Chapter 2: Heredity and Conception & Chapter 3: Prenatal Developmental
Chapter 2: Heredity and Conception & Chapter 3: Prenatal Developmental psy3803
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This 9 page Study Guide was uploaded by Gabriel Brooks on Tuesday February 16, 2016. The Study Guide belongs to psy3803 at Mississippi State University taught by Rebecca Armstrong in Summer 2015. Since its upload, it has received 58 views. For similar materials see Developmental Psychology in Psychlogy at Mississippi State University.
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Date Created: 02/16/16
Chapter 2: Heredity and Conception I. The Influence of Heredity on Development: The Nature of Nature Heredity- transmission of traits and characteristics from parents to child by means of genes. A. Chromosomes and Genes Chromosomes- rod-shaped structures that are composed of genes and found within the nuclei of cells Genes- basic unit of heredity Genes are composed of DNA (deoxcribronuclei acid) B. Mitosis and Meiosis Zygote- a new cell formed from the union of a sperm and an ovum (egg cell): a fertilized egg Mitosis- form of cell division in which each chromosome split lengthwise to double in number Meiosis- form of cell division in which each pair of chromosomes split and one member of each pair moves to the new cell. Mutation- sudden variation in a heritable characteristics, such as by an accident that affect the composition of genes C. Identical and Fraternal Twinning When a zygote splits Monozygotic (MZ) twins- identical twins Dizygotic (DZ) twins- fraternal twins D. Dominant and Recessive Trait Each member of a pair of genes is referred to as an allele. Homozygous- Having two identical alleles. Heterozygous- having two different alleles. Dominant trait- expressed traits Recessive trait- non-expressed traits when the genes involved have been paired with dominant genes. Carriers- a person who carries and transmits characteristics but does not exhibit them. II. Chromosomal and Genetic Abnormalities People normally have 46 chromosomes Children with more or fewer chromosomes usually experience health problems or behavioral abnormalities. A. Chromosomal Abnormalities Chromosomal abnormalities occur when children do not have the normal complement of 46 chromosomes. The risk of chromosomal abnormalities rises with age of the parents. 1. Down syndrome Down syndrome is usually caused by an extra chromosome on the 21 pair, resulting in 47 chromosomes A syndrome is a group of symptoms that characterize a disorder. 2. Sex-Linked Chromosomal Abnormalities Sex-linked chromosomal abnormalities- abnormalities that are transmitted from generation to generation, carried by a sex chromosome, usually an x sex chromosome Klinefelter syndrome- disorders found among males that is caused by an extra chromosome and is characterized by infertility Estrogen- a female sex hormone B. Genetic Abnormalities 1. PKU- recessive gene (both parents have to have genes) 2. Huntington Disease- a neurological disorder cause by dominant gene. The disorder is fatal. People may lose their intellectual function, personality disappears, and uncontrollable muscle movement. 3. Sickle cell- a recessive gene. This disease is most common in African Americans. 4. TaySachs Disease- a recessive gene. During this disease, the body central nervous system shuts down. Individuals become blind. 5. Cystic Fibrosis- excess of a really thick mucus. There is no cure for this disease. 6. Sex Linked Genetic Abnormalities- this is carried on the x chromosome. 7. Muscular dystrophy- disease that is a progressive wasting away of the muscles. C. Genetic Counseling Genetic counseling- advice concerning the probabilities that a couple’s child(ren) will show genetic abnormalities Prenatal testing- determines whether the fetus is carrying genetic abnormalities. *prenatal- before birth 1. Amniocentesis a procedure for examining fetal cells sloughed off into amniotic fluid to determine whether disorders are present 2. Chorionic Villus Sampling A method for the prenatal detection of genetic abnormalities prenatal detection of genetic abnormalities that samples the membrane enveloping the amniotic sac and fetus o Uterus- the hollow organ within females in which the embryo and fetus develop 3. Ultrasound Sound waves too high pitched for the human ear. Sonogram- procedure for using ultrasonic sound waves to create a picture of an embryo or fetus 4. Blood Tests AFP assay- a blood test that assesses the mother’s blood level of alpha-feta protein, a substance that is linked to fetal neural tube defects o AFP= alpha-feta protein III. Heredity and the Environment: Nature vs. Nurture A. Reaction Range Variability in the expression of inherited traits as they are influenced by environmental factors o Genotype- the genetic form of a person determined by environmental factors o Phenotype- actual, form of a person determined by heredity B. Canalization Tendency of growth rates to return to genetically determined patterns after undergoing environmentally induced change C. Genetic Environmental Correlation 1. Passive Correlation Correlation between the genetic endowment parents give their children and the environments in which they place their children in. 2. Evocative Correlation Correlation between the child’s genetic endowment and the responses the child elicits from other people 3. Active Correlation Correlation between the child’s genetic endowment and the choices the child makes about which environments they