
  • Type I
    • Low pressure
    • Frequency-10-12/min
    • Duration – 5 sec
    • Aids in mixing of contents of colon
  • Type II
    • Large pressure
    • Frequency-1-2/min
    • Duration 30 sec
    • Aids in mixing of contents of colon Facilitates absorption

2. Propulsive movements – mass peristalsis

• It propels the faeces from colon towards anus
• Occurs few times every day
• Duration – 10 min in morning before or after breakfast
• Types
  • Type III
    • Small pressure
    • Longer duration
    • Propel contents towards rectum
  • Type IV
    • Occurs over large portion of colon simultaneously
    • Lasts for 3-4 min
    • Serve to empty the colon rapidly