This is a plastic section of small intestine. Find the luminal surface of this section and locate the lamina propria and submucosa. Review the epithelium of the villi and the mesothelium. Be able to distinguish between an eosinophil and a mast cell. The macrophages are large cells with a pale cytoplasm containing vacuoles.
Fibroblasts are usually thin elongated cells with relatively little cytoplasm visible.
In addition, the nuclei may vary in their shape from ellipsoid to something more triangular or diamond-like. Examine the outer mesothelial surface. The lamina propria and submucosa of the appendix contain large groups of densely stained lymphocytes. Lymphocytes have a dense nucleus with little cytoplasm. At higher power, note the numerous eosinophils.