Figures & data
Figure 1. Schematic diagram showing extrinsic nerves and intrinsic innervation of the respiratory tract. (A) Extrinsic neurons have their cell bodies in the jugular, nodose, and petrosal ganglia within the brainstem. These extrinsic neurons extend their axons via the vagus nerve (in red and blue) and provide sensory and parasympathetic respiratory innervation respectively. In addition, sensory neurons located in the dorsal root ganglion also provide extrinsic innervation (in green) to the respiratory tract. (B) Neural crest-derived intrinsic neurons (in blue) cluster within the trachea and main bronchi. Intrinsic neurons express the Ret receptor. The survival, proliferation, and/or differentiation of intrinsic neurons within the respiratory tract is dependent on the GDNF family ligands that include GDNF and neurturin. (C) ASM in the embryonic lung expresses BDNF. BDNF serves as a target-derived neurotrophic signal for extrinsic innervation by TrkB+ extrinsic nerves. The lung is largely devoid of intrinsic neurons.
