Q. Including major events and hormonal changes how can the menstrual cycle be described?
One can imagine a cycle like an analog clock at which at 0 o'clock is the beginning and the end of the menstrual cycle and that 6 o'clock corresponds to the 14h day of the cycle and at 0 o'clock the menses and so the menstrual cycle begins and FSH blood level begins to rise.
Around 2 o'clock the maturing follicles under FSH action are already secreting estrogen and the endometrium is thickening and around 3 o'clock estrogen is intensely stimulating the rise of LH blood level. At 6 o'clock (the 14th day) LH is at its maximum concentration and FSH also at high levels to promote ovulation, LH then stimulates the formation of the corpus luteum and around 7 o'clock the corpus luteum is already secreting a great amount of progesterone and estrogen and the endometrium thickens even more, concomitant lowering of FSH and LH occurs with the increasing of the ovarian hormones.
Around 11 o'clock the reduced FSH and LH levels make the corpus luteum turn into the corpus albicans the production of progesterone and estrogen ceases and the endometrium regresses and At 0 o'clock again (28th day) the endometrium desquamates and a new menstrual cycle begins.