Outside the crypts, the epithelium will typically look like ordinary stratified squamous epithelium. Inside the crypts, where cells of the immune system often invade the epithelium, it will be difficult to find the boundary between epithelium and lymphoid tissue. Tissue preservation is not that great, but with a little bit of patience you should be able to find high-endothelial venules in the lymphoid tissue. Sketch the organisation of the tissue at low magnification. However, the most prominent accumulations occur in the ileum in the form of Peyer's patches and in the appendix.
Some crypts penetrate deep into the lymphoid tissue.
The epithelium in contact with the lymphoid tissue is specialised to facilitate the contact of antigens with cells of the immune system. Occasionally you will see crypts extending deep into the lymphoid tissue. Compare the epithelium embedded in lymphoid tissue with that closer to the lumen of the appendix. Goblet cells are rare or absent and the epithelium appears low columnar.