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LSM 8.5-1 Student Worksheet

Lab Exercise 8.5.1: Hormone Levels During the Menstrual Cycle How do hormone levels regulate the female menstrual cycle? Use the following experimental data to analyze hormone levels during the menstrual cycle.

1. Gonadotropic hormones regulate ovarian hormones. Study the feedback loop shown in Figure 4.

Figure 4 Feedback loop showing the regulation of ovarian hormones by gonadotropic hormones.

(a) Identify as W, X, Y, or Z the two gonadotropic hormones represented in the diagram.

(b) Identify the ovarian hormones shown in the diagram.

(c) Which two hormones exert negative feedback effects?

2. Body temperatures of two women were monitored during their menstrual cycles. One woman ovulated; the other did not. The results are shown in Table 4 on the following page. (d) Graph the data provided on a separate piece of paper. Plot changes in temperature along the yaxis (vertical axis) and the days of the menstrual cycle along the x-axis (horizontal axis).

Table 4 Temperature (°C) Days 5 10 12 14 16 18 20 22 24 28 Ovulation occurs 36.4 36.2 36.0 38.4 37.1 36.6 36.8 37.0 37.1 36.6 No ovulation 36.3 35.7 35.8 36.2 36.1 36.0 36.3 36.3 36.4 36.5

(e) Assuming this menstrual cycle represents the average 28-day cycle, label the ovulation day on the graph. (f) Describe changes in temperature before and during ovulation.

(g) Compare body temperatures with and without a functioning corpus luteum.

3. Figure 5 shows changes in the thickness of the endometrium throughout the female menstrual cycle.

Figure 5

(h) Identify the events that occur at times X and Z.

(i) Identify by letter the time when follicle cells produce estrogen.

(j) Identify by letter the time when the corpus luteum produces estrogen and progesterone.

4. Levels of gonadotropic hormones monitored throughout the female reproductive cycle are shown in Figure 6. Levels are recorded in relative units.



(k) How does LH...
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