Reproduction online lab

Event 1: Fertilization- This is the beginning of the pregnancy. I don't know if it counts but it seem significant to me since this is where it all begins. Sperm and egg meet and form a zygote. The zygote divides over and over as it travels down the oviduct.




Event 2: Implantation- Happens during week two. The zygote implants on the uterine wall. Woman is now officially pregnant.

Event 3: Heart begins to form- Happens at around 21-23 days gestation. This is significant because at this point many women do not even know they are pregnant! Important development of body systems happens early on.

Event 4: Formation of body stalk- This occurs at about 4 weeks. The body stalk becomes the umbilical cord which will connect the developing embryo to the placenta. The umbilical cord is vital for the survival of the fetus.

Event 5: Formation of the linbs- Little buds appear around the fifth week, these buds will become arms and legs. Again important because this early dvelopment is often happening before the woman knows she is pregnant. The embryo is still only about 7 mm long.

Event 6: Bone is starting to replace catilage- At around the 11th or 12th week bone begins to 1replace cartilage. Ossification centers begin to appear in most bones. I find it fascinating that all of this is going on inside the womb.

Event 7: Circulatory system- By the 16th week the circulatory system is functioning and the heart is pumping about approximately 24 quarts of blood a day. Significant because this is such a vital system.

Event 8: First movement felt- Times vary from person to person but this usually occurs around the fifth month. At this point in development the fetus is large enough for the mother to actually feel movement. This is an important "bonding" moment for mother and child.

Event 9: Immune system develops- Around 32 week the immune system begins to develop. This system is important for fighting infections.

Event 10: Child turns head down- Sometime during the last month the child will turn so the head is positioned for birth. Of course in some cases this does not happen and a child is in the breech position. This can complicate the birth.