Answer:
The menstrual cycle is a complex process that is regulated by a number of different hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone. The cycle is typically divided into four phases: the menstrual phase, the follicular phase, the ovulatory phase, and the luteal phase.
During the menstrual phase, which lasts for about 3-7 days, the uterus sheds its lining in response to a drop in estrogen and progesterone levels. This is triggered by the breakdown of the corpus luteum, which is a structure that forms in the ovary after ovulation and produces progesterone.
Following the menstrual phase, the follicular phase begins. This phase lasts for about 7-14 days and is characterized by the development of a new follicle in the ovary. FSH stimulates the growth of the follicle, which in turn produces estrogen. As estrogen levels rise, they cause the lining of the uterus to thicken in preparation for a potential pregnancy.
The ovulatory phase occurs around day 14 of the menstrual cycle, when the mature follicle ruptures and releases an egg. This process is triggered by a surge in LH, which is also responsible for the formation of the corpus luteum. The egg then travels down the fallopian tube towards the uterus.
During the luteal phase, which lasts for about 14 days, the corpus luteum continues to produce progesterone. This hormone helps to maintain the thickened uterine lining and prepares the body for pregnancy. If the egg is fertilized, it will implant in the uterus and the corpus luteum will continue to produce progesterone. If the egg is not fertilized, the corpus luteum will break down and hormone levels will drop, triggering the start of a new menstrual cycle.
Overall, the menstrual cycle is a complex process that is regulated by a number of different hormones, including FSH, LH, estrogen, and progesterone. These hormones work together to prepare the body for pregnancy and ensure that the menstrual cycle occurs on a regular basis.