Abstract
One of the aims of systems biology is to model and discover properties of cells, tissues and organisms functioning as a system. In recent years, studies in the adult Drosophila gut have provided a wealth of information on the cell types and their functions, and the signaling pathways involved in the complex interactions between proliferating and differentiated cells in the context of homeostasis and pathology. Here, we document and discuss how high-resolution ultrastructure studies of organelle morphology have much to contribute to our understanding of how the gut functions as an integrated system.