Describe, how the changing levels of FSH, LH and progesterone during menstrual cycle induce changes in the ovary and the uterus in human female.

Explanation

Menstrual cycle represents the cyclic changes in the female reproductive tract. This cycle consists of three phases, i.e. the menstrual, proliferative and secretory or Iuteal phase.
The menstrual phase (menstruation) is followed by follicular or proliferative phase, it is under the influence of Follicle Stimulating Hormone (FSH) released from the anterior pituitary.
The primary follicle matures into Graafian follicle, these follicular cells secrete oestrogens, which control the growth and maintenance of the secondary sex organs like uterus, Fallopian tube, etc.
The endometrium of uterus regenerates by proliferation of its cells.
The FSH and luteinising hormone reach their peak level around the 14th day of menstrual cycle.
The peak level of LH (LH surge) causes the rupture of Graafian follicle and releases of ovum, this process is called ovulation.
It is followed by luteal phase, where LH influences the ruptured Graafian follicle to transform into corpus luteum and secrete progesterone.
Corpus luteum secretes large quantity of progesterone in the luteal phase, which is necessary for the growth and maintenance of endometrium of uterus for implantation.
If fertilisation does not occur, corpus luteum degenerates and progesterone is not secreted.
The endometrium degenerates and menstruation occurs.