The fine structure of nerve fibres in the hard palate of the Wistar albino rat.

The course of the nerve fibres and their nerve endings in the papillae on top of the intermolar rugae of rat's hard palate were studied by light- and electron-microscopy. Small myelinated and unmyelinated fibre bundles pass through the connective tissue of the basal region of the papilla, and split up in the intermediate region into solitary nerve fibres. In the top region only unmyelinated fibres were found. These fibres took the form of either lanceolate or free nerve endings. Some nerve endings made contact with the basement membrane of the epithelium. Occasionally free nerve endings were found between epithelial cells. The relationship of the unmyelinated fibres in the top of the papilla to the nerve fibres in the basal and intermediate regions was studied.