BIOB33H3 Lecture Notes - Lecture 3: Gastrulation, Inner Cell Mass, Primitive Streak
Document Summary
Introduction: development involves, differentiation of cells, reorganization of cells, development can be characterized by different periods of time, prenatal development fertilization/conception to delivery, postnatal development development from birth to maturity. Involves embryology prenatal development focussing on the first two months after fertilization. 200 million sperm cells enter the vaginal canal: only about 10,000 make it to the uterine tubes, only one will fertilize the egg. Less than 100 actually contact the egg: fertilization details, oocyte at ovulation: ovulation releases a secondary oocyte and the first polar body; both are surrounded by the corona radiata, which protects the egg. The oocyte is suspended in metaphase of meiosis ii: fertilization and oocyte activation: acrosomal enzymes (hyaluronidase) from multiple sperm create gaps in the corona radiata. A single sperm then makes contact with the oocyte membrane, and membrane fusion occurs, triggering oocyte activation and. The chorion will eventually develop extensions into the endometrium.
