The menstrual cycle includes all the cyclic changes that occur in the endometrium of the uterus every month under the influence of the ovarian hormones (estrogen and  progesterone). They stimulate the development of the endometrium and prepare it  for implantation of a zygote. If pregnancy does not occur, the drop in FSH and LH [...]

The  length of the ovarian cycle is typically 28 days, but it may vary from 24-32 days . It starts at puberty (11-13 years) , usually stops during pregnancy and sometimes during lactation and ends at menopause (45-50) , when reproductive capability ends. After puberty ,  the ovary cycles between a follicular phase (maturing follicles) and [...]

              The formation of gametes (primary sex cells) is the basic process in embryology , it represents the first step in creation of a new human being and it is called gametogenesis . The gametes are produced from primordial germ cells , formed in the ectoderm during 2nd week  and move to the wall of [...]

Fertilization is the first stage of human development according to the basics of embryology . This process begins when a sperm unites with the mature ovum and it ends with the creation of the zygote . It normally occurs in the lateral third ( ampullary) part of the uterine tube, the widest part that lies close to the ovary, and usually fertilization process takes about 24 hours.

Aristotle , in the 4th century B.C., promoted the idea that the embryo develops from a formless mass that resulted from the union of semen with menstrual blood. Aristotle believed that the male was the major factor in reproduction, although he did grant that the female supplied the matter for shaping. Galen , 2nd century A.D., wrote a book entitled “ On the formation of the foetus”, also held the two-seed doctrine, claiming both the male and female seeds had coagulative power and receptive capacity for coagulation but that one was stronger in the male and the other in the female.From the time of Galen , until the 16th century, the prevailed wrong misconception that the embryo will grow in the uterus containing clotted menstrual blood as a seed till complete growth, with no record of major advances in the field of embryology.