ec·to·derm

(ĕk′tə-dûrm′)

1. The outermost of the three primary germ layers of an embryo, from which the epidermis, nervous tissue, and, in vertebrates, sense organs develop.

2. The outer layer of a diploblastic animal, such as a jellyfish.

ec′to·der′mal, ec′to·der′mic adj.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

ectoderm

(ˈɛktəʊˌdɜːm) or

exoderm

(Biology) the outer germ layer of an animal embryo, which gives rise to epidermis and nervous tissue. See also mesoderm, endoderm

ˌectoˈdermal, ˌectoˈdermic adj

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

ec•to•derm

(ˈɛk təˌdɜrm)

n.

the outer germ layer in the embryo of a metazoan.

[1860–65]

ec`to•der′mal, ec`to•der′mic, adj.

ec`to•der•moi′dal (-dərˈmɔɪd l) adj.

ectoderm

An embryo’s outer germ layer, which develops into structures including the brain and skin. See endoderm,mesoderm

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun

ectoderm - the outer germ layer that develops into skin and nervous tissue

ectoblast, exoderm

germ layer - (embryology) any of the 3 layers of cells differentiated in embryos following gastrulation

neural tube - a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop

Translations

ectoderma

ec·to·derm

n. ectodermo, la capa más externa del embrión.

English-Spanish Medical Dictionary © Farlex 2012

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References in periodicals archive

The shape of the aboral and oral ectoderm and the ciliary band that comprise the ADL, particularly in relation to the distribution and orientation of putative sensory cells therein, evokes a functional morphological explanation.

Sniffing out new data and hypotheses on the form, function, and evolution of the echinopluteus post-oral vibratile lobe

The resulting bucconasal membrane, consisting of a layer each of ectoderm and endoderm, separates the two compartments.

Schneiderian papilloma of the nasopharynx. (Original Article)

No one has yet been able to induce the cells to form the three distinct germ layers, in the correct order: endoderm on the inside, mesoderm in the middle and ectoderm on the outside.

Stem cells precisely manipulated toward first step in differentiation

(3) During the 3-5 weeks of gestational age neurulation occurs during which formation of the neural groove, closure of the anterior (25 days) and posterior (27 to 28 days) neuropores, appearance of the ventral horn cells, formation of anterior and posterior roots and disjunction of the neuroectoderm from the surface ectoderm takes place.

A rare case of lumbocostovertebral syndrome with spinal dysraphism and tethered cord

The cell bodies of the diffuse nervous system of the larva lie in the apical plate and around the ciliated band that borders the oral ectoderm. Axons extend beneath the ciliated bands and to the muscles derived from the coeloms (Lacalli and West, 1993).

The sea urchin genome as a window on function

Teratomas are primary congenital tumors made up of tissue that arises from all three embryonic germ cell layers: the ectoderm, the endoderm, and the mesoderm (although there have been reports of tumors made up of only bidermal ingredients).

Mature teratoma of the nasal vestibule: A case report

The pluripotent cells of the embryo organize themselves at an early stage in germ layers: the endoderm, mesoderm and ectoderm.

Researchers shed light on molecular underpinnings of creating insulin-producing beta cells

They are usually unilateral, unilocular, smooth- surfaced lesions filled with fatty material, containing tissues from all three embryonic layers- endoderm, mesoderm and ectoderm.

Wandering dermoid cyst of ovary causing obstructed labour--a case report

This specification occurs at the end of gastrulation, when the region that will form the future neural crest encompasses the border strip of the embryonic ectoderm and is situated at the interface between the neural and adjacent non-neural territories.

Insights from a sea lamprey into the evolution of neural crest gene regulatory network

The tongue comprises two parts that have different embryologic origins; the anterior two-thirds of the tongue arise from the ectoderm and the posterior one-third from the endoderm.

Intralingual dermoid cysts: A report of two new cases

These totipotent cells can differentiate into tissue components representing derivatives of mesoderm, ectoderm and endoderm.

Primary extragonadal mixed mesenchymal retroperitoneal tumours in post partum women presenting as 22 weeks of gestation

At 24 h, the assays were scored as fusions if the polyps fused to create a single gastric cavity and common ectoderm, or as rejections if they fell apart.

A test for larval kin aggregations