Suggested Reading

Bellusci S, et al.: Fibroblast growth factor 10 (FGF 10) and branching morphogenesis in the embryonic mouse lung. Development 124:4867, 1997. Endo H, Oka T: An immunohistochemical study of bronchial cells producing surfactant protein A

in the developing human fetal lung. Early Hum Dev 25:149, 1991. Kozuma S, Nemoto A, Okai T, Mizuno M: Maturational sequence of fetal breathing movements.

Biol Neonate 60(suppl 1):36, 1991. Shannon JM, Nielson LD, Gebb SA, Randell SH: Mesenchyme specifies epithelial differentiation in reciprocal recombinants of embryonic lung and trachea. Dev Dynam 212:482, 1998. Whitsett JA: Molecular aspects of the pulmonary surfactant system in the newborn. In Chernick V, Mellins RB (eds): Basic Mechanisms of Pediatric Respiratory Disease: Cellular and Integrative. Philadelphia, BC Decker, 1991.

Fetal Lung Development

endoderm-lined cavity, the yolk sac and the allantois, remain outside the embryo (Fig. 13.1, A-D). In the cephalic and caudal parts of the embryo, the primitive gut forms a blind-ending tube, the foregut and hindgut, respectively The middle part, the midgut, remains temporally connected to the yolk sac by means of the vitelline duct, or yolk stalk (Fig. 13 .1 D). Development of the primitive gut and its derivatives is usually discussed in four sections: (a) The pharyngeal gut, or pharynx, extends from the buccopharyngeal membrane to the tracheobronchial diverticulum (Fig. 13.1 D); since this section is particularly important for development of the head and neck, it is discussed in Chapter 15. (b) The foregut lies caudal to the pharyngeal tube and extends as far caudally as the liver outgrowth. (c) The midgut begins caudal to the liver bud and extends to the junction of the right two-thirds and left third of the transverse colon in the adult. (d) The hindgut extends from the left third of the transverse colon to the cloacal membrane (Fig. 13.1). Endoderm forms the epithelial lining of the digestive tract and gives rise to the parenchyma of glands, such as the liver and pancreas. Muscle, connective tissue, and peritoneal components of the wall of the gut are derived from splanchnic mesoderm.

Hindgut

Endoderm

Amniotic cavity

Ectoderm

Angiogenic cell cluster

Buccopharyngeal membrane

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