Final answer:
MALT contains lymphatic nodules, which form Peyer's patches in the small intestine's mucosal layer, performing critical functions in the body's immune response to prevent bacteria from entering the bloodstream.
Step-by-step explanation:
MALT contains lymphatic nodules which are a large collection of lymphatic tissue within the wall of the GI tract. The mucosa of the small intestine is studded with MALT. These include solitary lymphatic nodules and, more significantly, aggregations known as Peyer's patches, which are concentrated in the distal ileum. Peyer's patches play a crucial role in preventing bacteria from entering the bloodstream and are part of the body's immune response to ingested substances. They contain specialized cells that sample material from the intestine and transport it to lymphoid follicles to initiate an immune response. Over time, these patches become less distinct, which corresponds with changes in immune system activity as one ages.