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The Female Reproductive System and Ovarian Cycle

Major Structures and Their Functions

  1. Fallopian Tubes

    • Transports eggs from the ovary to the uterus.

    • Site of fertilization – where sperm and egg usually meet!

  2. Fimbriae

    • Finger-like projections that sweep the egg into the fallopian tube after ovulation.

  3. Ovaries

    • Site of egg development and hormone production (estrogen & progesterone).

  4. Uterus

    • Where a fertilized egg implants and grows.

    • Inner lining (endometrium) sheds during menstruation if no pregnancy occurs.

    • Myometrium: muscular wall that contracts during birth.

  5. Cervix

    • Narrow "gateway" between uterus and vagina.

    • Acts as a barrier and also helps guide sperm during ovulation.

  6. Vaginal Canal

    • Path for sperm entry, menstruation exit, and childbirth.

The Ovarian Cycle

The ovarian cycle typically lasts around 28 days and includes 3 main phases:

1. Follicular Phase (Day 1–14)

  • Begins with menstruation (shedding of uterine lining).

  • FSH (Follicle Stimulating Hormone) causes several follicles in the ovary to develop, but only one becomes dominant.

  • Follicle produces estrogen, which helps rebuild the uterine lining.

2. Ovulation (Day 14)

  • Spike in LH (Luteinizing Hormone) and FSH triggers the release of the mature egg from the ovary.

  • The egg heads to the fallopian tube, waiting to meet sperm.

  • This is the phase when pregnancy can occur.

3. Luteal Phase (Day 15–28)

  • The ruptured follicle becomes the corpus luteum, which secretes progesterone to maintain the uterine lining.

  • If no fertilization happens, corpus luteum breaks down → hormone levels drop → menstruation begins again.

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