Skin photoreceptors in the leopard frog
INTRODUCTION INTRODUCTION EXPERIMENTAL METHODS OBSERVATIONS DISCUSSION ELECTODERMOGRAM MECHANISM CONCLUDING REMARKS REFERENCES It is an engaging thought that the great sense organs concentrated in the head region of vertebrates were all derived from primitive systems of widely diffused skin receptors. In this sense, one can think of the receptors of hearing as derived from cutaneous touch spots, with which they share many physiological properties; the organ of equilibrium the cristae of the semicircular canals from deep pressure receptors; smell from chemoreceptors that remain widely distributed over the bodies of the mucous - skinned fishes and amphibia and have withdrawn into the mucous area of the mouth in land vertebrates. In all these cases, the transition from skin receptors to sense org ...