Test Your Understanding
12 INTERPRET DATA Examine Figure 50-14. Which hormones are present in largest concentration just before ovulation? During which part of the menstrual cycle is the endometrium most prepared to receive an embryo? Which hormones stimulate thickening of the endometrium?
Gonadotropic hormones and ovarian hormones regulate the monthly sequence of events that take place within the ovary and uterus. The preovulatory phase begins with menstruation; the postovulatory phase begins after ovulation.
Figure 50-14 Endocrine regulation of the menstrual cycle When fertilization does not occur, the menstrual cycle repeats about every 28 days. Note the changes in hormone concentrations that regulate the menstrual cycle. (FSH, follicle-stimulating hormone; LH, luteinizing hormone)
PREDICT What happens when a. woman’s ovaries produce a very low amount of estrogen?
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Chapter 50 Solutions
Biology (MindTap Course List)
- Figure 43.17 Which of the following statements about the menstrual cycle is false? Progesterone levels rise during the luteal phase of the ovarian cycle and the secretory phase of the uterine cycle. Menstruation occurs just after LH and FSH levels peak. Menstruation occurs after progesterone levels drop. Estrogen levels rise before ovulation, while progesterone levels rise after.arrow_forwardWatch this series of videos (http://openstaxcollege.org/l/oocyte) to look at the movement of the oocyte through the ovary. The cilia in the uterine tube promote movement of the oocyte. What would likely occur if the cilia were paralyzed at the time of ovulation?arrow_forwardTest Your Understanding 13 EVOLUTION LINK Contrast the biological advantages of hermaphroditism that involves cross-fertilization with hermaphroditism that involves self-fertilization.arrow_forward
- Test Your Understanding 6 After ovulation, the secondary oocyte enters the (a) oviduct (b) corpus luteum (c) cervix (d) ovary (e) vaginaarrow_forwardWatch this video (http://openstaxcollege.org/l/ovulation) to observe ovulation and its initiation in response to the release of FSH and LH from the pituitary gland. What specialized structures help guide the oocyte from the ovary into the uterine tube?arrow_forwardChronicle the events of the female sexual cycle including hormonal control with particular emphasis on the overlap and regulation of the ovarian and menstrual cycles. What are differences if fertilization does not take place vs. when a pregnancy intervenes?arrow_forward
- Which of the following events does NOT occur in preparation for pregnancy? * After fertilization progesterone & estrogen begin to decline. Without fertilization menstruation occurs. The Secretory phase is due to the growth of endometrial glans & secretion of glycogen. Progesterone & Estrogen cause thickening of the endometrium. The preparatory phase peaks at 1 week after ovulation.arrow_forwardWhich of the following describes the role of Luteinizing hormone in the ovarian cycle? o Inhibits the hypothalamus from secreting GNRH o Directly promotes thickening of the endometrium o Simulates the ovary to increase aldosterone o Induces the corpus luteum to secrete progesterone Stimulates lactation in the mammary glandsarrow_forwardThere are 6 major events in fertilization. Discuss the process of fertilization or conception, with emphasis on the sperm-egg interaction. Proteins on the sperm plasma membrane bind to ZP3 molecules within the zona pellucida of the egg. Why is this event important? Zona binding triggers the acrosome reaction, in which the sperm plasma membrane fuses with the outer acrosomal membrane, causing exocytosis of acrosomal contents. What is in the "acrosomal content"? Acrosomal enzymes begin to dissolve a hole in the zona pellucida. This enzymatic degradation, accompanied by rapid sperm tail beating, moves the sperm through the zona. Where does the sperm intend to reach?arrow_forward
- Which of the following does NOT aid the sperm in fertilization? * Increased mitochondria Cytoplasmic bridge Acrosomes Flagellum development Hyaluronidase & proteasearrow_forwardDraw two graphs that illustrate the uterine and ovarian cycles. Explain the functions and FSH, LH, estrogen, and progesterone, giving a step-by-step explanation of maturation of a follicle, ovulation, and the corresponding stages of development of the endometrium.arrow_forwardDescribe the 28-day uterine cycle in females, citing important timeframes/hormones/events in the cycle. Your response must include the difference between fertilization occurring and fertilization not occurring throughout this cycle and how that would effect the cycle's "completion" (What I mean by this is describe the entire cycle and how it would change if a zygote is successfully formed and implanted into the uterus resulting in pregnancy)arrow_forward
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