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Adkins RB, et al.: Dysphagia associated with aortic arch anomaly in adults. Am .Surg 52:238, 1986.

Basson CT, et al.: Mutations in human TBX5 cause limb and cardiac malformation in Holt-Oram syndrome. Nat Genet 15:30, 1997.

Bruyer HJ, KargasSA, LevyJM: The causes and underlying developmental mechanisms of congenital cardiovascular malformation: a critical review. Am J Med Genet 3:411, 1987.

Clark EB: Cardiac embryology: its relevance to congenital heart disease. Am J Dis Child 140:41, 1986.

Coffin D, Poole TJ: Embryonic vascular development: immunohistochemical identification of the origin and subsequent morphogenesis of the major vessel primordia of quail embryos. Development 102:735, 1988.

Fishman MC, Chien KR: Fashioning the vertebrate heart: earliest embryonic decisions. Development 124:2099, 1997.

Harvey RP: NK-2 homeobox genes and heart development. Dev Biol 178:203, 1996.

Hirakow R: Development of the cardiac blood vessels in staged human embryos. ActaAnat 115:220, 1983.

Ho E, Shimada Y: Formation of the epicardium studied with the scanning electron microscope. Dev Biol 66:579, 1978.

Jiang X, Rowitch DH, Soriano P, McMahon AP, Sucov HM: Fate of the mammalian neural crest. Development 127:1607, 2000.

Kirklin JW, et al.: Complete transposition of the great arteries: treatment in the current era. Pediatr Clin North Am 37:171, 1990.

Li QY, et al.: Holt-Oram syndrome is caused by mutations in TBX5, a member of the Brachyury (T) gene family. Nat Genet 15:21, 1997.

Manasek FJ, Burnside MB, Waterman RE: Myocardial cell shape change as a mechanism of embryonic heart looping. Dev Biol 29:349, 1972.

Marvin MJ, DiRocco GD, Gardiner A, Bush SA, Lassar AB: Inhibition of Wnt activity induces heart formation from posterior mesoderm. Genes Dev 15:316, 2001.

Noden DM: Origins and assembly of avian embryonic blood vessels. Ann N Y Acad Sci 588:236, 1990.

Schott JJ, et al.: Congenital heart disease caused by mutations in the transcription factor NKX2-5. Science 281:108, 1998.

Skandalakis JE, Gray SW: Embryology for Surgeons: The Embryological Basis for the Treatment of Congenital Anomalies. 2nd ed. Baltimore, Williams & Wilkins, 1994.

Waldo K, Miyagawa-Tomita S, Kumiski D, Kirby ML: Cardiac neural crest cells provide new insight into septation of the cadiac outflow tract: aortic sac to ventricular septal closure. Dev Biol 196:129, 1998.

Outflow Tract Mesenchyme

(Fig. 12.1 A). The location of the bud along the gut tube is determined by signals from the surrounding mesenchyme, including fibroblast growth factors (FGFs) that "instruct"the endoderm. Hence epithelium of the internal lining of the larynx, trachea, and bronchi, as well as that of the lungs, is entirely of endodermal origin. The cartilaginous, muscular, and connective tissue components of the trachea and lungs are derived from splanchnic mesoderm surrounding the foregut.

Initially the lung bud is in open communication with the foregut (Fig. 12.1 B). When the diverticulum expands caudally, however, two longitudinal ridges, the tracheoesophageal ridges, separate it from the foregut (Fig. 12.2A). Subsequently, when these ridges fuse to form the tracheoesophageal septum, the foregut is divided into a dorsal portion, the esophagus, and a ventral portion, the trachea and lung buds (Fig. 12.2, B and C). The respiratory primordium maintains its communication with the pharynx through the laryngeal orifice (Fig. 12.2 D ).

Openings of pharyngeal pouches

Openings of pharyngeal pouches

Vertebrate Pharyngeal Pouches

Figure 12.1 A. Embryo of approximately 25 days gestation showing the relation of the respiratory diverticulum to the heart, stomach, and liver. B. Sagittal section through the cephalic end of a 5-week embryo showing the openings of the pharyngeal pouches and the laryngotracheal orifice.

A B Laryngotracheal orifice

Figure 12.1 A. Embryo of approximately 25 days gestation showing the relation of the respiratory diverticulum to the heart, stomach, and liver. B. Sagittal section through the cephalic end of a 5-week embryo showing the openings of the pharyngeal pouches and the laryngotracheal orifice.

Tracheoesophageal ridge Foregut Esophagus ^Jtercdum impar Lateral lingual swelling

Trachea

Respiratory diverticulum

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