Tag Archives | Embryology

Envelopes of the Egg | Animals | Gametogenesis | Embryology

All eggs, like any other cells, are of course covered by the cell membrane or plasmalemma. Under the electron microscope the plasmalemma sometimes can be seen to be double, with two layers of electron-dense material about 50 Å thick separated by a less dense interval of about 60 Å. In addition to the plasmalemma, eggs of all animals, with the [...]

By |2018-04-30T10:44:14+00:00April 30, 2018|Gametogenesis|Comments Off on Envelopes of the Egg | Animals | Gametogenesis | Embryology

Parental Genes and Embryos | Gastrulation | Embryology

In this article we will discuss about the involvement of parental genes in the development of control of embryos. Apart from the foregoing data, which characterize the activity of the nuclear DNA in general terms, there are many indirect indications that nuclear genetic factors (the genes), after having been dormant throughout the period of cleavage, begin to manifest themselves during [...]

By |2018-04-30T10:44:14+00:00April 30, 2018|Gastrulation|Comments Off on Parental Genes and Embryos | Gastrulation | Embryology

Growth of the Oocyte | Oogenesis | Gametogenesis | Embryology

In the female sex the first stage of the development of gametes is similar to that found in spermatogenesis – the oogonia—the cells eventually giving rise to the eggs— undergo proliferation by mitotic divisions. They then become oocytes and enter a peri­od of growth. Owing to the fact that the egg contributes the greater part of the sub­stances used in [...]

By |2018-04-30T10:44:14+00:00April 30, 2018|Oogenesis|Comments Off on Growth of the Oocyte | Oogenesis | Gametogenesis | Embryology
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