![]() ![]() Furthermore, they found inĪddition to their critical role in oocyte pickup, oviductal cilia have two additional fertility-promoting functions in female mice: controlling sperm migration to the site of fertilization and transporting the embryo from the site of fertilization in the oviductal ampulla to the uterus for implantation…. observed that, after they had been released from the ovary, oocytes did not enter the oviducts of the knockout mice but rather accumulated in the bursal cavity outside of the oviduct. Their infertility resulted, instead, from a failure of oocyte pickup” Yuan et al. The results of this study showed the cilia were essential because all “Knockout females were infertile, even though they produced normal amounts of oocytes and reproductive hormones. Called knockout mice because the miRNA that produce the cilia were removed, knocking out the motile cilia. They produced a modified strain of female mice whose oviducts were largely devoid of motile cilia. ![]() The research that determined these factors was critical was done by Yuan et al. The tiny motile cilia that coats the lining of the infundibulum is now recognized as far more complex and important than previous believed. It is this portion of the oviduct that is responsible for capturing the oocyte when it is expelled from the ovary. The space between the oocyte and the oviduct at the extremity of the oviduct is a funnel-shaped cavity called the infundibulum. demonstrate, “the carpet of tiny motile cilia that coats the lining of the infundibulum is crucial to successful oocyte pickup and transport into the oviduct.” It was once thought, in contrast to this new finding, that “Although the cilia lining the tubal mucosa may also play a role in egg transport, their action is not obligatory because women with immotile cilia syndrome are often fertile.” We are alive because of a “magic carpet of fully motile cilia” that move the eggs into the oviduct toward the uterus. Note the finger-like projections at the beginning of the oviduct called fimbria where the egg travels toward the uterus. The second is transport of the oocyte through the oviductal ampulla, as shown in the illustration below.įigure 1. The first is the oocyte is picked up by the oviduct fingers called fimbria. Two steps are involved in oocyte transport from the ovary to the oviduct. Fertilization in eutherian mammals (all placentals excluding marsupials and monotremes) cannot occur unless the oocytes (the mother’s eggs) released by the ovary are able to enter the oviduct (or uterine tube, formally called the fallopian tube). The first step in fertilization is when an egg is released from the ovary, a process called ovulation. The design of the tiny motile cilia explained in this review is just one of the latest of many examples. While denying the concept of irreducible complexity (IC), scientists continue to provide a steady flow of well documented new examples of IC. Looking for evidence of intelligent design requires looking at, not only the big picture, but also the smallest details, such as the tiny motile cilia in the female reproductive system. Another Example of Irreducible Complexity
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