Chapter 3: Prenatal Development Flashcards
3 periods of prenatal development (zygote, embryo, fetus) and long each period lasts. Be able to describe the major events that occurs during in each phase.
Zygote (conception to 2 weeks) - fertilization, formation of blastocyst,
Embryo (6 weeks; 2 to 8 weeks after conception) - most rapid prenatal changes, all groundwork laid for all body structures and internal organs, heart begins to beat.
Fetus (30 weeks; 2 months to birth) - growth and finish.
Blastocyst? how does it differ from zygote?
zygote is just when sperm meets the egg. blastocyst - 60 to 70 cells that forms a hollow, fluid-filled ball.
During what month of pregnancy can a fetus suck its thumb
8th month
explain how the fetus plays a role in its own development. How does the fetus’s own movements affect the structure of the fetus’s body. It’s developing nervous system.
quickening (kicking) occurs at this stage but the mother does not feel it until later in the development. Helps with development with the nervous system.
at the end of of which trimester are nearly all the neurons in place?
end of second trimester
What is myelination? what are glial cells and what is their function? when do they stop developing?
glial cells - support and feed the neurons, continue to increase at a rapid rate throughout the remaining months of pregnancy (after second trimester), as well as after birth. ask teach.
what and when is the age of viability?
point at which the baby can first survive, occurs sometime between 22 and 26 weeks.
When can fetuses touch, smell, taste, hear, see? When can they differentiate voices?
touch - 7.5 weeks smell - 11 to 13 weeks taste - 11 to 13 weeks hearing - 21 weeks, 23-36 can distinguish voices see - 26 weeks
When does the fetus receive maternal antibodies. Prior to what moth would a baby born prematurely be susceptible to infection?
8th month, immune system doesn’t work until several months after birth.
teratogens. Which organ system has the longest sensitive period to teratogens. structural defects most likely to occur. least likely?
any environmental agent that causes damage during the prenatal period.
brain and eyes have longest.
limbs and palate have short.
embryonic period most sensitive.
Why are teen mothers at greater risk than older mothers for prenatal complications?
low-income, stress, poor nutrition, and health problems are common. Also afraid to seek medical care or no access because of lack of health insurance.
