part of part_of develops from endoderm 内胚层 endoderm of foregut 前肠内胚层 digestive tract epithelium 消化道上皮 upper respiratory tract epithelium 上呼吸道上皮 embryonic tissue 胚胎组织 pharyngeal arch system 咽弓系统 entire pharyngeal arch endoderm 整个咽弓内胚层 pharyngeal arch endoderm 咽弓内胚层