The lamina propria consists of loose connective tissue. The wispy strands of material in this image are collagen fibers, and the dark, elongate nuclei associated with them (as seen in the lower right corner) are fibrocytes. The cells at the arrows are plasma cells. Note the pale ("negative-staining") region next to the nucleus and the basophilic cytoplasm. Can you identify the organelles responsible for each of these staining characteristics? Midway between the plasma cells are three cells with similar nuclei, but scant, basophilic cytoplasm. These are lymphocytes. Macrophages are hard to identify if they are not active in phagocytosis. Neutrophils and eosinophils, when present, will look like they do in the blood.