modules 36-38: prenatal development and infancy Flashcards
a fetus typically reaches the age of viability at the prenatal age of:
22 weeks
if a mother is anxious and tense during pregnancy, how can that affect fetal development?
the infant will sleep and eat poorly once born.
what are some consequences of undernourished pregnant mothers?
- underweight babies
- babies more susceptible to disease
- adverse impact on mental development
what system in the baby becomes especially sensitive as a result of the chemical changes produced by the mother’s emotional state?
autonomic nervous system
what is conception?
when a male’s sperm cell penetrates a female’s egg cell
what are chromosomes?
rod-shaped structures that contain hereditary information
what are genes?
smaller units through which genetic information is transmitted
how many different genes do humans have?
more than 25000
what is a zygote?
a one-celled entity, resulting from fusion of egg and sperm
what is the germinal period?
two weeks after conception;
before zygote is implanted in the uterine wall
describe the embryonic period.
Week 2 to week 8
Organs are recognizable
face begins to develop ( nose, eyes, mouth)
what is the age of viability?
the point at which a baby can survive if born premature ( 22 weeks)
what is a sensitive period?
the period when organisms are susceptible to certain kinds of stimuli
who are “problem infants”?
infants who are born before week 38
what is Tay-Sachs disease?
the body cannot break down fat, mostly found in Eastern European ancestry
what is Down Syndrome?
zygote receives an extra chromosome at the point of conception, often related to the mother’s age
what are teratogens?
Environmental agents ( drugs, chemicals, viruses) that can harm the baby during prenatal development
what is development?
change over time
describe cell division (mitosis)
begins 24-36 hours after the zygote is created
describe cell migration.
cells moving from point of origin to other places in the developing zygote.
describe cell differentiation.
process that transforms unspecialized stem cells to about 350 different types of cells. ( to eventually become organs and other body parts)
describe cell death (apoptosis)
selective cells are thrown away ( cells are selected to die between your fingers to create the spaces)
what are embryonic stem cells?
cells with no fixed function
describe the fetal period.
8 weeks of age to birth
increasing level of growth, behavior, sensory experience
internal organs have mostly developed, sex differentiation has begun
