Menstrual Cycle
- Begins in girls at 12-13 years of age
- Lasts about 28 days (may vary:20-45)
- Two separate cycles controlled by ovarian hormones (mainly estrogen and progesterone) and pituitary hormones (mainly FSH and LH)
1)Ovarian Cycle- Occurs in the ovaries
2)Uterine Cycle- Occurs in the uterus
The following diagram shows the components that are present in the menstrual cycle.
Ovarian Cycle
This video provides a graphic illustration of the process of ovulation.
Source: http://www.youtube.com/watch?v=I0RsB1dj55o
Source: http://www.youtube.com/watch?v=I0RsB1dj55o
1) Each follicle in the ovary contains an immature single ovum.
2) In one ovarian cycle, one follicle in the ovary matures and releases a single ovum.
3) Once ovum is released, the existing follicle develops into a yellowish gland structure known as the corpus luteum, which then degenerates if fertilization does not occur. This repeats every month.
2) In one ovarian cycle, one follicle in the ovary matures and releases a single ovum.
3) Once ovum is released, the existing follicle develops into a yellowish gland structure known as the corpus luteum, which then degenerates if fertilization does not occur. This repeats every month.
Uterine Cycle
This video illustrates a graphic illustration of how reproductive hormones affect the female system. Source: http://www.youtube.com/watch?v=NLuGQM3mQlU
Essentially, after the end of menstruation, the endometrium begins to grow and thicken in cells, blood vessels, and glands.
Menstruation Summary:
This chart illustrates the events that occur in both the ovarian/uterine cycles, as well as the effects of the pituitary and sex hormones on the female reproductive system.