what are the 4 periods of gestation?
what develops in the ectoderm?
brain and spinal cord (CNS)
what develops in the mesoderm?
muscles, skeletal system, circulatory system
what develops in the endoderm?
digestive system, lungs, and urinary tract
how long is the embryo in the embryonic period?
what happens in the germinal period?
fertilized egg travels to uterus
blastocyst implants on wall
placenta begins to form
what happens in the fetal period?
external genitalia begins to form
stimulation of sound and light
begins to feel pain
what is the age of viability?
what percent of time is the fetus usually awake?
11-16% of the time
at the end of the fetal period, how long is the fetus and how much will it weight approximately?
18-20 inches long and 6.5-7.5 lbs.
how much does the mother have to be dilated and effaced for expulsion?
10cm dilated and 100% effaced
how many weeks is full term?
what is the final step of birth?
what are the two main influences on development during gestation?
genetics and environment
what are the environmental factors that influence gestation?
what are teratogens?
disease or drugs that influence development
what are three demographics of the mother that influence gestation?
what are influences on development at birth?