Exempel på ectoderm

• And only the epidermis, or outer layer of our skin, and the nervous system and parts of our sense-organs have arisen from the ectoderm. 

• In the first embryonic structure they are merely a pair of simple cutaneous glands, or depressions in the ectoderm. 

• In the normal development of the tadpole from the egg, as in all other vertebrate animals, the lens is formed from the outer skin or ectoderm of the head. 

• The outer envelope of dark smaller cells forms the ectoderm or skin-layer. 

• We find the first differentiation of epithelial and stinging cells, or of muscular and neural cells, in the thick ectoderm of the hydra. 

• By the 10-somite stage, there is strong staining in the lateral ectoderm and caudal dorsal neural tube.

• The chicken spalt4 gene (csal4) is expressed in the neural tube, migrating neural crest, branchial arches and, transiently, in the cranial ectoderm.

• Players remain pluripotential like stem cells, yet to make their way toward differentiation as infielders (mesoderm), outfielders (ectoderm), or pitchers or catchers (endoderm).

• The neural ectoderm thickens to become the neural plate, which invaginates to form the neural tube.

• They are formed by surface ectoderm and pharyngeal endoderm and are populated by paraxial mesoderm and cranial neural crest cells.

• During the next few days the outer surface of the embryo (or ectoderm) folds in upon itself to form the neural tube.

• During this complex developmental process, the outer embryonic ectoderm and its underlying mesoderm give rise to the epidermal and dermal components, which essentially build up the hair follicle unit.

• Presumptive neural crest cells initially lie in the neural folds at the juncture between the neural and non-neural ectoderm and then within the dorsal neural tube after its closure.

• At this point, there are two layers of cells - the ectoderm (outermost) and the endoderm (innermost) layers.

• It is not a teratoma, however, which is a neoplasm comprising all three germ cell layers (ectoderm, endoderm, mesoderm).

• This leads to the specification of non-neural ectoderm and later in the blastula stage to anmioserosa.

• Embryos have three layers: endoderm, mesoderm and ectoderm.

• Each structure originates form different germinative layers or tissues: the ectoderm, endoderm and mesenchyme.