Lymphoid nodules are found in the connective tissues lining the digestive, urinary, reproductive, and respiratory tracts. They are small, oval-shaped, and approximately a millimeter in diameter. They are not surrounded by a fibrous capsule. The collection of lymphoid tissues lining the digestive system is called mucosa-associated lymphoid tissue (MALT) because they are found in the mucous membranes lining the digestive tract. Clusters of lymphoid tissue found in the intestine and appendix are called aggregated lymph nodules, or Peyer’s patches. Tonsils are a group of lymphoid tissues found at the junction of the oral cavity, nasal cavity, and throat.