Gilpin S A, Gosling J A
J Anat. 1983 Oct;137 (Pt 3)(Pt 3):503-12.
A series of human fetal and neonatal specimens ranging in age from the second month of intrauterine development to 4 1/2 years after birth has been examined using histological and histochemical techniques. In both sexes histologically differentiated smooth muscle cells were evident in the bladder wall from the 52 mm crown-rump length stage onwards--urethral smooth muscle was not distinguishable until 119 mm crown-rump length. In addition to relatively late differentiation, urethral smooth muscle was histochemically distinct from the urinary bladder detrusor muscle. Sex differences in the arrangement and innervation of smooth muscle in the proximal urethra have also been observed, and these findings lend support to the presence of a pre-prostatic urethra sphincter. It seems likely that this sphincter acts principally to prevent reflux of ejaculate into the bladder during seminal emission.
使用组织学和组织化学技术对一系列人类胎儿和新生儿标本进行了检查，这些标本的年龄范围从子宫内发育的第二个月到出生后4岁半。在两性中，从冠臀长52毫米阶段开始，膀胱壁上就有组织学上分化的平滑肌细胞——直到冠臀长119毫米时，尿道平滑肌才能够区分出来。除了分化相对较晚外，尿道平滑肌在组织化学上也与膀胱逼尿肌不同。还观察到近端尿道平滑肌在排列和神经支配方面存在性别差异，这些发现支持了前列腺前尿道括约肌的存在。这种括约肌似乎主要起到防止射精时精液反流到膀胱的作用。
