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In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell ( spermatozoon ). [ 1 ]
At the end of the second week of development, some cells of the trophoblast penetrate and form rounded columns into the syncytiotrophoblast. These columns are known as primary villi. At the same time, other migrating cells form into the exocoelomic cavity a new cavity named the secondary or definitive yolk sac, smaller than the primitive yolk sac.
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism.
The Spemann–Mangold organizer is a group of cells that are responsible for the induction of the neural tissues during development in amphibian embryos.First described in 1924 by Hans Spemann and Hilde Mangold, the introduction of the organizer provided evidence that the fate of cells can be influenced by factors from other cell populations. [1]
Developmental Cell is a peer-reviewed scientific journal of cell and developmental biology. The journal was established in 2001, and is edited by Julie Sollier . It published by Cell Press , an imprint of Elsevier , and its articles becomes open access after an embargo period of one year.
Red cells depict presumptive endodermal cells, and blue cells depict presumptive ectodermal cells. Changes in the adhesion properties of these cells are the best characterized and understood mechanism of ingression. [3] In sea urchins, epithelial cells adhere to one another as well as the hyaline layer through classic cadherins and adherens ...
During embryogenesis, for a number of cell cleavages (the specific number depends on the type of organism) all the cells of an embryo will be morphologically and developmentally equivalent. This means, each cell has the same development potential and all cells are essentially interchangeable, thus establishing an equivalence group. The ...
In terms of developmental commitment, a cell can either be specified or it can be determined. Specification is the first stage in differentiation. [2] A cell that is specified can have its commitment reversed while the determined state is irreversible. [3] There are two main types of specification: autonomous and conditional.