PHAR 303 Lecture Notes - Lecture 20: Corpus Luteum, Female Reproductive System, Anterior Pituitary
15 Feb 2018
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Around day 7 in rats, and 6 in mice, implantation occurs. After implantation, get embryogenesis: all tissues get identified. This is followed by fetal development until parturition (birth). Lactation window is variable: 3 weeks in rodents/mice/rats, in humans, it can vary, with 6 months being recommended. Toxicants can come at any point in these windows and have different actions and effects. The reproductive cycle is divided into three different segments: fertility segment 1: from gametes to the. Figure 1: the reproductive cycle zygote: gametogenesis, fertilization and up to implantation: segment 2: from implantation to birth, when all tissues develop, segment 3: from birth to adult. All gametes in females are formed before birth. In humans, about 6 million eggs are made before birth: by puberty there are only 300 000 left, and by menopause less than a 100 000. Thus all gametes a woman has are acquired during fetal life.
