11. Reproduction Explain the meaning of each of the following: 1. Implantation: __ 2. Fertilization: __ 3. Menstruation: __ 4. Ovulation: __ 5. Menopause: __ Short Answer 12. What is a chorion? 13. What is the importance of human chorionic gonadotropic hormone? 14. In the blastocyst, what does the ectoderm layer (outer layer) later form? 15. What are the possible effects of amniocentesis on the unborn child? 16. If a doctor wanted to induce labour in a pregnant woman what hormone could be injected? 17 List five general points that describe the 28-30 day menstruation cycle and indicate when during the cycle the woman is most fertile.

### Definitions<br /><br />1. **Implantation:**<br /> Implantation is the process by which a fertilized egg (blastocyst) attaches itself to the lining of the uterus (endometrium) to begin pregnancy. This typically occurs about 6-10 days after fertilization.<br /><br />2. **Fertilization:**<br /> Fertilization is the union of a male sperm cell with a female egg cell, resulting in the formation of a zygote. This usually takes place in the fallopian tube.<br /><br />3. **Menstruation:**<br /> Menstruation is the monthly shedding of the uterine lining (endometrium) when pregnancy does not occur. It results in bleeding through the vagina and typically lasts between 3-7 days.<br /><br />4. **Ovulation:**<br /> Ovulation is the release of an egg from one of the ovaries. This usually occurs around the middle of the menstrual cycle, approximately 14 days before the start of the next period.<br /><br />5. **Menopause:**<br /> Menopause is the time in a woman's life when her menstrual periods permanently stop, marking the end of her reproductive years. It is diagnosed after 12 consecutive months without a menstrual period.<br /><br />### Short Answers<br /><br />12. **What is a chorion?**<br /> The chorion is the outermost membrane surrounding an embryo in mammals, birds, and reptiles. In humans, it contributes to the formation of the placenta.<br /><br />13. **What is the importance of human chorionic gonadotropic hormone?**<br /> Human chorionic gonadotropic hormone (hCG) is crucial for maintaining the corpus luteum during early pregnancy, which in turn produces progesterone to sustain the uterine lining and support the developing embryo.<br /><br />14. **In the blastocyst, what does the ectoderm layer (outer layer) later form?**<br /> The ectoderm layer of the blastocyst later forms structures such as the skin, hair, nails, and the nervous system, including the brain and spinal cord.<br /><br />15. **What are the possible effects of amniocentesis on the unborn child?**<br /> Amniocentesis can carry risks such as miscarriage, needle injury, infection, or leakage of amniotic fluid. However, these risks are relatively low when the procedure is performed by experienced practitioners.<br /><br />16. **If a doctor wanted to induce labour in a pregnant woman what hormone could be injected?**<br /> A doctor could inject oxytocin to induce labor. Oxytocin stimulates uterine contractions and helps progress labor.<br /><br />17. **List five general points that describe the 28-30 day menstruation cycle and indicate when during the cycle the woman is most fertile.**<br /> - **Menstrual Phase (Days 1-5):** Shedding of the uterine lining, resulting in menstrual bleeding.<br /> - **Follicular Phase (Days 1-13):** The pituitary gland releases follicle-stimulating hormone (FSH), which stimulates the growth of ovarian follicles.<br /> - **Ovulation (Day 14):** Release of a mature egg from the ovary, triggered by a surge in luteinizing hormone (LH). This is the most fertile period.<br /> - **Luteal Phase (Days 15-28):** The ruptured follicle transforms into the corpus luteum, which secretes progesterone to prepare the uterine lining for potential implantation.<br /> - **Premenstrual Phase (Days 25-28):** If fertilization does not occur, the corpus luteum degenerates, leading to a drop in progesterone and estrogen levels, and the cycle begins anew with menstruation.<br /><br />The woman is most fertile around the time of ovulation, typically between days 12-16 of the cycle.