Question

Most chemical digestion and absorption of key nutrients (carbohydrates, proteins and fats) occurs in the small intestine. However, we know that a small amount of chemical digestion continues to occur in the large intestine. What aids in this digestive process?

A. Pancreatic digestive enzymes.

B. Bile from the gallbladder.

C. A mixture of digestive enzymes entering from the small intestine and some produced by the enterocytes of the large intestine.

D. The activity of the large population of bacteria housed in the large intestine.

Answer 1

Answer option d . The activity of the large population of bacteria housed in the large intestine.

Absorption and secretion in large intestine

1 main function of colon is absorbtion of water,it absorb 90% of water ,main site is caecum and ascending colon

2large Intestine can absorb sodium, potassium,chloride,glucose,and certain vitamin with net secretion of potassium and bicarbonate but it can't absorb protein,fat and calcium

3 no digestive enzymes are secreted in colon

4 at birth colon is sterile but colonic bacterial flora become established in early life which help in

• Synthesis of vit k
• Production of carbondioxide, hydrogen sulphide and methane which contribute to flatulence
• Organic acid formed from Carbohydrates by bacteria are responsible for slightly acidic reaction of stool
• Pigments formed frombile by instestinal bacteria are responsible for brown color of stool