THE STRUCTURE AND DEVELOPMENT OF THE PALATE IN ALLIGATOR-MISSISSIPPIENSIS
THE STRUCTURE AND DEVELOPMENT OF THE PALATE IN ALLIGATOR-MISSISSIPPIENSIS
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DOI：
10.1016/0003-9969(81)90041-8
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发表时间：
1981-01-01
影响因子：
3
通讯作者：
FERGUSON, MWJ
中科院分区：
文献类型：
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作者：
FERGUSON, MWJ
鳄鱼是唯一拥有真正的哺乳动物般的次级腭并在卵中发育的动物，但在这些古老的爬行动物中没有研究腭发育;甚至成年形态也鲜为人知。本文对A.对126只已知年龄的胎儿、20只孵化的幼仔和41只已知年龄的成体进行了肉眼和显微镜检查。腭由前颌骨、上颌骨、腭骨和翼骨组成，无软腭。腭粘膜分为许多低乳头，每个乳头都有一个专门的触觉感受器。胚胎的次级腭架从第一次出现开始水平生长，这可能与发育不良，低卧的舌头和口鼻腔中可用的空间量有关。在胚胎和成体中没有内在的舌肌肉组织。舌头由外部肌肉组织和大量脂肪组成。腭板闭合从前向后迅速进行：2个搁板尖端的上皮细胞通过合并而不是上皮融合和细胞死亡而分散。鼻咽管在前部由腭架与颅底的向下生长物融合而产生，以产生分隔的导管;在后部，腭架本身的融合产生未分隔的导管，其随后被导管生长物分开。扬子鳄胚胎是研究腭形成发育机制的一个有用模型。
The crocodilians are the only animals which possess a true mammal-like secondary palate and develop in an egg, but palatogenesis was not studied in these ancient reptiles; even the adult morphology is little known. The structure and development of the palate in A. mississippiensis was investigated macroscopically and microscopically in 126 age-known fetuses, 20 hatchlings and 41 age-known adults. The palate consists of the premaxillae, maxillae, palatines and pterygoids with no soft palate. The palatal mucosa is thrown into numerous low papillae, each containing a specialized tactile receptor. The embryonic secondary palatal shelves grow horizontally from their 1st appearance which may be related to the poorly developed, low-lying tongue and the amount of space available in the oronasal cavity at this stage of development. An intrinsic tongue musculature is absent in the embryo and adult. The tongue consists of the extrinsic musculature plus a large mass of fat. Palate closure proceeds rapidly from before backwards: the epithelial cells of the tips of the 2 shelves disperse by merging rather than by epithelial fusion and cell death. The nasopharyngeal duct arises anteriorly by fusion of the palatal shelves with a downgrowth from the skull base to produce a partitioned duct; posteriorly, fusion of the shelves themselves produces an unpartitioned duct which is subsequently divided by ductal outgrowths. The alligator fetus is evidently a useful model for investigating developmental mechanisms in palate formation.