CBSE Class 10 Answered

Loose motions, also called diarrhoea, occurs because more fluid passes through the large intestine (colon) than that organ can absorb. Normally, stool is 60 to 90% water; diarrhoea mainly results when the percentage exceeds 90%. Stool may contain too much water if it travels too quickly through the digestive tract, if certain components of the stool prevent the large intestine from absorbing water, or if water is being secreted by the large intestine into the stool. As a rule, the colon can absorb several times more fluid than is required on a daily basis. However, when this reserve capacity is overwhelmed, diarrhea occurs. Rapid transit of stool is one of the most common causes of diarrhea. For stool to have normal consistency, it must remain in the large intestine for a certain amount of time. Stool that leaves the large intestine too quickly is watery.