ectoderm /ec·to·derm/ (ek´to-derm) the outermost of the three primitive germ layers of the embryo; from it are derived the epidermis and epidermic tissues, such as the nails, hair, and glands of the skin, the nervous system, external sense organs and mucous membrane of the mouth and anus.ectoder´malectoder´mic
ectoderm
ectoderm
ec·to·derm ( k t -dûrm )n. The outermost of the three primary germ layers of an embryo, from which the epidermis, nervous tissue, and sense organs develop. Also called ectoblast. ec to·dermal, ecto·dermic adj. |
ectoderm
[ek′tədurm]
Etymology: Gk, ektos, outside, derma, skin
the outermost of the three primary cell layers of an embryo. The ectoderm gives rise to the nervous system; the organs of special sense, such as the eyes and ears; the epidermis and epidermal tissue, such as fingernails, hair, and skin glands; and the mucous membranes of the mouth and anus. See also embryo, endoderm, mesoderm. ectodermal, ectodermic, adj.
ectoderm
(ek´t
durm),
n the outermost of the three primary cell layers of an embryo. The ectoderm gives rise to the nervous system, the organs of special sense, the epidermis, and epidermal tissues such as fingernails, hair, and skin glands.
durm), n the outermost of the three primary cell layers of an embryo. The ectoderm gives rise to the nervous system, the organs of special sense, the epidermis, and epidermal tissues such as fingernails, hair, and skin glands.
ectoderm
the outermost of the three primitive germ layers of the embryo; from it are derived the epidermis and epidermal derivatives, such as the claws, hair and glands of the skin, the nervous system, external sense organs (eye, ear, etc.) and mucous membrane of the mouth and anus.
ectoderm
The outermost of the three primary germinal layers of an embryo (the other layers being mesoderm and endoderm) from which the eye is derived. It differentiates into outer surface ectoderm and inner neuroectoderm, which gives rise to neural crest cells. The surface ectoderm gives rise to the crystalline lens, the lacrimal gland, the meibomian glands, the corneal and conjunctival epithelium and the epidermis of the eyelids. The neuroectoderm (neural ectoderm) will form the retina, retinal pigment epithelium, the pigmented and non-pigmented layers of the ciliary and iris epithelium, the dilator and sphincter muscles of the iris and the optic nerve fibres. Neural crest cells will form the corneal stroma and endothelium, sclera, iris and choroidal stroma, ciliary muscle and trabecular meshwork. See optic cup; mesoderm; optic vesicles.
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