- Tonsils: Located in the pharyngeal region, they contain multiple lymphoid follicles with germinal centers. The surface is lined by stratified squamous epithelium. - Peyer's Patches: Found in the ileum of the small intestine, these are large aggregates of lymphoid tissue. They have a specialized epithelium known as follicle-associated epithelium (FAE), which includes M cells. - BALT: Present in the bronchi, BALT contains lymphoid follicles similar to those in Peyer's patches but is associated with the respiratory epithelium.