will seek Niche-picking- choosing environmental conditions that foster one’s genetically transmitted abilities and interests 4. The Epigenetic Framework Epigenesis- development reflects continual bidirectional exchange between one’s genotype and one’s environmental conditions D. Twin Studies: Looking in the Genetic Mirror Autism- developmental disorder characterized by failure to relate to others, communication problems, intolerance, of change, and ritualistic behavior E. Adoption studies When children are separated from their natural parents at an early age and reared by adoptive parents who provide special opportunities for sorting out nature and nurture IV. Conception: Against All Odds Conception- union of a sperm and an ovum A. Ova Fallopian tube- a tube that the ova travels through from an ovary to the uterus Endometrium- inner lining of uterus Corpus luteum- where the egg is released from the ovary Zona pellucid- outer layer of uterus B. Sperm Cells Spontaneous abortion- unplanned, accidental abortion V. Infertility and Assisted Reproductive Technology A. Cause of Infertility Motility- self- propulsion Pelvic inflammatory disease- infection of the abdominal region that may have various causes and may impair fertility Endometriosis- inflammation of endometrial tissue sloughed off into the abdominal cavity rather than out of the body during menstruation B. Helping People with Fertility Problems Become Parents 1. Artificial Insemination Injection of sperm into the uterus to fertilize an ovum 2. In Vitro Fertilization In vitro fertilization- fertilization of an ovum in a laboratory dish 3. Donor IVF The transfer of a donor’s ovum, fertilized in a laboratory dish, to the uterus of a woman Embryonic transplant- the transfer of an embryo from the uterus of one woman to another 4. Surrogate Mother Mothers who carry babies for other women Chapter 3: Prenatal Development Prenatal development- divided into three stages o Germinal stage- first two weeks (the period from conception to implantation) o Embryonic stage-3-8 weeks o Fetal stage- 3 months until birth *division starts 24 hours after conception *implantation I. The Germinal Stage: Wanderings Implantation zygote blastocyst Embryonic disk(inside)- has two distinct layouts Blastocyst(trophoblast)- o Produces blood cells, initially o Develops into the umbilical cord o Develops into the amniotic sac o Then becomes the chorion, which will line the placenta o a. Without Visible Means of Support II. The Embryonic Stage *from implantation – 2 months Cephalocaudal- from head to tail Proximodistal- from the inner part(or axis) of the body outward During the embryonic stage the out layer of the cells of the embryonic disk or ectoderm, develops into the nervous system, sensory organs, nails, hair, and teeth, and the outer layer of the skin. o Ectoderm- The outermost cell layer of the newly formed embryo from which the skin and nervous system develops (sensory organs, nails, hair, and teeth, and the outer layer of the skin) o Endoderm- Forms the digestive and respiratory system o Mesoderm- develops the excretory reproductive, and circulatory system, the muscles, the skeleton, and the inner layer of the skim a. Sexual Differentiation Woffian (male) Mullerian (female) i. Sex Hormones and Sexual Differentiation Prenatal sexual differentiation requires hormonal influences as well as genetic influences. o Androgens- male sex hormones, are critical in the development of male genital organs o Once testes have developed in the embryo, they begin to produce androgens. The most important of these is testosterone. o Testosterone spurs the differentiation of the male ( Wolffian) duct system and remains involved in sexual development and activity for a lifetime b. The Amniotic Sac: A Shock Absorber Amniotic sac is in the uterus o Is surrounded by a clear membrane and contains amniotic fluid o The mother is connected to the blood vessels o Continues to secretes hormones Hormones that prepare mom’s breast *1-3ft (umbilical cord) c. The Placenta: A Filtration System Is connected to the embryo and the umbilical cord Mother is connected by the blood vessels Continues to secrets hormones o Hormones that prepare thee mother’s breast *1-3ft (Umbilical cord) III. The Fetal Stage begins the 3 month until birth rapid growth male fetus move more often than a female’s th *growth slows down 7 month 2d trimester o Develops fine, downy hair (lanugo) 3dtrimester o Turns up-side down IV. Environmental Influences on Prenatal Development a. Nutrition Malnutrition- have a chance of giving birth to a low birth weight Stillbirth- death of a born baby i. What Should a Pregnant Woman Eat? ii. How Much Weight Should a Pregnant Woman Gain? Pregnant women should gain 25-35 pounds b. Teratogens and Health Problems of the Mother Teratogens- environmental influences that can damage the embryo or fetus i. Critical Periods of Vulnerability Critical period- a period during which an embryo is particularly vulnerable to a certain teratogen ii. Sexually Transmitted Infections Syphilis- cause miscarriages, stillbirth iii. The Flu Affects mothers’ respiratory system iv. Rubella Viral infection v. Pre-Eclampsia Dangerously high blood pressure Affected women often have premature babies vi. Rh Incompatibility A condition in which antibodies produced by the mother are transmitted to the child, possibly causing brain damage or death c. Environmental Hazards i. Maternal Stress Stress prolongs labor
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