Life-span development chap 4 notes

I. Prenatal Development A. Germinal Period - Conception to 2 weeks 1. Creation of the zygote 2. Continued cellular telephone form 3. Implantation - attachment of the zygote to the uterine wall (10 shape up later founding) * Blastocyst - inner cells (embryo) * Trophoblast - outer layer (placenta/umbilical cord cord cord - life plump fors establishments) B. Embryonic Period - 2 to 8 weeks after conception 1. Cell differentiation intensifies, support systems for cells form and organs come forths 2. committed zygote becomes embryo * hypoblast (digestive/respiratory systems) * Mesoderm (circulatory system, bones, muscles, excretory system, rejoinder system) * Ectoderm (nervous system sensory receptors, skin parts such as vibrissa and nails) C. Fetal Period - 8 weeks after conception until bring forth 1. Fetal size increases and organs start functioning 2. Reflexes appear and thither is sexual differentiation D. Miscarriage and Abortion 1. most(prenominal) occur within 1st t rimester (chromosomal abnormalities) 2. 15-20% pregnancies expiry in still birth * male fetuses more likely to miscarry 3. Abortions legal in U.S. until stamp out of 2nd semester * 1 spontaneous stillbirth for every 2 births * cast-off(prenominal) pregnancies stressful for woman regardless of how it is indomitable * Psychological effects of abortion include relief and ill-doing (usually mild and disappears) * Women with previous psychiatrical problems more likely to look adverse effects II. Teratology and Hazards to Prenatal Development A. Teratogen - whatever operator that yards birth defects 1.

Environmental Hazards * Radiati on (chromosomal abnormalities) * Pollutants ! & toxic wastes (lead, pesticides, ascorbic blistering dioxide, mercury dangerous to fetus) * Drugs Thalidomide - prescribed in 1960s for morning affection (deformed babies) Cocaine/heroin (addiction/withdrawal symptoms/neurological defects) Alcohol (fetal intoxicant syndrome) Smoking (low birth weight, ADHD, wrong births, SIDS) Marijuana, antibiotics, excessive vitamins, antihistamines, aspirin, diet pills poisonous 2. Maternal diseases can cross the placenta barrier and cause birth defects - Rubella (German measles)... If you want to get a bountiful essay, bless it on our website: BestEssayCheap.com

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