Practice:Myscrachpad/ My Practice Area

zygote, to becoming a [[Media:[[Media:Example.ogg]]

= =Social Organization= = Example.ogg]]fetus, the three trimesters, and the progressive development of the fetus through the weeks of pregnancy. It will cover the topic of birth and different birthing methods.

[edit] Fertilization Fertilization is the joining of a sperm and an egg. A sperm is a male gamete that is released into the vagina of a female during intercourse. In order for fertilization to occur there must be a mature ovum present. Every month the ovaries release an egg. The sperm swim through the cervix and into the uterus which lead to the follapian tubes, this is where fertilization is most likley to take place. The sperm come in contact with the egg and the acrosome on the head of the sprem has a special enzyme to break down the corna radiata and the zona pellucida which are the protective membranes of the ovum (egg). Once the sperm reaches the inside of the egg it sheds its tail and the two nuclei fuse and now the 23 chromosomes from the egg and the 23 chromosomes of the sperm join and they become a zygote.Chromosomes contain all the information needed to determine the genetic structure of the new baby. Normally all human beings have two chromosomes. A combination of either an XY(male) or XX (female) all ovum are X sperm are both X's and Y's, so they determine the sex of the baby.

[edit] Preembroyonic Period After fertilization,the zygote begins a process of dividing called cleavage. It divides until it reaches 16 cells. It is now referred to as a morula. As the morula floats freely within the uterus, it starts to bring nutrients into the cells. The morula fills with fluid and the cells inside start to form two separate groups. At this stage it is now a blastocyte. The inner layer of cells is called the embryoblast, and the outer layer is called a trophoblast.The trophoblast will develop into part of the placenta, and the embryoblast will form into a human being.

[edit] Implantation The Zygote divides into two cells, then four, then eight, and so on. This process of dividing is called cleavage.It then becomes a morula at a