Chapter 8.4+8.5 Flashcards
ovum
the female sex cell, or egg.
fertilization
the union of the ovum and sperm.
zygote
cell resulting from the uniting of the ovum and sperm.
monozygotic twins
identical twins formed when one zygote splits into two separate masses of cells, each of which develops into a separate embryo.
dizygotic twins
often called fraternal twins, occurring when two individual eggs get fertilized by separate sperm, resulting in two zygotes in the uterus at the same time.
bioethics
the study of ethical and moral issues brought about by new advances in biology and medicine.
Which three stages of development is their?
Germinal period, embryonic period, fetal period
germinal period
first 2 weeks after fertilization,
during which the zygote moves down to the uterus and begins to implant in the lining.
embryo
name for the developing organism from 2 to 8 weeks after fertilization.
embryonic period
the period from 2 to 8 weeks after fertilization, during which the major organs and structures of the organism develop.
critical periods
times during which certain environ- mental influences can have an impact on the development of the infant.
teratogen
any factor that can cause a birth defect.
fetal alcohol spectrum disorder (FASD)
the physical and mental defects caused by consumption of alcohol during pregnancy.
fetal period
the time from about 8 weeks after conception until the birth of the baby.
fetus
name for the developing organism from 8 weeks after fertilization to the birth of the baby.