BIOL 3010 Lecture Notes - Lecture 20: Activin And Inhibin, Alveolar Cells, Fgf10
Document Summary
Gastrointestinal system: development of the gut tube, gut tube forms from folding of lateral edges of endoderm. Three regions (foregut, midgut, hindgut) and associated openings. Gut tube is embedded in mesentery, which suspends it in the coelom, both of splanchnic mesoderm origin: morphogenesis of gut tube derivatives occurs in weeks 4 through 12. Esophagus: becomes occluded then vacuoles reopen it. Stomach and intestine: rotations needed to result in final location. Each region (fore-, mid-, hindgut) specializes in craniocaudal direction (see chart, p. 4) area. Following this, there is cellular differentiation and innervation (nccs), then maturation to final form: shh/ihh is responsible for radial patterning of gut tube. Epithelium (endoderm): shh/ihh expr throughout gut except for pancreas. Lamina propria / submucosa (mesoderm): shh/ihh activates ptc and bmp4 and inhibits diffn of smooth muscle from mesenchyme. Smooth muscle layer (mesoderm): outer most layer. Posterior hox genes induced by shh plays role in regionalization.