11 Jejunum and Ileum
Jejunum:
Imagine a powerful junk yard magnet that picks up valuable scrap metal, which can then be melted down and reused to create new steel products. Similarly, the second section of the small intestine, called the jejunum, plays a key role in absorbing important nutrients like carbohydrates, amino acids and fatty acids. Located after the first section (the duodenum), the jejunum is about 2.5 meters long and is lined with structures called plicae circulares and villi which help absorb nutrients before they move into the next part of the small intestine, the ileum.
Ileum:
The ileum, the last 3 meters of the small intestine, absorbs any nutrients not yet absorbed by the duodenum or jejunum, but mostly absorbs vitamins B12 and bile acids which are then recycled after absorption.
A defining characteristic of the ileum is the presence of Peyer’s patches, which are lymphoid nodules, essential to the gut’s immune function.
View the various sections of the small intestine below:
Figure 20 Anterior View of the small intestine
Do you understand this meme?
Hint: The small intestine while not occupying a large volume has a huge surface area which can reach the size of an entire tennis court. This scrunchie is a testament to the small intestine’s folds. For a refresher on the features of the small intestine click here: