Mechanoreceptors in the Beaks of Birds

Abstract

For more than a century two kinds of mechanoreceptors have been known in the beaks of birds, the Grandry and the Herbst corpuscles. The latter were originally considered by Herbst (1848) as the Pacinian corpuscles of birds and recent ultrastructural work (Halata, 1971), as well as physiological studies (Dorward, 1970; Dorward and McIntyre, 1971) have established that there is in fact a great similarity between Herbst and Pacinian corpuscles. Since Merkel’s (1875) first detailed study of Grandry corpuscles it has been assumed that the specialized cells in the Grandry corpuscle would be structurally and functionally similar to Merkel’s Tastzellen (tactile cells) in the epidermis of other vertebrates. In recent times it has been assumed that the Grandry corpuscles — like various Merkel cell receptors — would give rise to a slowly adapting discharge.

Supported by Deutsche Forschungsgemeinschaft SFB 33.