The Life Cycle: Journey from Single Cell to Trillion-Cell Marvel

1. Your Life Began as a Single cell, smaller than this period at the end of this sentence . Now your body is made up of trillion of cells, forming the organs, and tissues in your body!! The Life Cycle • This microscopic cell formed by the union of an egg cell (Ovum), from the Female and a Sperm cell from the Male. This is called FERTILIZATION. Also known as CONCEPTION. • The resulting cell is now called a Zygote.

2. How it all starts……..    Each woman is born with two ovaries that are positioned in her pelvis. These oval-shaped organs produce one egg per month in response to the woman’s monthly cycle of hormones. Generally, one ovary produces one egg one month and the other ovary produces an egg the next month.

4. Implantationis when the Zygote attaches to the Uterine Wall. • The Cluster of cells that was once called a Zygote is now called an Embryo during the third and eight weeks of pregnancy. • From the eighth week of pregnancy until term , the developing cluster of cells is called the Fetus.

5. Zygote

6. Embryo 9 weeks

7. Fetus

9. Embryonic GrowthAs the embryo continues to divide , it forms 3 tissue layers that later become Various body systems. • 1st layer becomes the Respiratory and Digestive system. • 2nd Layer develops into Muscle, Bones, blood vessels, and skin. • 3rd layer forms the nervous system, sense organs, and mouth.

10. Amniotic Sac is a thin, fluid- filled membrane that surrounds and protects the developing embryo.

11. Stages of Birth 1st- Dilation 2nd- “Crowning” passing through the birth canal 3rd- Afterbirth

12. Placenta is a thick-rich tissue that lines the walls of the Uterus during pregnancy and nourishes the embryo.

13. Umbilical Cord A rope like structure that connects the embryo and the mother’s Placenta.

14. 9 months/ 3 month periods called TRIMESTERS Pg. 488 Figure 19.2 Review Trimesters Fetal Development

16. How do Twins Form??

17. Identical twins result when a single egg has been fertilized by one sperm, it divides and forms two embryos. Being that they originated form the same zygote, identical twins have the same genetic make-up. Fraternal twins form when the ovaries release two egg’s. Therefore two sperm fertilize each egg and two embryos develop. The genetic make-up is different

19. The Health of the Fetus Tobacco, alcohol, and other drugs used by the mother can enter the body of the developing fetus and have harmful effects. Tobacco and Pregnancy • It is estimated that smoking accounts for up to ; • 30 % of low birth weight babies • 14% of premature births • 10% of all infant deaths. • Pregnant females repeatedly exposed to secondhand smoke also have increased of have low birth weight babies!

20. Alcohol & Pregnancy Any Alcohol consumed during pregnancy quickly passes through the umbilical cord to the Fetus. Fetal Alcohol Syndrome(FAS) • A group pf alcohol-related birth defects that includes both physical & mental problems. Life Consequences: • Mental retardation, learning disabilities • Serious behavior problems, slowed growth • Physical deformities; including a small skull, abnormal facial features, heart defects.

21. Common Physical effects of FAS

22. Medicines,other drugs, and Pregnancy • Serious consequences using drugs, even over-the counter medicine are: -weakened mother’s immune system, resulting in improper care of the baby. -Hinder fetal development -birth defects,premature labor, miscarriage -The baby can be born addicted to the drugs the mother uses during pregnancy, causing the baby to go through withdrawl after birth.

23. Environmental HazardsHarm to the Fetus can result when the mother is exposed to some common substances in the environment • Lead-exposure has been linked to miscarriages,low birth weight,mental disabilities & behavior problems in children. • Smog- air pollution has been linked to birth defects, low birth weight,premature birth, stillbirths, & infant death. Greatest risk is during the second month when most organs & facial features develop. • Radiation- Ionizing Radiaiton-type found in X-rays, can affect fetal growth & cause mental retardation. • Cat Litter- Contains parasites that cause a disease that can result in miscarriage,premature labor,and health problems in newborns.

24. Complications during pregnancy • Miscarriage = spontaneous expulsion of a fetus that occurs before the 20th week of a pregnancy. • A dead fetus expelled from the body after the twentieth week is called a Stillbirth. 2. Ectopic pregnancy = pregnancies result when the zygote implants in the fallopian tube, the abdomen, the ovary,or the cervix. This can occur when the fertilized egg can’t pass to the uterus, sometimes b/c of inflammation or scar tissue that has developed as a result of a Sexual transmitted disease.

25. 3. Preeclampsia = also called, toxmia, can prevent the placenta from getting enough blood, This may result in low birth weight and problems for the mother; such as high blood pressure, & swelling. 4. Gestational Diabetes = Gestational diabetes affects about 4% of all pregnant women . Gestational diabetes starts when your body is not able to make and use all the insulin it needs for pregnancy. Without enough insulin, glucose cannot leave the blood and be changed to energy. Glucose builds up in the blood to high levels. This is called hyperglycemia.