Chapter 3 - Prenatal Development, Birth And The Newborn Flashcards
Prenatal development
The changes that transform a fertilized egg into newborn human
Prenatal development typically takes 38 weeks
Three stages of pregnancy
Zygote (1 to 2 weeks)
Embryo (3 to 8 weeks)
Fetus (9 to 38 weeks)
What occurs during the period of the zygote?
Growth and movement from fallopian tube to uterus
Within hours of conception the cells begin to divide out a rapid pace promoting growth
Blastocyst
Zygote resembles a hollow ball consisting of 100 to 200 cells
Inner layer (mass) is embryo Outer layer consists of the placenta, umbilical cord, and amino sac
Implantation
The final stage of the zygote (blastocyst burrows into the uterine wall and establishes connection with the mother’s blood vessels)
Day 7-14
Sends hormonal signals to prevent menstruation
What occurs during the period of the embryo?
Body structures and internal organs develop
Once blastocyst is fully embedded in uterine wall the embryo forms
During this rapid period of growth and specialization, embryo is highly Suspectible to environmental influences
Three layers of the embryo
Ectoderm: hair,skin, nervous system
Mesoderm: muscles, bones, and circulatory system
Endoderm: digestive system, lungs
Structure of the embryo
Placenta, amniotic sac, amniotic fluid, umbilical cord
Placenta
Organ that connects the amniotic sac to uterus
Amniotic Sac
Sac in which the embryo rests
Amniotic fluid
Cushions embryo and contains constant temperature
Umbilical cord
Houses blood vessels that join embryo to placenta
Neural tube
One end of the tube is the brain and the other is the spine
Sufficient levels of folic acid or needed to ensure neural tube closes or else Spina Bifida occurs
What occurs during the period of the fetus?
Baby becomes much larger (1 ounce to 7–8 pounds)
Bodily systems begin to work
Second trimester
Months 4 to 6
Rapid growth, refining reproductive system and Brain functions, mom can feel quickening
Third trimester
Months 6 to 9/10
Respiratory system matures, begins to practice breathing (lungs are last)
And continues to develop, fetus puts on weight
Age of viability
By 22 to 28 weeks of fetus has a chance of survival but lungs are under developed and the fetus lacks insulation layer (fat layer)
Fetal behavior
Fetus begins regular cycles of movement
Difference is an activity predict infant temperament
(More active= unhappy and difficult baby less active= happy and easy to soothe baby)
Fetal learning
Fetus is learning and already using some senses
Hearing, taste