Induced Pluripotent Stem Cells

Polar Body Formation Extrusion and Function

Regen Center Glossary

The Polar body refers to the resultant structure that an egg cell (oogonium) produces as it undergoes meiosis. During the first stage of meiosis, the egg cell evenly divides the chromosomes between the resultant two cells. However, the cytoplasm is divided unevenly.


One of the cells retains majority of the cytoplasm, leaving the other cell with a very small amount or nearly none. That smaller cell represents the first polar body, which normally undergoes degeneration. The resultant larger cell, which is the ovum, re-divides, generating the second polar body containing half of the chromosome amount and a nearly absent cytoplasm. This second polar body then splits up and positions itself near the oocyte or the larger cell until such time that it undergoes degeneration. At the end of meiosis, there shall be only one functional egg or oocyte produced.

Oocyte Polar Body Biopsy Video

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