Neural Crest, Great Arteries, and Outflow Septation

Abstract

Abstract The neural crest is a population of multipotential cells that delaminate from the dorsal neural tube and migrate widely throughout the body. Based on the cells’ axial level of origin from the neural tube, the neural crest is divided into cranial and trunk regions. Both cranial and trunk neural crest cells give rise to the peripheral nervous system and melanocytes. However, only cranial neural crest has the potential to give rise to “ECTOMESENCHYMAL” CELLS. Ectomesenchymal cells take part in development of a wide variety of structures in the head, neck, and heart. Because of the importance of neural crest-derived ectomesenchyme in heart development, a subregion of the cranial neural crest has been called “cardiac neural crest.” Cardiac neural crest cells also support development and final patterning of the great arteries of the thorax. Neural crest cells are essential for modulating signaling in the caudal pharynx, which is important for normal development of the arterial pole of the heart (see Chapter 6). A subpopulation of cardiac neural crest cells migrates from the caudal pharynx into the cardiac outflow tract to form the aorticopulmonary septum, which divides the common arterial blood flow into pulmonary and systemic streams in animals with lungs. In addition to these roles of ectomesenchymal cells derived from neural crest, neural derivatives provide the innervation of the heart. Cardiac innervation is covered in Chapter 13.