This animated video tells us how the female endometrial lining of the uterus is regulated by means of different hormones. Endometrial preparation is necessary for a female's reproductive success as it allows the embryo to be implanted and placenta to be formed. Timeline: 0:00 Introduction 0:46 stimulation by GnRH (release of LH & FSH) 2:05 occurance of ovulation 2:50 menstural cycle