The maturation stage is assisted by the maturation or meiotic division

March 20, 2019 0 Comment

The maturation stage is assisted by the maturation or meiotic division (Browder, 1985). The maturation division of the primary oocyte varies dramatically from the maturation division of the spermatocyte (Browder, 1985). After this the meiotic division of the nucleus and the cytoplasm of the oocyte, divides unevenly to shape a single big haploid oocyte and three little haploid polar bodies or polocytes near the end (Browder, 1985). If equal division was to happen to the primary oocyte the stored food volume would result in being given to the four daughter cells, this may affect the development of the embryo by being inadequate (Browder, 1985). As a result, these unequal divisions grant one out of the four daughter cells to accommodate the majority of the cytoplasm, whilst reserving food which is adequate for the developing embryo (Browder, 1985). The homologous chromosomes of the primary oocyte nucleus travel through the pairing or synapsis, duplication, chiasma development and crossing over, this occurs within the first maturation division or first meiosis I (Browder, 1985). Next due to contraction of the chromonemal fibres the nuclear membrane splits and the bivalent chromosomes travel in the direction of the opposite poles (Browder, 1985). The endoplasmic reticulum forms a new nuclear envelope around the daughter chromosome (Browder, 1985). Once karyokinesis has done its job the unequal cytokinesis takes place, resulting in a small haploid polar body or polocyte, along with a big haploid, secondary oocyte or ootid are produced (Browder, 1985).
Meiosis II is the Second meiotic division (Browder, 1985). Travelling through this meiosis II phase is the haploid secondary oocyte together with the first polocyte (Browder, 1985). As a result of the Meiosis II, the secondary oocyte forms a mature oocyte and a second polocyte (Browder, 1985). By the meiosis II stage the first polocyte additionally divides into two secondary polocytes (Browder, 1985). These polocyte then overflow out of the oocyte and deteriorate, meanwhile the haploid oocyte is then ready got the fertilisation (Browder, 1985).