走査型電子顕微鏡によるヒト胎児ラセン器の発生学的研究

抄録

The surface structure of the 7 human fetus cochleas (from 10 weeks to 25 weeks old) was observed by scanning electron microscope. The results are as follows: 1. A primitive figure of sensory hairs of both inner hair cells and outer hair cells was observed in the 13 week old fetus, 2. In the 13 week old fetus, a kinocilium was observed in each inner hair cell and in the 14 week old fetus, a kinocilium was also observed in each outer hair cell. Most of these kinocilia had disappeared in the 26 week old fetus, 3. The development of shape inner hair cell starts earlier than that of outer hair cell. Inner hair cells show remarkable maturation from 13 weeks old to 17 weeks old of embryonic age; outer hair cells mature remarkably from 14 weeks old to 23 weeks old of embryonic age, 4. External inner hair cells and the fourth row of outer hair cells were found in the mid-term embryonic age, and 5. Inner hair cells, outer hair cells and supporting cells are considered to be mature enough to perceive sound in the 23-26 week old fetus.