reproduction. early developmental stages ●fertilization- is the union of a sperm and an egg from...
Post on 19-Jan-2018
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Embryonic Development ●The length of time from conception to birth is approximately nine months ●During the first stages of development an organism is called an embryo ●Cleavage is cell division without growth or in other words the number of cells are increased, not the volume ●Cellular stages of development : the cleavage makes a multicellular embryo and then the formation of the blastula ●Cleavage results in uniform cells which form the morula (ball of cells). A blastula is then formed after the morula continues to divide. ●Blastula- is a hollow ball of cells which have fluid filled cavity called a blastocoel ●HCG or the human chorionic gonadotropin is produced by a developing embryo during pregnancy and maintains the corpus luteum as well as the uterine lining needed to sustain a pregnancy
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