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 air division 3. Implantation - attachment of the zygote to the uterine wall (10 maturate later founding) * Blastocyst - inner cells (embryo) * Trophoblast - outer layer (placenta/ umbilical cord cord - life clogs formations) B. Embryonic Period - 2 to 8 weeks after conception 1. Cell differentiation intensifies, support systems for cells form and organs protrudes 2. committed zygote becomes embryo * entoblast (digestive/respiratory systems) * Mesoderm (circulatory system, bones, muscles, excretory system, rejoinder system) * Ectoderm (nervous system sensory receptors, skin parts such as sensory hair and nails) C. Fetal Period - 8 weeks after conception until give up 1. Fetal size increases and organs start functioning 2. Reflexes appear and thither is sexual differentiation D. Miscarriage and Abortion 1. roughly occur within 1st trimester (chromo somal abnormalities) 2. 15-20% pregnancies expiry in still receive * male fetuses more likely to miscarry 3. Abortions legal in U.S. until stamp out of 2nd semester * 1 spontaneous spontaneous abortion for every 2 births * cast-off(prenominal) pregnancies stressful for woman regardless of how it is end * Psychological effects of abortion include relief and guilty conscience (usually mild and disappears) * Women with previous psychiatrical problems more likely to go steady adverse effects II. Teratology and Hazards to Prenatal Development A. Teratogen - whatever divisor that yards birth defects 1.

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

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