Tactile corpuscles of Grandry

[2][4] Electrophysiological studies have shown that Grandry corpuscles function as rapidly adapting velocity detectors.

[6] Grandry corpuscles are found in the superficial portion of the dermis in bill skin and oral mucosa of aquatic bird species.

[1] In the tip of the bills of ducks and geese, Grandry corpuscles can also be found within dermal papillae which extend through tubules into the maxillary and mandibular nails of the beak.

These papillae, which contain many mechanoreceptors and end in keratinous caps, make up a distinct sensory region known as the bill tip organ.

[9][1] Krogis, who studied the dorsal bill skin of the domestic duck, mallard, Eurasian teal, garganey, and tufted duck, found that Grandry corpuscle concentration tended to increase at both the base and tip of the bill.

[8] Two major features of these cells are 1) large bundles of microfilaments and 2) vesicles with electron-dense cores in the cytoplasm.

[2] The outermost layer of the Grandry corpuscle consists of a partial capsule containing fibroblast cells and collagen protein.

[10] Because both receptors contain Merkel-like cells surrounding a nerve axon, they can be categorized as Merkel Cell-Neurite complexes.

Idé and Munger (1978) pointed out that mammalian Merkel corpuscles are unlike the avian form in that they are slowly adapting and located in the epidermis, whereas avian Grandry and Merkel corpuscles are both fast adapting and found in the dermis.