Observations on the development of the Sympathetic nervous system and suprarenal bodies in the sparrow

Abstract

1 The primary sympathetic primordia originate from the apinal cord, and are hence ectodermal in origin. 2 The primordia of the ganglin of the primary sympathetic chain are laid down metamerically at inter-somitic points. 3 The constituent cells of the primordia are derived from a. The neural crest; b. The dorsal root ganglia; c. The neural tube by way of the ventral root. 4 The primordia extend cranially and candally to form a continuous chain on either side. 5 The primaly ganglionic swellings extend dorso-laterally. The free ends of these extensions enlarge and becoming separated from the primary ganglia give origin to the definitive Sympathetic ganglia. 6 As in the case of the primary ganglia these definitive ganglis extend cranio-caudally and unite to form a continuous chain. 7 The primary sympathetic gives origin to a. The secondary sympathetic chains; b. The chromaffin cells of the medulla of the suprarend body; c. The coeliac and other ganglia; d. The unpaired ganglia in the cervical region.