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The surface ectoderm, AKA external ectoderm, is one of the two early embryonic divisions of the ectoderm. The other early division of the ectoderm is the neuroectoderm. The surface ectoderm develops into the following structures: Skin (only the epidermis; the dermis is derived from the mesoderm) (along with glands, hair, and nails)
The position of the ectoderm relative to the other germ layers of the embryo is governed by "selective affinity", meaning that the inner surface of the ectoderm has a strong (positive) affinity for the mesoderm, and a weak (negative) affinity for the endoderm layer. [6] This selective affinity changes during different stages of development.
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The ectoderm generates the outer layer of the embryo, and it forms from the embryo's epiblast. [13] The ectoderm develops into the surface ectoderm, neural crest, and the neural tube. [14] The surface ectoderm develops into: epidermis, hair, nails, lens of the eye, sebaceous glands, cornea, tooth enamel, the epithelium of the mouth and nose.
Surface ectoderm forms the lens, corneal epithelium and eyelid. The extracellular mesenchyme forms the sclera , the corneal endothelium and stroma , blood vessels , muscles , and vitreous . The eye begins to develop as a pair of optic vesicles on each side of the forebrain at the end of the fourth week of pregnancy.
The ectoderm is the start of a tissue that covers the body surfaces. It emerges first and forms from the outermost of the germ layers. Production The ...
The germ layers are referred to as the ectoderm, mesoderm and endoderm. In diploblastic animals only the ectoderm and the endoderm are present. [8] * Among different animals, different combinations of the following processes occur to place the cells in the interior of the embryo: Epiboly – expansion of one cell sheet over other cells [9]
The cells of the primitive node secrete many cellular signals essential for neural differentiation. After gastrulation the developing embryo is divided into ectoderm, mesoderm, and endoderm. The ectoderm gives rise to epithelial and neural tissue, with neural tissue being the default cell fate.