Development of the olfactory epithelium in man.

The development of the olfactory epithelium in 7-, 8-, 9-, 10- and 11-week-old human fetuses was studied by electron microscopy. The differentiation of the receptor and supporting cells, and formation of the Bowman glands and the olfactory nerve were observed. In 7-week-old fetuses develop the peripheral processes with the olfactory knobs lacking hairs, as well as the central processes with the growth cones. The olfactory knob with hairs was first found in 9-week-old fetuses, their number progressively increasing starting from the 10th week. The completely differentiated olfactory cells were found by the 11th week. They are suggested to be capable to carry out the olfactory function.