n.外胚层，外层

The ectoderm gives rise to the skin, hair, nails, sweat glands, and teeth.
外胚层发育形成皮肤、毛发、指甲、汗腺和牙齿。
In vertebrates, the neural tube develops from the ectoderm.
在脊椎动物中，神经管由外胚层发育而来。
The early embryo is composed of three germ layers: the endoderm, mesoderm, and ectoderm.
早期胚胎由三层原胚层构成：内胚层、中胚层和外胚层。
The outer layer of the developing embryo, known as the ectoderm, will eventually become the nervous system and the epidermis.
发育中的胚胎最外层，称为外胚层，最终将发展成为神经系统和表皮。
Ectodermal dysplasia is a group of rare genetic disorders affecting the development of structures derived from the ectoderm.
外胚层发育不全是一组影响源自外胚层结构发育的罕见遗传性疾病。
The formation of the sensory organs, such as eyes and ears, starts with the differentiation of specialized cells in the ectoderm.
感官器官如眼睛和耳朵的形成始于外胚层中特化细胞的分化。
In frogs, the amphibian tadpole's tailfin is derived from the ectoderm.
在青蛙等两栖类蝌蚪中，尾鳍是由外胚层发育而来的。
Certain types of cancer, like melanoma, originate from the ectodermal tissue.
某些类型的癌症，如黑色素瘤，起源于外胚层组织。
During embryonic development, the ectoderm forms the epithelial coverings of all body surfaces.
在胚胎发育过程中，外胚层形成了身体所有表面的上皮覆盖物。
The placenta, although not part of the fetus itself, has tissues that derive from both the mother's and the embryo's ectoderm.
胎盘虽然不是胎儿的一部分，但它包含来源于母体和胚胎外胚层的组织。