Kimura Mitsuhiro, Umehara Tsuyoshi, Udagawa Jun, Kawauchi Hideyuki, Otani Hiroki
Department of Otorhinolaryngology, Faculty of Medicine, Shimane University, Izumo, Japan.
Congenit Anom (Kyoto). 2009 Sep;49(3):102-7. doi: 10.1111/j.1741-4520.2009.00233.x.
Human olfactory epithelium becomes functional at birth, but prenatal development remains unclear. In the present study, we aimed to clarify the development of human olfactory epithelium using scanning electron microscopy (SEM).
The development of human olfactory epithelium was observed in 24 externally normal fetuses, which were formalin-fixed and long-preserved, with a crown-rump length (CRL) of 102-336 mm (gestational week 14-38). The olfactory mucosa in the superior wall of the nasal septum near the choana were dissected and observed under SEM. We examined the number of olfactory vesicles per unit area, diameter of olfactory vesicles, and number and length of cilia on olfactory vesicles.
At circa (ca) CRL 100 mm (ca 14 weeks), olfactory epithelium displayed several olfactory vesicles with 1-2 short cilia per unit area. At ca CRL 150 mm (ca 18 weeks), olfactory vesicles were present in small clusters, and cilia were longer. At CRL lager than 225 mm (ca 26 weeks), olfactory vesicles became located separately from each other, while length and number of cilia per olfactory vesicle were further increased.
The present findings suggest that fetal olfactory epithelium becomes morphologically almost the same as that in adults in late gestation, much later than previously thought.
人类嗅觉上皮在出生时开始发挥功能，但产前发育情况仍不清楚。在本研究中，我们旨在利用扫描电子显微镜（SEM）阐明人类嗅觉上皮的发育情况。
观察了24例外观正常的胎儿，这些胎儿经福尔马林固定并长期保存，顶臀长度（CRL）为102 - 336毫米（妊娠第14 - 38周）。解剖并在扫描电子显微镜下观察了靠近鼻后孔的鼻中隔上壁的嗅黏膜。我们检查了每单位面积的嗅泡数量、嗅泡直径以及嗅泡上纤毛的数量和长度。
在大约CRL 100毫米（约14周）时，嗅觉上皮每单位面积显示有几个嗅泡，每个嗅泡有1 - 2根短纤毛。在大约CRL 150毫米（约18周）时，嗅泡成小簇存在，且纤毛更长。当CRL大于225毫米（约26周）时，嗅泡彼此分开，同时每个嗅泡的纤毛长度和数量进一步增加。
目前的研究结果表明，胎儿嗅觉上皮在妊娠晚期在形态上几乎与成人相同，比之前认为的要晚得多。
