BIOB33H3 Lecture Notes - Lecture 3: Lipid Bilayer Fusion, Metaphase, Fetus
Document Summary
Development can be characterized by different periods of time. Involves embryology prenatal development focussing on the first two months after fertilization. Postnatal development development from birth to maturity. Fertilization is the joining of two haploid cells to create a diploid cell. Ovum: outermost layer has loosely defined cells called corona radiata (protective layer, deep to corona radiata is another protective layer the jelly-like zona pellucida, contains a polar body which is a non-functioning cell that eventually degrades. Provides the maternal chromosomes (secondary oocyte that has 23 haploid chromosomes, 22 autosomes and a second x chromosome, suspended in metaphase of meiosis ii) Fertilization occurs in the ampulla of the uterine tube. 200 million sperm cells enter the vaginal canal. Only about 10,000 make it to the uterine tubes. Oocyte at ovulation: ovulation releases a secondary oocyte and the first polar body; both are surrounded by the corona radiata, which protects the egg.
