Prenatal Development Flashcards
conception
single sperm cell unites with ovum (egg) in female’s Fallopian tube in process called fertilization
germinal period
prenatal development in first 2 weeks after conception, creation of fertilized egg (zygote), cell division, attachment of zygote to uterine wall
blastocyst
inner mass of cells that eventually develop into an embryo (during germinal period)
trophoblast
outer layer of cells that later provides nutrition and support for the embryo (during germinal period)
implantation
attachment of zygote to uterine wall, takes place about 11-15 days after conception
embryonic period
period of prenatal development from 2-8 weeks after conception
endoderm
embryo’s inner layer of cells that will become digestive and respiratory systems (develops during embryonic period)
mesoderm
embryo’s middle layer of cells that will become circulatory system, bones, muscles, excretory system, and reproductive system (develops during embryonic period)
ectoderm
embryo’s outer layer of cells that will become nervous system and brian, sensory receptors (eyes, nose, ears), and skin parts (such as hair and nails), (develops during embryonic period)
amnion
bag or envelope of the embryo that contains a clear fluid in which the developing embryo floats
umbilical cord
contains two arteries and once vein and connects baby to placenta
placenta
disk-shaped group of tissues in which small blood vessels from the mother and offspring intertwine but do not join
organogenesis
process of organ formation during the first 2 months of prenatal development, during which the organs are especially vulnerable to environmental changes
fetal period
lasts 7 months, prenatal period between 2 months and birth in typical pregnancies
viable
a fetus is considered viable at 7 months
neuron
nerve cell which handles info processing at the cellular level in the brain, 100 billion by the time the baby is born
neural tube
forms from ectoderm, closes at top & bottom, birth defects-anencephaly & spina bifida
neurogenesis
generation of new neurons
neuronal migration
cells move outward from point of origin to appropriate locations and create different levels, structures, & regions of the brain
teratogen
any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes
dose
greater dose of teratogen, greater effect
genetic susceptibility
type/severity of abnormalities caused by a teratogen is linked to mother’s genotype and fetus’s genotype, & male fetuses are far more likely to be affected by teratogens than female fetuses
time of exposure
teratogens do more damage at specific developmental points, and embryonic period is more vulnerable than fetal period
critical period
fixed time period early in development during which certain experiences or events can have a long-lasting effect on development
prescription teratogens
antibiotics, antidepressants, hormones such as progestin and synthetic estrogen, Accutane
nonprescription teratogens
diet pills, high dosages of aspirin