World Library  
Flag as Inappropriate
Email this Article

Polarity in embryogenesis

Article Id: WHEBN0007327786
Reproduction Date:

Title: Polarity in embryogenesis  
Author: World Heritage Encyclopedia
Language: English
Subject: Ectoderm, Developmental biology, NovoGen, Polarity, Polarization
Collection: Developmental Biology
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Polarity in embryogenesis

An oocyte with poles depicted

In developmental biology, an embryo is divided into two hemispheres: the animal pole and the vegetal pole within a blastula.

The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. In some cases, the animal pole is thought to differentiate into the later embryo itself, forming the three primary germ layers and participating in gastrulation.

The vegetal pole contains large yolky cells that divide very slowly, in contrast with the animal pole above it. In some cases, the vegetal pole is thought to differentiate into the extraembryonic membranes that protect and nourish the developing embryo, such as the placenta in mammals and the chorion in birds.

The development of the animal-vegetal axis occurs prior to fertilisation.[1] Sperm entry can occur anywhere in the animal hemisphere.[2] The point of sperm entry defines the dorso-ventral axis - cells opposite the region of sperm entry will eventually form the dorsal portion of the body.[1][3]

In the frog


See also

  1. ^ a b Gilbert SF. Developmental Biology. 6th edition. Sunderland (MA): Sinauer Associates; 2000. Early Amphibian Development. Available from: http://www.ncbi.nlm.nih.gov/books/NBK10113/
  2. ^ Wolpert, Lewis; Tickle, Cheryll; Martinez Arias, Alfonso (2015). Principles of Development (5th ed.). Oxford University Press. p. 149. Retrieved 12 October 2015. 
  3. ^ Angerer, Lynne M.; Angerer, Robert C. (February 2000). "Animal–Vegetal Axis Patterning Mechanisms in the Early Sea Urchin Embryo". Developmental Biology 218 (1): 1–12.  
  4. ^ P. Hausen, M. Riebesell: The Early Embryonic Development of Xenopus Laevis - An Atlas of the Histology ISBN 3-921ö15-ö4-9

References

The animal pole draws its name from its liveliness relative to the slowly developing vegetal pole. Hence the vegetal pole is named for its relative inactivity relative to the animal pole.

Naming

[4]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.