BIO380H5 Lecture Notes - Lecture 12: Foregut, Collagen, Porton
Document Summary
Lecture 12 digestive and respiratory systems (ch. The digestive system: the digestive tube is bounded at its cephalic end by the membrane and at its caudal end by the cloacal plate. Cells need to be differentiated by the expressing of a combination of hox genes. Development of the esophagus: just caudal to the most posterior pharyngeal pouches of a 4-week-old embryo, the pharynx becomes abruptly narrowed, and a small ventral outgrowth (lung bud) appears (single out pocketing of the pharynx). The region of foregut just caudal to the lung bud is the esophagus. This segment is initially very short, with the stomach seeming to reach almost to the. In the second month of development, the gut elongates considerably, the esophagus assumes nearly postnatal proportions in relation to the location of the stomach. In its earliest stages, the endodermal lining epithelium of the stratified columnar: by 8 weeks, the epithelium has partially occluded esophagus, and large vacuoles appear.
