The Menstrual Cycle

Menstrual Cycle Phases

• Ovulation occurs during the ovulatory phase of the menstrual cycle.

Menstrual Cycle Duration

• The approximate duration of the menstrual cycle is around 28 days.

Menstruation

• During menstruation, the uterus sheds its lining, resulting in bleeding.

Hormone Functions

• Progesterone is responsible for the development of the corpus luteum.

Estrogen Role

• Estrogen plays a crucial role during the preovulatory phase, stimulating the growth and maturation of ovarian follicles.

Corpus Luteum Function

• The corpus luteum produces progesterone, which prepares the uterus to implant a fertilized egg and maintains pregnancy.

Ovulation and Follicle Development

• After ovulation, the vesicular ovarian follicle ruptures, releasing the egg.

Luteal Phase

• The post-ovulatory phase is also known as the luteal phase.

Corpus Luteum Fate

• If fertilization and implantation do not occur, the corpus luteum degenerates.

Initiation of Menstrual Phase

• If fertilization and implantation do not occur, the drop in progesterone levels initiates another menstrual phase.

Hormone Maintenance

• Human chorionic gonadotropin (hCG) maintains the corpus luteum until the placenta takes over its hormone-producing function.

Corpus Luteum Role After Placenta Takes Over

• Once the placenta takes over, the corpus luteum degenerates.

Secretory Phase

• The secretory phase of the uterus is also known as the luteal phase.

Hormone Support for Pregnancy

• Progesterone supports pregnancy and breast development for lactation during the time the corpus luteum is maintained.

Endometrium During Secretory Phase

• During the secretory phase, the endometrium thickens, preparing for a fertilized egg to implant.