PSYCH 250 Lecture Notes - Lecture 4: Neural Tube, Fetus, Endoderm
Document Summary
Pregnancy lasts a total of 38 weeks. This is what becomes the placenta and umbilical cord) By 8th week, embryo is 1" and weighs 1/30th of an ounce. Fetus is 3 months, 3 ozes and 3 inches. 95% chance of survival by this point. Age of viability - age at which a fetus can survive if born early (22 weeks) Only 20% under 1 pounds survive. By 28 weeks (3 lbs), survival rate is 95% Teratogen - any agent or condition that can impair prenatal development and result in birth defects or death. Ex. diseases (e. g. rubella), lifestyle choices (e. g. diseases (e. g. rubella), lifestyle choices (e. g. drug use), medications. Critical period is the time of greatest vulnerability (for each body structure) Birth defects affect 5%-8% of live births. 20% of all defects are of unknown origin. Ethnicity, sex (males are at a greater risk) Tobacco 12% of pregnant women smoked and a common side effect was low.
