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Conception and prenatal development.

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  1. 1. Prenatal Development
  2. 2. Genes & Chromosomes <ul><li>Gametes </li></ul><ul><li>Male & female reproductive cells </li></ul><ul><li>Zygote </li></ul><ul><li>The new cell formed at conception </li></ul><ul><li>Genes </li></ul><ul><li>Basic units of genetic information </li></ul><ul><li>DNA </li></ul><ul><li>The biochemical basis of heredity </li></ul><ul><li>Chromosomes </li></ul><ul><li>Thread-like structures in the nucleus of a cell which contain genetic material </li></ul>
  3. 3. The Human Genome <ul><li>Genetic Compliment </li></ul><ul><li>Over 25,000 genes in human gename </li></ul><ul><li>DNA Creates Proteins </li></ul><ul><li>DNA is not the blueprint for who & what you are </li></ul><ul><li>Contribution of the Parents </li></ul><ul><li>Each parent gives 23 chromosomes at conception </li></ul>
  4. 4. Conception <ul><li>Union of Egg & Sperm </li></ul><ul><li>Produces the zygote </li></ul><ul><li>Zygote grows through cellular division </li></ul><ul><li>Specific genes on chromosomes determine what the cells of the body will do </li></ul>
  5. 5. Multiple Births <ul><li>Statistics </li></ul><ul><li>1 in 86 Caucasians & 1 in 70 African Americans </li></ul><ul><li>Twins </li></ul><ul><li>Monozygotic </li></ul><ul><li>Identical twins </li></ul><ul><li>Dizygotic </li></ul><ul><li>Fraternal twins </li></ul>
  6. 6. Basic Genetics <ul><li>Dominant Trait </li></ul><ul><li>Trait expressed when 2 traits compete </li></ul><ul><li>Recessive Trait </li></ul><ul><li>Trait that expresses itself only when paired with another of the same kind </li></ul><ul><li>Genotype </li></ul><ul><li>Underlying genetic material </li></ul><ul><li>Phenotype </li></ul><ul><li>Observable trait </li></ul><ul><li>Heterozygous </li></ul><ul><li>When genes for characteristics differ </li></ul><ul><li>Homozygous </li></ul><ul><li>When genes for characteristics are the same </li></ul><ul><li>Polygenetic Inheritance </li></ul><ul><li>When a combination of genes is responsible for a particular trait </li></ul><ul><li>X-linked Genes </li></ul><ul><li>Recessive genes on the X chromosome </li></ul>
  7. 7. Behavioral Genetics <ul><li>Study of the Effects of Genetics on Behavior </li></ul><ul><li>99% of all gene sequences is shared by ALL humans </li></ul><ul><li>Genetics produces predispositions </li></ul><ul><li>Personality Traits </li></ul><ul><li>Many personality traits have genetic links: shyness, sociability, moodiness, temperament, assertiveness, depression, AD/HD, schizophrenia </li></ul>
  8. 8. Heredity & Environment <ul><li>Heredity & Environment Work Together </li></ul><ul><li>Genetics is under the influence of the environment </li></ul><ul><li>e.g. height, language, & temperament </li></ul><ul><li>Interaction of Many Factors </li></ul><ul><li>Many traits reflect multifactoral transmission </li></ul><ul><li>Determined by a combination of genetic & environmental factors </li></ul><ul><li>Question is: How much is nature & how much is nurture? </li></ul><ul><li>All data suggests it’s a combination </li></ul>
  9. 9. Personality <ul><li>Genetic Factors </li></ul><ul><li>Genetic roots to many traits </li></ul><ul><li>The “Big Five” </li></ul><ul><li>Twin Studies </li></ul><ul><li>Cultural Differences </li></ul><ul><li>Social determinants </li></ul><ul><li>Underlying social temperament </li></ul><ul><li>Predispositions toward particular philosophies </li></ul>
