2.2 Flashcards
Fertilization
Joining of sperm and egg to make the zygote
Where is the ovum fertilized?
In the fallopian tube
What are the stages of prenatal development
Germinal
Embryonic
Fetal
When is the germinal stage
Fertilization-2 weeks
When is the embryonic stage
2-8 weeks
When is the fetal stage
8 weeks-birth
What happens in germinal stage
Zygote undergoes cell division and becomes blastocyst, moves towards uterus
What happens in embryonic stage
Organism now called embryo
embryo firmly attached to uterine wall
Child develops three layers
nervous system begins to function at week 5
What are the three layers of the embryo
Ectoderm
Mesoderm
Endoderm
Ectoderm
Outer layer
Forms skin, teeth, sense organs, brain, spinal cord
Mesoderm
Middle layer
Forms muscle, bones, blood, circulatory system
Endoderm
Inner layer
Forms digestive system, liver, pancreas, respiratory system
What portion of the organism undergoes most rapid growth during embryonic period?
Head and brain
What happens in fetal stage
Organism now called a fetus Increases in size Organs differentiate and start to work They can start learning Sex differentiation
Infertility
Inability to conceive after 12-18 mo of trying
What are some treatments for infertility
Artificial insemination
In vitro fertilization
Artificial insemination
Sperm placed directly in woman’s reproductive tract by physician
In vitro fertilization (IVF)
Egg is fertilized by sperm in a lab
Ethical issues with surrogate mothers
Some surrogates refuse to give up child after birth
Surrogate mother may try to seek a role in childs life after birth
Difference between miscarriage and abortion
Miscarriage is involuntary
Abortion is voluntary
Teratogen
Environmental factor that produces a birth defect
T/F placenta can block teratogens from the fetus
False
T/F teratogens are always severely harmful
False, timing is important. Some teratogens are more harmful early on, but don’t make a difference later in development
T/F even a small quantity of a teratogen is guaranteed to harm
False
Quantity matters
