The epithelial innervation of the lower respiratory tract of the cat.

A quantitative ultrastructural study of intra-epithelial axons in the lower respiratory tract of the cat has compared the innervation at four airway levels, two extra- and two intrapulmonary. The morphology of intra-epithelial axons has been described, and their association with different epithelial cell types recorded. Their morphology suggests that most are afferent in function.