Why does the wall of the small Intestine need a large surface area?
1 Answer
For better digestion of food and absorption of nutrients.
Explanation:
The small intestine is the site of terminal food digestion, nutrient (product of digestion) absorption and endocrine secretion. The process of digestion is completed here. Because large intestine only absorb water, form stool and produce mucus.
To ensure complete digestion and absorption of nutrients the area of contact between nutrients and intestinal surface is needed to be high enough.
A large surface area is an important characteristic in an organ where absorption occurs so intensely. The small intestine is 5 meters long. the plicae increase the surface area 5 fold, villi increase it 10 fold, microvilli increase it 20 fold. Together these processes increase surface area up to 200 square meters.
The diagram shows plicae (folds), villi and microvilli in the wall of small intestine :
