Name ______
Notes: The Miracle of Life
From Conception to Birth
- Sex Cells and Chromosomes
- SexCells (also called gametes)
- Female sex cell – egg cell (ovum)
- Male sex cell – sperm cell
- Sex Chromosomes
- 23 chromosomes in each sex cell
- 23rdchromosome is the “sex chromosome”
- Egg cell ALWAYS carries the “X” sex chromosome
- Sperm cellcan carry either the “X” sex chromosome or the “Y” sex chromosome
- Father determines gender of the child, because they carry both the X and Y chromosomes, while mothers only carry the X
- Genetic code for a male baby is XY and female baby is XX
- Genes
- Found on chromosomes
- Pass genetic traitsto offspring
- Inherited Traits
- Dominant – expressed if one parent has the trait
- Recessive – expressed only if both parents have the trait
B. Pregnancy
- Pregnancy
- Definition: The period of time between conception and birth.
- Measured in 3 month periods called trimesters and starts from the first day of the last menstrual period
- Normally lasts about 9 months or 40 weeks from conception to birth
- Conception
- The process of becoming pregnant including fertilization
- Starts with two tiny cells that join together to grow into a baby
- Fertilization
- The strongest, fastest and healthiest sperm have the best chance of fertilizing the egg cell
- How does a woman know she is pregnant?
- Missed or late ______
- ______tenderness or fullness
- Nausea and sometimes ______
- Changes in ______
- Frequent ______
- Tiredness
- Pregnancy Tests
- Urine test – HCG
- Pelvic exam—uterus size
C. Stages of Development
- Zygote
- Single cell formed from union of sperm and egg
- Contains genetic material from both parents
- From Zygote to Embryo
- Zygote divides into multi-celled mass called embryo, which will implant in the uterine lining
- Embryo searches for a place to implant in the uterine lining or wall
- It actually burrows beneath the surface
- From Embryo to Fetus
- After about two months, the embryo takes on a human appearance and is now called a fetus.
- Formation o Twins
- Identical - 1 egg (ovum) is fertilized by 1 sperm which then divides and separates and grows as two separate embryos
- Fraternal - 2 eggs are released from the ovary and are fertilized by 2 different sperm
D. Structures inside the Womb
- Placenta
- Grows from the outer edges of the embryo
- Connects embryo to uterine wall
- Filters nutrients and waste between mother and baby
2. Umbilical Cord
- Grows between placenta and baby
- Provides baby with oxygen and nutrients
- If mother ingests any toxic substances, such as drugs, alcohol or nicotine, the baby receives these as well
3. How can smoking during pregnancy affect the baby?
In the womb:
a.Low birth ______
b.______baby
c.Increased risk of birth ______
d.______birth
After birth:
a.______and breathing problems
b.Increase risk of ______
c.Affect on physical and intellectual ______
d.______problems
4. Did You Know…?
Pregnant women who use drugs such as heroin, cocaine, marijuana, PCP, methadone, and/or amphetamines may give birth to drug-addicted babies.
- How does alcohol use affect the baby?
- Increased risk of ______
- ______defects
- Fetal Alcohol Syndrome (______): facial abnormalities, malformations of the heart, growth retardation, and mental disorders
- Amniotic Sac
- Thin, but strong, membrane filled with fluid that cushions and protects the fetus and regulates its temperature
E. Labor and Birth
- Signs of Labor
- Water breaks: amniotic sac bursts, the fluid is released through the vaginal canal
- Contractions: uterine muscles give cramping sensation as cervix starts to dilate
- Either one can happen first. Everyone is different.
- Birth Positions
- Normal birth position – head downward in pelvis
- Breeched birth position – head anywhere else but downward
- Childbirth
- Natural birth - baby is pushed through the birth canal(vagina)
- Caesarian section is the operation performed by the doctor that removes the baby directly from the uterus by making an incision in the lower abdomen.
- Cutting and tying of umbilicalcord forms the navel
- First Breath
- The hole in the heart will close, changing the heart from a one-pump heart to a two-pump heart.
- The linking passage outside the heart will close off and force oxygenated blood to the lungs.
- Afterbirth
- Umbilical cord ceases working and is cut and clamped
- Placenta detaches from the side of the uterus and is pushed out
______
Knowledge Check:
Describe 3 signs/symptoms that a woman may be pregnant.
- ______
- ______
- ______
Describe 2 ways a woman can confirm her pregnancy.
- ______
- ______