  10. 10. Psychological Disorders <ul><li>Schizophrenia </li></ul><ul><li>Tends to run in families </li></ul><ul><li>Monozygotic twins have 50% chance of developing it </li></ul><ul><li>Sensitivity to stress </li></ul><ul><li>Other Disorders </li></ul><ul><li>Major depression, alcoholism, autism, AD/HD </li></ul><ul><li>Heredity & Environment </li></ul><ul><li>Influences of each changes over person’s life-time </li></ul>
  11. 11. Prenatal Growth <ul><li>Fertilization </li></ul><ul><li>The union of the egg & sperm </li></ul><ul><li>Blastocyst </li></ul><ul><li>The fertilized egg as it begins to germinate </li></ul><ul><li>Fetus </li></ul><ul><li>A developing child from 8 weeks on </li></ul><ul><li>Teratogen </li></ul><ul><li>A factor that produces birth defects </li></ul>
  12. 12. Stages of Prenatal Development <ul><li>Germinal Stage: Fertilization to 2 weeks </li></ul><ul><li>Zygote divides turning into a blastocyst that implants into uterine wall </li></ul><ul><li>Embryonic Stage: 2 weeks to 8 weeks </li></ul><ul><li>The 3 dermal layers begin developing; neurogenesis begins at over 100,000 per minute </li></ul><ul><li>Fetal Stage: 8 weeks to birth </li></ul><ul><li>Major organs begin differentating, brain begins developing; sexual differentiation </li></ul>
  13. 13. Pregnancy Problems <ul><li>Infertility </li></ul><ul><li>15% have fertility problems </li></ul><ul><li>A negative correlation with age </li></ul><ul><li>Different causes </li></ul><ul><li>Illicit drugs, cigarettes, hormone imbalances, stress </li></ul><ul><li>Treatment </li></ul><ul><li>Fertility drugs, artificial insemination, IVF </li></ul><ul><li>Miscarriage & Abortion </li></ul><ul><li>15% - 20% of pregnancies end in miscarriage </li></ul><ul><li>Abortion is voluntary ending of pregnancy </li></ul><ul><li>Difficult choice but it doesn’t produce long-lasting emotional problems </li></ul>
  14. 14. Threats to Development <ul><li>Taratogens </li></ul><ul><li>Drugs, chemicals, viruses, etc. </li></ul><ul><li>Timing & quantity of the exposure is important </li></ul><ul><li>Especially problematic during periods of rapid prenatal development </li></ul><ul><li>Poverty increases the chances of exposure </li></ul>
  15. 15. Threats to Development <ul><li>Mother’s Diet </li></ul><ul><li>Developing fetus needs the appropriate nutrients </li></ul><ul><li>Mother’s Age </li></ul><ul><li>Under 16, over 30, & over 40 greatest risk </li></ul><ul><li>Down’s Syndrome in 1 of 100 over 40 births </li></ul><ul><li>Adolescent pregnancies more likely to be premature & still-born </li></ul><ul><li>Prenatal Support </li></ul><ul><li>Younger mothers generally have adverse social & economic factors </li></ul><ul><li>Mother’s Health </li></ul><ul><li>Rubella prior to 11 th week can produce blindness, deafness, heart defects, or brain damage </li></ul><ul><li>Chicken pox & mumps increase miscarriage </li></ul><ul><li>Some STD can be transmitted to fetus </li></ul><ul><li>Mother’s Drug Use </li></ul><ul><li>Some OTC remedies can cause problems </li></ul><ul><li>Mother’s Use of Alcohol & Tobacco </li></ul><ul><li>FAS in 1 of 750 births of alcohol users </li></ul><ul><li>Smoking reduces oxygen content & increases carbon monoxide </li></ul>
  16. 16. Threats to Development <ul><li>Father’s Effects </li></ul><ul><li>2 nd hand smoke affects the mother’s health which affects the fetus </li></ul><ul><li>Use of alcohol & illicit drugs can damage sperm </li></ul><ul><li>Physical & emotional abuse affects the stress level of the mother </li></ul>
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