6.6a Female Hormones
11/03/2013 § Leave a comment
This next unit will start off as review of what we learned in middle school and in ninth grade. Let’s start from the very top with the female reproductive system. Okay, so an embryo in its mother’s wound can develop into a male or a female fetus. If the tdf gene is present, the baby develops into a male. If it isn’t there (usually it’s on the Y-chromosome), then the baby will probably become a female, but I’m assuming there are some rare cases. The embryonic gonads would then develop into ovaries (instead of testes), along with the production of the two female hormones – estrogen and progesterone, which are always present during pregnancy. These two hormones trigger the development of the female genitalia. Note: We’ve been talking about humans this whole time, excuse me.
What we learned in middle school and ninth grade was the menstrual cycle, but here, we take a look at the hormonal control of the menstrual cycle. Human females can reproduce at any give time of the year because of the production of the eggs in follicles, which are fluid-filled sacs. The endometrium – the lining of the uterus – thickens in preparation for the implantation of the embryo. If, when the follicle releases an egg, and fertilization doesn’t occur, then the released egg (called the corpus luteum) breaks down in the process of menstruation.
Over the period of a menstrual cycle, the hormone levels in a human female change. The ovary and endometrium are what endures the most change. The first half is called the follicular phase, because it’s when the follicle develops. The second half is called the luteal phase, because it’s the period where the corpus luteum develops.
There are so many essay questions for this unit, I could cry.
- Draw a labelled diagram of the adult female reproductive system. 4 marks
- Draw a labeled diagram of an adult male reproductive system. 6 marks
- Explain the processes involved in oogenesis in humans. 9 marks
- Draw the structure of a mature human egg. 4 marks
- Explain the role of hormones in the regulation of the menstrual cycle in human females. 8 marks
- Outline the levels of each of the hormones that control the menstrual cycle immediately before ovulation. 3 marks
- Explain the roles of LH and FSH in the menstrual cycle, including the timing of their secretion during the cycle. 6 marks
- Outline the roles of progesterone and estrogen in the human menstrual cycle. 6 marks
- Draw a labeled diagram of the structure of an ovary as seen using a light microscope. 5 marks
- Draw the structure of the human female reproductive system immediately before ovulation. (Only the ovaries, oviducts and uterus need to be shown.)6 marks
- Draw a labelled diagram of a mature sperm. 5 marks
- Outline the process of spermatogenesis in humans. 5 marks
- Production of semen involves a series of processes, which in total take many weeks to carry out. Outline the processes involved in semen production from the start of sperm formation (spermatogenesis) to ejaculation. 8 marks
- Compare the process of spermatogenesis and oogenesis. 7 marks
- Discuss how, in humans, a larger number of sperms are produced than eggs. 4 marks
- Describe the process of fertilization in humans. 8 marks
- Describe the development of the early human embryo. 5 marks
- Outline the regulation of pregnancy by two named hormones. 4 marks
- Outline the role of human chorionic gonadotropin (HCG) in early pregnancy 2 marks
- Outline the way in which a pregnancy can be detected at a very early stage. 4 marks
- Compare the roles of LH and HCG in female reproduction. 2 marks
- State the role of the amniotic sac and the amniotic fluid. 2 marks
- Explain the function and structure of the placenta. 8 marks
- Outline the process of in vitro fertilization (IVF). 6 marks
- Discuss the ethical issues surrounding IVF. 6 marks
- Outline the role of positive feedback in the process of birth in humans. 4 marks
DATA BASED QUESTIONS
Page 272, the female athlete triad
- a) Outline the relationship between number of menstrual cycle per year and bone density. —> Women with 11 – 13 menstrual cycles per year tend to have more standard deviations above the mean peak bone mass than women with less than 11 menstrual cycles per year. All of the women with 0 – 3 menstrual cycles per year were below the peak bone mass. In the neck of femur, women with 4 – 10 menstrual cycles per year were below the peak bone mass, but in the trochanter of femur, women with 4- 10 cycles per year were just slightly above the peak bone mass.
- b) Compare the results for the neck of the femur with the results for the trochanter. Women with 0 – 3 cycles per year show the same results in both the femur and trochanter – below the peak bone mass. Women with 11 – 13 menstrual cycles per year also both showed standard deviations above the peak bone mass. Women with 4 – 10 menstrual cycles in the neck of femur were below the peak bone mass but in the trochanter, were slightly higher than the peak bone mass.
2. Explain the reasons for some of the runners having:
- a) higher bone density than the mean —> the women are producing the hormones that strengthen bone density
- b) lower bone density than the mean —> no estrogen; women with 0 – 3 menstrual cycles per year don’t produce enough estrogen and if they don’t have osteoporosis nor do they consume enough calcium, vitamin D or energy, then they would have lower bone density than the mean.
- a) Suggest reasons for female athletes having few or no menstrual cycles. —> Every female’s menstrual cycles are different, and it also relies on their age (the older the female athlete gets, the less frequent the cycles). Also, if there is no estrogen in the female’s body, part of ovulation can’t be completed anyway.
- b) Suggest one reason for eating disorders and low body weight in female athletes. —> They want to keep their figure; they want to stop their menstrual cycles so they don’t have to worry about it during their sport.