Nerve endings in the epithelium and submucosa of human epiglottis.

An electron-microscopic study of the sensory innervation of human epiglottis was undertaken. The nerve supply of this structure was abundant; numerous free unmyelinated nerve endings of 2.5-3 microns were observed in the stratified epithelium of the epiglottis associated with clear cells containing mitochondria, rough endoplasmic reticulum, microtubules and dense-cored granules. The nerve and cell complex resembled a corpuscular structure, probably of a quimiosensitive character. In the submucosa, unmyelinated nerves were observed which may come from deeper myelinated trunks, and some of them entered the epithelium. Encapsulated corpuscles were also found in the submucosa. Four elements could be distinguished: nerve endings, lamellar cells, interlamellar substance, and capsule. Our observations at an ultrastructural level complete previous observations by means of light microscopy indicating that the epiglottis is a zone with an important innervation in the epithelium as well as in the submucosa. This sensory innervation probably bears a relation to reflexes, such as cough and deglution, to protect the airways.