part of part_of anatomical cluster 解剖簇 embryo 胚胎 pharyngeal arch system 咽弓系统 A transient embryonic complex that comprises the pharyngeal arches, bulges of tissues of mesoderm and neural crest derivation through which pass nerves and pharyngeal arch arteries. The arches are separated internally by pharyngeal pouches, evaginations of foregut endoderm, and externally by pharyngeal clefts, invaginations of surface ectoderm. The development of the system ends when the stucture it contributes to are forming, which may include (depending on species) the thymus, thyroid, parathyroids, maxilla, mandible, aortic arch, cardiac outflow tract, external and middle ear[GO,modified]. pharyngeal apparatus pharyngeal arch region pharyngeal arches and clefts pharyngeal system 一个短暂的胚胎复合体，包括咽弓，中胚层组织和神经嵴衍生的凸起，而这些神经嵴衍生通过神经和咽弓动脉。拱内部由咽囊，前肠内胚层外翻分开，外部由咽裂，外表面内胚层内陷分开。系统的发展在它所促成的结构形成时就结束了，这些结构可能包括（取决于物种）胸腺、甲状腺、甲状旁腺、上颌骨、下颌骨、主动脉弓、心脏流出道、外耳和中耳[GO，修改] 。 咽器 咽弓区 咽弓和裂 咽系统 pharyngeal region of foregut 前肠咽部