Organogenesis

Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal organs of the organism.[1]

The endoderm of vertebrates produces tissue within the lungs, thyroid, and pancreas. The mesoderm aids in the production of cardiac muscle, skeletal muscle, smooth muscle, tissues within the kidneys, and red blood cells. The ectoderm produces tissues within the epidermis and aids in the formation of neurons within the brain, and melanocytes.

The cells of each of the three germ layers undergo differentiation, a process where less-specialized cells become more-specialized through the expression of a specific set of genes. Cell differentiation is driven by cell signaling cascades.[2] Differentiation is influenced by extracellular signals such as growth factors that are exchanged to adjacent cells which is called juxtracrine signaling or to neighboring cells over short distances which is called paracrine signaling.[3] Intracellular signals – a cell signaling itself (autocrine signaling) – also play a role in organ formation. These signaling pathways allow for cell rearrangement and ensure that organs form at specific sites within the organism.[1] The organogenesis process can be studied using embryos and organoids.[4]

  1. ^ a b Gilbert, S. F.; Barresi, M. J. F. (2017-05-01). "Developmental Biology, 11Th Edition 2016". American Journal of Medical Genetics Part A. 173 (5): 1430. doi:10.1002/ajmg.a.38166. ISSN 1552-4833.
  2. ^ Rankin, Scott (2018). "Timing is everything: Reiterative Wnt, BMP and RA signaling regulate developmental competence during endoderm organogenesis". Developmental Biology. 434 (1): 121–132. doi:10.1016/j.ydbio.2017.11.018. PMC 5785443. PMID 29217200 – via NCBI.
  3. ^ Edlund, Helena (July 2002). "Organogenesis: Pancreatic organogenesis — developmental mechanisms and implications for therapy". Nature Reviews Genetics. 3 (7): 524–532. doi:10.1038/nrg841. ISSN 1471-0064. PMID 12094230. S2CID 2436869.
  4. ^ Ader, Marius; Tanaka, Elly M (2014). "Modeling human development in 3D culture". Current Opinion in Cell Biology. 31: 23–28. doi:10.1016/j.ceb.2014.06.013. PMID 25033469.