what is the upper part of the small intestine called
1 Jejunum: This is the midsection of the small intestine, connecting the duodenum to the ileum. 2  It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area. 3  Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.