BIO380H5 Lecture Notes - Lecture 30: Pleural Cavity, Fibroblast Growth Factor, Foregut
Document Summary
The future respiratory gut is located in the ventral foregut. Specification by wnt and fgf signals from the adjacent mesoderm. Late 4th week- lung buds begin to protrude from the posterior part of the respiratory endoderm. Creation of a septum separating the newly formed trachea from the esophagus from the mesodermal ridges growing inward which are present dorsal to the lung buds. Interactions with surrounding mesoderm = trachea + lung buds (respiratory diverticulum) elongates and begins a set of 23 bifurcations (division into two) Initial formation of the respiratory diverticulum up to the formation of all major branchopulmonary segments. Developing lungs grow and begin to fill the bilateral pleural cavities. Formation and growth of the duct systems within the bronchopulmonary segments before their terminal portions form respiratory components. Formation of respiratory bronchioles due to budding of the terninal components that formed during the pseudoglandular stage.
