Period of The Zygote
Renee Harris
Period of the Zygote
January 30, 2013
Child Development 101 Section KM
Professor Brown
The period of the zygote begins at fertilization. After a female egg is fertilized, the resulting one celled organism becomes known as a zygote. Once the egg is fertilized, the zygote begins a two-week period of rapid cell division and will eventually become an embryo. The zygote divides through a process known as mitosis, in which each cell doubles by dividing into two cells. This two-week stage is known as the germinal period of development and covers the time of conception to implantation of the embryo in the uterus. In most cases, each male and female sex cell contains 23 chromosomes. When these two haploid cells join, they form a single diploid cell that contains a total of 46 chromosomes. The zygote begins a journey down the fallopian tube to the uterus where it must implant in the lining in order to obtain the nourishment it needs to grow and survive. The period of the zygote lasts for about four days. Around the fifth day, 60 to 70 cells exist that form a hollow, fluid filled ball called a blastocyst. The embryonic disk will become the new organism; the outer ring will provide protective covering. Implantation occurs sometime between the seventh and ninth day which the blastocyst burrows deep into the lining of the uterus. The amnion is a membrane that encloses the developing organism in amniotic fluid. The fluid functions as a cushion and temperature regulator. The yolk sac produces blood cells until the liver, spleen, and bone marrow mature enough to take over this function. The chorion, a protective membrane develops around the amnion by the end of the second week. The placenta is a special organ that permits food and oxygen to reach the zygote and waste products to be carried away. The umbilical cord connects the placenta to the developing organism. The period of the embryo lasts from implantation through the
Period of the Zygote
January 30, 2013
Child Development 101 Section KM
Professor Brown
The period of the zygote begins at fertilization. After a female egg is fertilized, the resulting one celled organism becomes known as a zygote. Once the egg is fertilized, the zygote begins a two-week period of rapid cell division and will eventually become an embryo. The zygote divides through a process known as mitosis, in which each cell doubles by dividing into two cells. This two-week stage is known as the germinal period of development and covers the time of conception to implantation of the embryo in the uterus. In most cases, each male and female sex cell contains 23 chromosomes. When these two haploid cells join, they form a single diploid cell that contains a total of 46 chromosomes. The zygote begins a journey down the fallopian tube to the uterus where it must implant in the lining in order to obtain the nourishment it needs to grow and survive. The period of the zygote lasts for about four days. Around the fifth day, 60 to 70 cells exist that form a hollow, fluid filled ball called a blastocyst. The embryonic disk will become the new organism; the outer ring will provide protective covering. Implantation occurs sometime between the seventh and ninth day which the blastocyst burrows deep into the lining of the uterus. The amnion is a membrane that encloses the developing organism in amniotic fluid. The fluid functions as a cushion and temperature regulator. The yolk sac produces blood cells until the liver, spleen, and bone marrow mature enough to take over this function. The chorion, a protective membrane develops around the amnion by the end of the second week. The placenta is a special organ that permits food and oxygen to reach the zygote and waste products to be carried away. The umbilical cord connects the placenta to the developing organism. The period of the embryo lasts from implantation through the