NATS 1690 Lecture Notes - Lecture 30: Seminiferous Tubule, Spermatid, Spermatogenesis
1 Apr 2016
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We as individuals have 46 chromosomes (2n: when we go through meiosis, one parent has 23 chromosomes (n) , and the other has. 23 chromosomes (n: mitosis is just replenishing our cells. Gamete formaion gametogenesis: formaion of gamete = meiosis. Oogenesis: forming egg cells: males: produces four haploid spermaids, females: produces cells of diferent sizes. The secondary oocyte gets most of the cytoplasm and matures into egg. The 4 haploid cells produced from meiosis are sperm cells. Spermatogenesis (46 chromosomes) -> meiosis (primary spermatocyte, 2n 46 chromosome) -> Meiosis 11 ( secondary spermocytes, haploid 23 chromosome) -> cytomplasmic division (spermaids, haploid 23 chromosomes) Of the sperm contain one x chromosome and the other half is a y chromosome. Stages of oogenesis: growth stage: oogonia (diploid, meiosis 1: primary oocyte (diploid, meiosis 11: first polar bodies (haploid, cytoplasmic division: three polar bodies degenerates(haploid). Ferilizaion restores the diploid condiions by combining two haploid sets of chromosome in zygote.
