Question

Peaks of LH and FSH production occur during

(A) the menstrual flow phase of the uterine cycle.

(B) the beginning of the follicular phase of the ovarian cycle.

(C) the period just before ovulation.

(D) the secretory phase of the uterine cycle.

Short answer

(A)The option “the menstrual flow phase of the uterine cycle” isincorrect.

(B)The option “the beginning of the follicular phase of the ovarian cycle” isincorrect.

(C)The option “the period just before ovulation” iscorrect.

(D)The option “the secretory phase of the uterine cycle” is incorrect.

Step-by-step solution

Menstruation in females

Menstruation in females is a process when the uterine lining sheds if there is no fertilization. This process occurs in a 28-day cycle. Blood shedding is called a period or menstruation.

Menstruation occurs in four phases, menstruation (day 1 to 5), follicular phase (day 1 to 13), ovulation (day 14), and luteal phase (day 15 to 28). The hormones like the follicle stimulating hormone (FSH) and luteinizing hormone (LH) play an essential role in menstruation.

Explanation of option ‘(A)’

During the menstrual flow phase, the corpus luteum degenerates, so the LH level falls, and the FSH levels rise. The menstrual flow phase is when the corpus luteum and the uterine lining degenerate, so the blood sheds.

Thus, no peak can be seen in the FSH and LH during the menstrual flow phase.

Therefore, the given option is incorrect.

Explanation of option ‘(B)’

At the beginning of the follicular phase, the FSH levels are high as they develop the follicles and then slowly decrease as the follicular phase ends. The LH levels are the same as the FSH levels, but they do not decrease; instead, they keep rising slowly.

Thus, no peak of FSH and LH can be observed during the follicular phase of the ovarian cycle.

Therefore, the given option is incorrect.

Explanation of option ‘(C)’

The period just before ovulation causes the release of ova from the fallopian tube; thus, FSH levels rise instantly, and a peak can be seen. The LH levels rise and give a peak much higher than the FSH. The role of LH is to maintain the menstrual cycle during ovulation.

Thus, there is an instant rise in the FSH and LH levels, forming a peak during the initiation of ovulation.

Therefore, the given option is correct.

Explanation of option ‘(D)’

In the secretory phase or the luteal phase, the level of FSH and LH are decreased by the rising levels of estrogen and progesterone. The corpus luteum produces estrogen and progesterone for the eggs to attract the sperm; thus, FSH and LH levels are low.

Thus, the FSH and LH levels do not show a peak during the secretory phase of the uterine cycle.

Therefore, the given option is incorrect.