Epiboly



This picture was taken from the following website:
http://worms.zoology.wisc.edu/frogs/gast/epiboly.gif

During a fierce round of tic-tac-toe yesterday in class, I came across the word epiboly. I had first discovered the term in the textbook, but yesterday's discussion made me realize how important it is in Development Biology. The term is defined as "the movement of epithelial sheets (usually of ectodermal cells) that spread as a unit (rather than individually) to enclose the deeper layers of the embryo. Epiboly can occur by the cells dividing, by the cells changing their shape, or by several layers of cells intercalating into fewer layers. Often, all three mechanisms are used." Essentially, during epiboly, a sheet of cells spreads by thinning to cover the embryo.

The information referenced above was taken from the following reference: Gilbert, Scott F. "Early Development in Selected Invertebrates - Gastrulation." Developmental Biology. Vol. 9. Sunderland, MA: Sinauer Associates, 2010. 164. Print.