1. Pregnancy
Upper Middle Level Health

2. Pregnancy We have discussed the parts of the reproductive system.
However, it’s not just enough to know the parts. It’s also important to understand how the system works, how pregnancy happens.

3. The Components of A Cell
Cell membrane - The thin membrane that surrounds every cell.
Cytoplasm - The jelly-like material inside a cell’s membrane, and all the parts floating in it except the nucleus.
Nucleus - The core of a cell, which contains the chromosomes.

4. The Components of A Cell
1. DNA - Deoxyribonucleic acid. The hereditary chemical of which genes and chromosomes are made.
1. Genes - The microscopic messenger codes inside each cell of our bodies. They carry the plans for many things about us; whether we are male or female; what color hair, skin, eyes we’ll have; how we’ll become, how our bodies will work, etc.
2. You can think of genes as the “blue print” of our bodies.
1. Chromosomes - A string of genes.

5. The Components of A Cell
An egg cell (Ovum) and a sperm cell each have 23 chromosomes.
When the two have joined together at fertilization there are a total of 46 chromosomes. We all have 46 chromosomes.

6. Process of Fertilization
1. Fertilization - When an ovum and sperm cell join.
2. Sperm are released into the vagina during ejaculation.
2. Sperm travel up through the cervix, into the uterus, and up into the fallopian tubes where the sperm cell will meet the egg cell.
2. Only one sperm cell will enter an egg cell to cause fertilization.
Fertilized Egg - What an ovum is called after the chromosomes from a sperm have mixed with the ovum’s chromosomes.

7. Implantation
1. Fertilized egg multiplies into a ball of cells as it travels through the fallopian tube into the uterus.
1. Ball of cells “nests” in uterus
2. Implantation - The ball of cells (that used to be a single fertilized egg) nesting in the wall of the uterus.

8. Implantation Fertilization + Implantation = Conception
Conception - The beginning of a pregnancy. Conception is fertilization of an ovum by a sperm, followed by implantation in the uterus.

9. Twins
Identical Twins
Twins that grew from one egg, fertilized by one sperm, that split into two balls of cells before it implanted in the uterus. They have the same genes, so they look exactly alike.

10. Twins
Fraternal Twins
Twins that grew from two eggs, each fertilized by a different sperm. They don’t look any more alike than any brothers and sisters because they have different genes.

11. Gender Determination 1. Mother = xx chromosomes
1. Father = xy chromosomes
1. One chromosome from each person joins together
2. Baby Girl = xx chromosomes
2. Baby Boy = xy chromosomes
It is the father’s chromosome which determines whether one will have a boy or a girl.

12. Pregnancy
Embryo - The developing baby from implantation to about 10 weeks. After 10 weeks it is called a “fetus”.
Amniotic Fluid - The “water” in which a developing baby floats. It acts as a cushion.
Amniotic Sac - The thin membrane that surrounds the amniotic fluid and the fetus.

13. Pregnancy
Placenta - An organ that grows inside the uterus during pregnancy to carry food and oxygen from the mother and waste from the embryo or fetus. It produces many hormones that affect both the mother and the baby. It develops from the original ball of cells that implanted in the uterus.
Umbilical Cord - The tube leading from the navel of the embryo or fetus to the placenta. It carries food and oxygen to the developing baby, and waste from the developing baby.

14. Reference Sheets Pregnancy Reference Sheets 1 - 4.
Discuss Prenatal Development
How the fetus grows in the uterus before birth

15. Reference Sheets
Reference Sheet 4
Glossary and Resources

16. Pregnancy Problems 1. Miscarriage
2. A pregnancy ending much too soon, before the embryo or fetus is able to live outside the uterus.
1. Birth Defects
2. A disability that a baby is born with (retardation, heart problems, blindness, cerebral palsy, Downs Syndrome, etc.

17. Pregnancy Problems
1. Premature Birth
2. Born “too” soon...after fewer than 38 weeks of pregnancy. Depending on how early she or he is born, a premature baby may have serious birth defects or problems and die, minor birth defects or problems and do OK with help from the hospital, or no birth defects or problems and do just fine.

18. Pregnancy Problems 1. Low Birth Weight
2. A baby that is “too” small...less than five and a half pounds at birth. A “low birth weight” baby is more likely to be sick or have birth defects; it is also likely to develop more slowly and to have more difficult in school. He/She may turn out healthy and do just fine.

19. Pregnancy Problems Miscarriages and birth defects may be caused by:
a chromosomal abnormality in the ovum or sperm (more than 23 or less than 23 chromosomes)
Mother’s/Father’s consumption of drugs and/or alcohol
Mother’s illness, including STD’s
Radiation and environmental pollution

20. Pregnancy Problems Miscarriages and birth defects may be caused by:
Mother’s age (the healthiest, safest time is in her 20’s and early 30‘s
Father’s age
Birth trauma (Forceps delivery, Vacuum Delivery)
Baby’s illness
Unknown factors

21. Pregnancy Problems
Some possible reasons for the especially high rate of birth defects, miscarriages, premature birth, and low birth weight in babies born to TEENS are:
No/Poor prenatal care
Late Prenatal care
Poor Nutrition
Consumption of alcohol, cigarettes and other drugs
High rates of STD’s among teens

22. Homework
Birth Information Sheet
Due: Next class period!