Female reproductive tract and oocyte development
ï¿½ Cambridge University Press 2013. Introduction: The human female reproductive tract has a number of critical functions. It is not only required to produce functional gametes as in the male, but also to provide an appropriate environment for fertilization of the ovulated egg to occur, to support early embryo development, to ensure the uterus is primed for implantation and to nourish and nurture the development of the growing fetus until birth. To achieve these multiple functions, multiple organs and tissues are required with complex regulatory mechanisms. It is the intention of this chapter to first describe these organs and then discuss their function as it pertains to the generation of a child. The female reproductive tract consists of the ovary where oocytes develop and from where mature eggs are ovulated. Eggs are ovulated into the fallopian tubes, also known as oviducts, and it is within these tubes that fertilization occurs. The fertilized oocyte, known as a zygote, begins a course of cell division which marks the beginning of embryonic development. The conceptus continues to develop (discussed in Chapter 12) as it passes through the oviduct and into the uterus, where the mature blastocyst hatches, implants and continues to develop into a fully formed fetus. At birth, the fetus is expelled from the uterus and passes through the cervix, down the vagina and is born (Fig. 4.1a). The first part of this chapter describes each part of the female reproductive tract while the second part returns to the topic of female gamete generation. Although the focus is primarily upon human reproduction, studies in other species will also be included where they lend insight into function. Indeed, a number of animal studies are directly relevant as such investigations routinely form the basis for human research owing to ethical reasons and the scarcity of human tissues.