Cell types of the intestinal epithelium

The intestinal epithelium consists of different cell types. The most abundant cells are enterocytes, also known as intestinal absorptive cells, because their apical membrane and glycocalix is packed with digestive enzymes and transporters. The enterocytes are not only responsible for nutrient absorption, they also play an important role in processing antigens and presenting them to T cells.

The brush cells are another type of epithelial cell with microvilli on the apical side. Although brush cells have longer microvilli, they have a thinner glycocalix than enterocytes. The function of brush cells is still under investigation, but it has been hypothesized that they have a receptor role.

Goblet cells are easily distinguished from the other two cell types as they produce and secrete mucus into the lumen of the small intestine. Mucus is mainly composed of mucin glycoproteins, which form a gel-like layer covering the epithelial cells. This helps to protect the cells from physical damage by acting as a lubricant and the gel-like web of macromolecules also forms a barrier against bacteria cells.

Figure 1: Light microscopy image of a goblet cell surrounded by entherocytes.