Aggregates of lymphoid tissue present in the distal portion of the small intestine are known as

In the wall of the small intestine, lymphatic tissues are called Peyer's patches. These are groups of lymph nodules that are most numerous in the ileum. They produce lymphocytes.

Rugae are prominent folds found in an empty stomach. The mucous membrane of the small intestine is grown into many finger-like projections known as villi.