Which part of the small intestine primarily absorbs sugars, amino acids, and fatty acids?

• A. Jejunum
• B. Duodenum
• C. Ileum
• D. Cecum

Answer: (A)

Sugars, amino acids, and fatty acids are absorbed mainly in the jejunum, the middle part of the small intestine. Its lining has many tall villi and microvilli, which dramatically increases surface area for uptake. Enterocytes in this region are rich in transporters for monosaccharides like glucose and galactose, as well as amino acids, allowing efficient transfer into the bloodstream. Fat absorption also occurs here as fatty acids and monoglycerides, delivered by bile-acid–assisted micelles, are taken up by enterocytes, reassembled into triglycerides, and packaged into chylomicrons for transport.

The duodenum mostly handles digestion and some early absorption, the ileum specializes in reabsorbing bile acids and vitamin B12, and the cecum is part of the large intestine involved in water and electrolyte absorption.