Intermediate cells constitute most of the cells found within the intestinal stem cell niche that is located in the lower half of the intestinal gland. These cells constitute the amplifying compartment of the cells that are still capable of cell division and usually undergo one or two divisions before they become committed to differentiation into either absorptive or goblet cells. These cells have short, irregular microvilli with long core filaments extending deep into the apical cytoplasm and numerous macular (desmosomal) junctions with adjacent cells. Small mucin-like secretory granules form a column in the center of the supranuclear cytoplasm. Intermediate cells that are committed to becoming goblet cells develop a small, rounded collection of secretory granules just beneath the apical plasma membrane; those that are committed to becoming absorptive cells lose the secretory granules and begin to show concentrations of mitochondria, rER, and ribosomes in the apical cytoplasm.
GALT is prominent in the lamina propria of the small intestine.
As noted above, the lamina propria of the digestive tract is heavily populated with elements of the immune system; approximately one-fourth of the mucosa consists of a loosely organized layer of lymphatic nodules, lymphocytes, macrophages, plasma cells, and eosinophils in the lamina propria (Plate 55, page 608). Lymphocytes are also located between epithelial cells. This GALT serves as an immunologic barrier throughout the length of the gastrointestinal tract. In cooperation with the overlying epithelial cells, particularly M cells, the lymphatic  FOLDER 17.5 Functional Considerations: Immune Functions of the Alimentary Canal