Question

Which of the following is the primary absorptive process in the large intestine?

• A. Active transport of $N{a}^{+}$ from the lumen to the blood
• B. Absorption of amino acids and fructose
• C. Active transport of potassium from the lumen to the blood
• D. Active absorption of $HC{O}_3$ into the blood

Answer 1

The correct option is A Active transport of $N{a}^{+}$ from the lumen to the blood

A. Active transport of Na+ from the lumen to the blood.

Solution: Large intestine has a high capability for active absorption of sodium ions which create a gradient for chloride ions absorption as well. This forms an osmotic gradient across the large intestinal mucosa causing absorption of water.