BIOL-2230 Lecture Notes - Lecture 5: Corona Radiata, Ovarian Follicle, Folliculogenesis
Document Summary
Diploid oogonia undergo mitosis to produce primary oocytes: incorporate follicular cells to become primordial follicles. Primary oocytes start, but do not complete, meiosis i: they stop at prophase i. **females are born with the number of oocytes they will have their whole life. Meiosis i completes and produces the first polar body (very small cell) and a secondary oocyte that has almost all of the cytoplasm and most organelles. First polar body undergoes meiosis ii and produces two polar bodies. Secondary oocyte begins meiosis ii, but stops at metaphase ii. If fertilized: secondary oocyte completes meiosis ii, produces large ovum and tiny polar body. If no fertilization occurs: secondary oocyte degenerates. Monthly cycle of events involved with ovum maturation. Has 2 parts or cycles that are linked with ovulation occurring in the middle: first cycle is the follicular phase, then ovulation, then the luteal phase.