Reabsorption of Water and Defecation
1. The large intestine does not secrete any enzyme.
2. Water, minerals and vitamins are absorbed by the large intestine.
3. Peristalsis is slow in the large intestine.
4. Undigested and unabsorbed matter in the faeces are discharged into the rectum.
5. When the rectum is full, a feeling of weight causes a desire for voiding.
6. Peristaltic contraction of the rectum, aided by contraction of the abdominal muscles, voids the faeces through the anus. The process is called defecation.
7. If the undigested matter passes through the large intestine too slowly, too much water will be absorbed. The faeces would become very hard and dry, and this results in constipation.
8. We should eat more dietary fibre and drink more water to avoid constipation.