Search results
Results from the WOW.Com Content Network
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals the blastocyst, is reorganized into a two-layered or three-layered embryo known as the gastrula. [1]
The cells continue to be rearranged until the shallow dip formed by invagination transforms into a deeper, narrower pouch formed by the gastrula's endoderm. This pouch narrows and lengthens to become the archenteron, a process driven by convergent extension. The open end of the archenteron is called the blastopore.
This dent, the blastopore, deepens to become the archenteron, the first phase in the growth of the gut. In deuterostomes , the original dent becomes the anus, while the gut eventually tunnels through the embryo until it reaches the other side, forming an opening that becomes the mouth. [ 1 ]
The Gastruloid model system draws its origins from work by Marikawa et al.. [4] In that study, small numbers of mouse P19 embryonal carcinoma (EC) cells, were aggregated as embryoid bodies (EBs) and used to model and investigate the processes involved in anteroposterior polarity and the formation of a primitive streak region. [4]
Before gastrulation, the cells of the trophoblast become differentiated into two layers: The outer layer forms a syncytium (i.e., a layer of protoplasm studded with nuclei, but showing no evidence of subdivision into cells), termed the syncytiotrophoblast, while the inner layer, the cytotrophoblast, consists of well-defined cells.
Endoderm is the innermost of the three primary germ layers in the very early embryo.The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). [1] Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm.
The cells of the epiblast move toward the primitive streak and slip beneath it, in a process called "invagination". Some of the migrating cells displace the hypoblast and create the endoderm, and other cells migrate between the endoderm and the epiblast to create the mesoderm. The remaining cells form the ectoderm.
Epiboly in zebrafish is the first coordinated cell movement, beginning at the dome stage late in the blastula period and continuing throughout gastrulation. [3] At this point the zebrafish embryo contains three portions: an epithelial monolayer known as the enveloping layer (EVL), a yolk syncytial layer (YSL) which is a membrane-enclosed group of nuclei that lie on top of the yolk cell, and ...