User talk:Traceychung/sandbox

I have assigned myself to the article 'Polyspermy'. I plan on gathering more relevant information about this topic and putting them together in this article. I will be adding one or two images or diagrams to better explain the mechanism of how Polyspermy can occur and how it can be prevented. I will also add information on whether or not polyspermy is possible in humans and how this can be prevented. Here are a few sources that I think can give some important information relating to the topic of this article:

1. Iwao, Y. (2012). Egg activation in physiological polyspermy. Reproduction, 144(1), 11-22. 10.1530/REP-12-0104 2. Wang, W. H., Abeydeera, L. R., Prather, R. S., & Day, B. N. (1998). Morphologic comparison of ovulated and in vitro–matured porcine oocytes, with particular reference to polyspermy after in vitro fertilization. Molecular reproduction and development, 49(3), 308-316. 3. Hunter, R. H. F., & Leglise, P. C. (1971). Polyspermic fertilization following tubal surgery in pigs, with particular reference to the role of the isthmus. Journal of reproduction and fertility, 24(2), 233-246. 4. Gilbert SF. Developmental Biology. 6th edition. Sunderland (MA): Sinauer Associates; 2000. Gamete Fusion and the Prevention of Polyspermy. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10033/ Traceychung (talk) 04:06, 9 February 2018 (UTC)

Article Draft - Polyspermy
However, there are some cases, in which the egg normally accepts more than one sperm but only one out of the multiple sperms will actually fuse its nucleus with the nucleus of the egg. This in known as Physiological Polyspermy. Physiological polyspermy is actually present in some species, both vertebrates as well as invertebrates. There are some species that undergo physiological polyspermy for proper development of their offspring. Some of these animals include birds, ctenophora, reptiles and amphibians, just to name a few. Some vertebrates that are both amniote or anamniote, for example, urodele amphibians, cartilaginous fish, birds and reptiles, undergo physiological polyspermy because of the internal fertilization of their yolky eggs. A fertilizing sperm triggers egg activation by the induction of free calcium ion concentration in the cytoplasm of the egg. This induction plays a very critical role in both physiological polyspermy and monomeric polyspermy species. The rise in calcium causes activation of the egg as the egg will then be altered on both a biochemical and morphological level. In mammals as well as sea urchins, the sudden rise in calcium concentration occurs because of the influx of calcium ions within the egg. These calcium ions are responsible for the cortical granule reaction, these ions are also stored in the endoplasmic reticulum of the egg.



Unlike physiological polyspermy, monospermic fertilization deals with the analysis of the egg calcium waves as this is the typical reproduction process in all species. Species that undergo physiological polyspermy have polypoidy-preventing mechanisms that act inside the egg. This is quite different from the normal polyspermy block on the outside of the egg. However, polyspermy is impossible in human reproduction. The decline in the numbers of sperm that swims to the oviduct is one of two ways that prevents polyspermy in humans. The other mechanism is blocking of sperm in the fertilized egg. According to Developmental Biology Interactive, if an egg becomes fertilized by multiple sperms, then the embryo will gain various paternal centrioles. When this happens, there is a struggle for extra chromosomes. This competition causes disarrayment in cleavage furrow formation and the consequence is death of the zygote.

Traceychung (talk) 14:56, 24 February 2018 (UTC)