title: Electron microscopic study on the innervation of the human lower respiratory tract: evidence of adrenergic nerves.
abstract: Samples of human lung were studied electron microscopically after fixation with glutaraldehyde and osmium tetroxide. Three different types of nerve profiles were found in the human lower respiratory tract. Type I nerve profiles contained small agranular vesicles 30-50 nm and large granular vesicles ranging from 60 nm to 210 nm. Type II nerve profiles contained small granular vesicles 30-50 nm and a few large granular vesicles ranging from 60 to 120 nm. Type III nerve profiles contained predominantly large irregular vesicles ranging from 60 to 210 nm, and only a few small agranular vesicles. The present electron microscopic results indicate that the smooth muscle layer of human bronchial tree receives adrenergic nerves.
mesh_terms: D000320:Adrenergic Fibers / Q000648:ultrastructure*; D000328:Adult; D001980:Bronchi / Q000294:innervation; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D009130:Muscle, Smooth / Q000648:ultrastructure; D012137:Respiratory System / Q000294:innervation*