Development and Differentiation of the Gastrointestinal System

This chapter outlines the basic mechanisms by which the embryo achieves a spatial pattern, setting the stage for further developmental steps. Early development of the gastrointestinal tract is characterized by gastrulation and endoderm formation, followed by midline migration of anterior and posterior invaginations resulting in a gut tube. After gastrulation, the endoderm undergoes more easily recognizable changes of organogenesis. The chapter then focuses on the known molecular mechanisms that guide development of the liver, the pancreas, and the lumenal gastrointestinal tract. Gastrointestinal organogenesis can be divided into several overlapping phases: specification, budding, morphogenesis and cell fate determination. Next, the chapter reviews important events during the functional maturation of the gastrointestinal tract. Finally, it focuses on specific diseases that highlight the relationship between molecular events and clinical consequences.