[Development of human olfactory receptors].

The development of the olfactory epithelium in 7-, 8-, 9-, 10- and 11-week old human fetuses was followed using electron microscopy. The differentiation of receptor and supporting cells and the establishment of Bowman's glands and the formation of olfactory nerve have been observed. In 7 week old fetuses the development of peripheral processes with olfactory knobs, lacking hairs, and of central processes with growth cones penetrating the connective tissue has been followed. A typical olfactory knobs possessing hairs were first found in 9 week old fetuses, the number of those progressively increasing starting from the 10 week age. At the 11th week of the development, completely differentiated olfactory cells were found, which are suggested to be capable of normal olfactory performance.