摘要
用扫描电镜观察80例鸡胚咽弓的形态发生.鸡胚共有四对咽弓.第11期第一咽弓出现于心隆起颅侧胚体中部,然后向胚体两侧生长,发育成颜面的下颌隆起.至第17期鸡胚已出现四对咽弓.第二至第四咽弓出现于心隆起的两侧,然后向胚体中部生长.由此可见第一咽弓与其后各对咽弓的生长方向正好相反.第三和第四咽弓位于颈窦内,发育较差,至第25期被第二咽弓完全覆盖.第二咽弓覆盖颈窦时,并不与第三和第四咽弓融合,而似架桥一样跨越颈窦.
The morphogenesis of the visceral arches is studied using scanning electron microscopy in 80 chick embryos between stage 10～26.There are 4 pairs of visceral arches separated by grooves in the chick embryo.These viseral arches differentiate in a cephalo-caudal sequence and then are obliterated in reverse order.At stage 11 the 1st visceral arch begins to appear at point cranial to the heart bulge in the ventral middle part, and then develops toward the lateral side to form the maxilary process of the face.Until stage 17 the 4 pairs of the visceral arches all appear.The 2nd to 4th visceral arches all appear on the either side of the heart bulge and develop toward the ventral midline.Thus, the development of the 1st visceral arch and those of the other visceral arches are in the opposite direction.The 3rd and 4th visceral arches lie within the cervical sinus.The low edge of the 2nd visceral arch tends to overgrow and obliterate the cervical sinus and its constituent structures.But there is no evidence that the 2nd visceral arch fuses with the 3rd and 4th visceral arches.
关键词
鸡胚
咽弓
扫描电镜
visceral arch
chick embryo
scanning electron microscope
