Menstrual cycle is the reproductive cycle in all primates and begins at puberty(menarche). In human females, mensutration occurs once in 28 to 29 days. The cycle of events starting from one menstruation till the next one is called the menstrual cycle.
During the middle of the menstrual cycle, one ovum is released (ovulation). The cycle starts with the menstrual flwo (3 to 5 days), caused due to breakdown of hte endometrium of the uterus. Blood vessels in liqud state are discharged, but that occurs only when the ovum is not fertilised.
It is followed the follicular phase where the primary follicle mature into Graffian follicles. This causes follicular growth and the growing follicles produce oestrogen. The LH and FSH are at their peak in the middle of the cycle (14th day) and cause the rupture of the Graffian follicles to release ovum. This phase is called the ovulatory phase.
The remains of the Graffian get converted into the corpus luteum, which secretes progesterone for the maintenance of the endometrium.
In the absence of fertilisation, the corpus luteum degenerates, thereby causing the disintegration of the endometrium and the start of new cycle.
