Human Anatomy - Lab 39 Step 12

Laboratory 39. Intestines and Pancreas
Step 12. The Jejunum and the Ileum

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Now, make a longitudinal cut from the jejunum to the ileum . Observe the circular mucosal folds, called plicae circulares, on the internal surface of the jejunum and ileum. The plicae circulares in the proximal jejunum are more pronounced and more numerous than they are in the ileum.

There are also differences in the lymphatic system in these regions. In the distal ileum, submucosal aggregates of lymphatic nodules called Peyer's patches, are visible and are often palpable (Figure 39.5). They increase in number as the ileum approaches the cecum. Peyer's patches are not present in the jejunum.

Links and References:
Grant's: 2.69
Netter: 280
Rohen/Yokochi: 279, 278