Figure 22-20. The four main differentiated cell types found in the epithelial lining of the small intestine.

Figure 22-20The four main differentiated cell types found in the epithelial lining of the small intestine

All of these are generated from undifferentiated multipotent stem cells living near the bottoms of the crypts (see Figure 22-19). The microvilli on the apical surface of the absorptive (brush-border) cell provide a 30-fold increase of surface area, not only for the import of nutrients, but also for the anchorage of enzymes that perform the final stages of extracellular digestion, breaking down small peptides and disaccharides into monomers that can be transported across the cell membrane. (After T.L. Lentz, Cell Fine Structure. Philadelphia: Saunders, 1971; R. Krsti´c, Illustrated Encyclopedia of Human Histology. Berlin: Springer-Verlag, 1984.)

From: The Airways and the Gut

Cover of Molecular Biology of the Cell
Molecular Biology of the Cell. 4th edition.
Alberts B, Johnson A, Lewis J, et al.
New York: Garland Science; 2002.
Copyright © 2002, Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter; Copyright © 1983, 1989, 1994, Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts, and James D. Watson .

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