Gatal'skiĭ V V
Vestn Otorinolaringol. 2005(3):25-8.
Physiological atresia, or fetal occlusion, is an epithelial vegetation arising at a certain stage of embryonal fetal life in some organs of esophageal, respiratory and urogenital system as well as in natural openings of the head--the lid slit, external nasal openings, external and internal acoustic meatus. In parallel, tubal organs close to open later, i.e. recanalization takes place. In view of this, epithelial "plugs" in the larynx and external nasal openings have a positive biological role making a temporary obstruction for amniotic fluid penetration into the viscera. Plug-induced difference of pressure between closed nasal cavity and open oral cavity in reflexes of mouth opening helps horizontal adjustment of the processes of the palate bone. This is important for formation of the hard palate. Before appearance of functioning muscles of the soft palate, epithelial plugs in the external nasal openings block nasal cavity. If the plugs were absent, fetal swallowing movement would be impossible, as amniotic fluid would outpour through the nose. Epithelial adhesions in external nasal openings as well as in the larynx and esophagus are temporary structures contributing to formation of palatine shape and establishment of fetal functions.
生理性闭锁，或胎儿期阻塞，是指在胚胎胎儿期的某个阶段，在食管、呼吸系统和泌尿生殖系统的某些器官以及头部的自然开口——睑裂、鼻外孔、外耳道和内耳道中出现的上皮性赘生物。与此同时，与之相连的管道器官随后会重新开放，即发生再通。鉴于此，喉和鼻外孔中的上皮“栓子”具有积极的生物学作用，可暂时阻止羊水渗入内脏。在张口反射中，由栓子导致的封闭鼻腔和开放口腔之间的压力差有助于腭骨发育过程的水平调节。这对硬腭的形成很重要。在软腭功能肌肉出现之前，鼻外孔中的上皮栓子会阻塞鼻腔。如果没有这些栓子，胎儿的吞咽动作将无法进行，因为羊水会从鼻子流出。鼻外孔以及喉和食管中的上皮粘连是临时性结构，有助于腭部形态的形成和胎儿功能的建立。
