Question

Which of the following is NOT a phase of the menstrual Cycle? Multiple Choice

 proliferative

 secretory

 ovulation

 menstruation

Answer 1

In women, there is an ovarian cycle and a menstrual cycle. Ovarian cycle has three stages- follicular phase, ovulation and luteal phase. Menstruation initiates the follicular phase, where there is development of the ovarian follicle and production of estrogen. Follicular phase is followed by ovulation, where the egg is released and theca cells of the ruptured follicle become corpus luteum and start secreting progesterone. The luteal phase is where the FSH levels rise and there is progesterone production by the corpus luteum.

The menstrual cycle or uterine, associated with changes in uterine endometrium, has three phases. They are menstruation phase, proliferative phase and secretory phase. Ovulation is not a phase in menstrual cycle as it is only occurring in the ovary. Menstrual cycle is based on effects of ovarian hormones on uterine endometrium. In proliferative phase, ovarian estrogen will stimulate the endometrial cells to proliferate. In secretory phase, the ovarian progesterone induces differentiation of the endometrial cells for preparation of the embryo implantation. The endometrium will break down in menstruation phase, due to loss of ovarian hormone in cirulation, exposing the blood vessel. Hence, there is visible bleeding.

Ovulation is a phase of ovarian cycle and not of menstrual cycle. However it separates the proliferative phase from the secretory phase. LH surge that induces ovulation, does not really affect the endometrium.

Right choice: Ovulation.