integ: devpsych (prenatal development)

Fertilization

marks the beginning of development where the sperm and ovum combine to create a zygote in the fallopian tube

Fertile Window

• unpredictable time during which conception is possible

• Maturation of sex cells must occur prior intercourse for conception to be possible

• Women → Menarche

• Men → Nocturnal Emission

Ovulation

rupture of a mature follicle which occurs every 28 days until menopause

Zygote

duplicates itself through the process of cell division to produce all cells that make up a baby

Dizygotic Twins

• fraternal twins that result from the fertilization of 2 separate eggs by 2 sperms

• Tend to run in families and passed down from a woman’s mother

• Result of multiple eggs being released at one time

Monozygotic Twins

identical twins that result from the cleaving of 1 fertilized egg

Twin-to-twin Transfusion Syndrome

condition in which nutrients are shared unequally as a result of an abnormal formation of blood vessels in the placenta

Mitosis

• process by which somatic cell’s nucleus duplicates itself to form two new cells

• Genetic identity of the parent cell is preserved, leading to minimal genetic variation among daughter cells

• Results in the formation of two identical diploid daughter cells

• “Copy and stay the same”

• ex: When you get a cut, your skin heals using mitosis, Growing taller → more body cells made by mitosis

meiosis

• specialized form of cell division that is involved in the production of gametes for sexual reproduction (sperm and egg)

• Introduces genetic diversity and results in genetically unique daughter cells

• Results in the formation of four non-identical haploid daughter cells

• “Mix and reduce”

• ex: Testes produce sperm using meiosis, Ovaries produce eggs using meiosis

• This is why children are genetically different from their parents

Gene

• segments of DNA that contain the instructions for building and maintaining an organism

• Help cells to reproduce themselves and help manufacture the proteins that maintain life

Chromosomes

threadlike structures that come in 23 pairs and contain DNA

Deoxyribonucleic Acid (DNA)

a complex molecule that contains genetic information

Mutation

a permanent alteration in the DNA sequence of a gene; can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection

Proteins

building blocks of cells and regulators that direct the body’s processes

Human Genome

• reference point that shows the location of all human genes

• complete set of DNA in a human.

• It’s like your body’s instruction manual that tells your cells how to grow, function, and stay alive.

Methylation

tiny atoms attach themselves to the outside of a gene resulting in certain genes becoming turned on or off

Susceptibility Genes

genes that make the individual more vulnerable to specific diseases or accelerated aging

Longevity Genes

genes that make the individual less vulnerable to certain diseases and more likely to live to an older age

Sex-Linked Genes

• genes that determine an individual's sex / gender at birth; twenty-third pair of chromosomes

• XX: Female sex chromosomes

• XY: Male sex chromosomes

Autosomes

• chromosomes that are not related to sexual expression

• They are your body’s “regular chromosomes” that control most of your traits

X-linked Inheritance

• when a mutated gene is carried on the X chromosome

• when a trait or disorder is caused by a gene on the X chromosome.

• More commonly expressed in males because they lack a second X chromosome to mask the effects of the recessive allele

• Females carrying one normal and one mutated X-linked allele are typically carriers and may not express the disorder

Mendel's laws of inheritance

include law of dominance, law of segregation, and law of independent assortment

Allele

• two or more alternative forms of a gene that occupy the same position on paired chromosomes and affect the same trait

• different versions of the same gene that cause variations in traits.

• you always have 2 alleles for each gene

ex:

BB	Brown eyes

Bb	Brown eyes (dominant wins)

bb

Blue eyes

Homozygous

possessing two identical alleles for a trait

Heterozygous

possessing two different alleles for a trait

Dominant Inheritance

pattern of inheritance in which, when a child receives different alleles, only the dominant one is expressed

Dominant Gene

• an allele that is expressed in the phenotype even when only one copy is present in the genotype (heterozygous condition)

• a gene that shows its effect even if only one copy is present.

• It “wins” over the other gene

Recessive Inheritance

pattern of inheritance in which a child receives identical recessive alleles, resulting in expression of a nondominant trait

Recessive Gene

• an allele that is expressed in the phenotype only when two copies are present in the genotype (homozygous condition)

• a gene that only shows its effect if both copies are the same

Polygenic Inheritance

• inheritance of traits that are controlled by multiple genes, each with a small additive effect

• multiple genes work together to control one trait.

Multifactorial Transmission

• a phenomenon by which environmental experience modifies the expression of the genotype for most traits

• when a trait or condition is caused by both genes AND environmental factors.

• It’s not just your genes—your lifestyle and environment also matter

Genotype

• person’s genetic heritage; the actual genetic material

• It’s what’s in your DNA

• ex: BB, Bb, bb

Phenotype

• the observable, physical, and biochemical traits of an organism
  It’s how your genes show up physically

• ex: Brown eyes, Blue eyes, Tall or short

Epigenesis

• an organism develops step by step, with structures forming gradually over time.

• gradual development of an organism from a simple beginning

• how the body develops

epigenetics

• mechanism that turns genes on or off and determines functions of body cells

• Genes are turned off or on as they are needed by the developing body or when triggered by the environment

• Explains why identical twins, even though their genomes are identical, do not look exactly the same

Genetic Imprinting

• occurs when the expression of a gene has different effects depending on whether the mother or the father passed on the gene

• when only one copy of a gene is active, depending on whether it came from your mother or father.

• You inherit two copies of a gene, but one is “turned off”

Down Syndrome (Trisomy 21)

• extra copy of chromosome 21

• associated with intellectual disabilities, distinctive facial features, and an increased risk of certain health issues

Cri-du-chat Syndrome

• deletion on the short arm of chromosome 5

• may have a distinctive cry resembling a cat

Edwards Syndrome (Trisomy 18)

• extra copy of chromosome 18

• associated with severe intellectual disabilities, congenital heart defects, and abnormalities in various organ systems

Patau Syndrome (Trisomy 13)

• extra copy of chromosome 13

• severe developmental and physical abnormalities, including intellectual disabilities, heart defects, and cleft lip and palate

Prader-Willi Syndrome

• genes on chromosome 15 are missing or inactive

• intellectual disabilities, obesity, and behavioral issues

Alpha, Antitrypsin Deficiency

• mutation in chromosome 14

• enzyme deficiency that can lead to cirrhosis of the liver, emphysema, and degenerative disease in middle age

Alpha Thalassemia

• mutation in chromosome 16

• severe anemia that reduces the ability of the blood to carry oxygen, and all affected infants are stillborn or die soon after birth

Beta Thalassemia (Cooley’s Anemia)

• mutation in chromosome 11

• severe anemia resulting in weakness, fatigue, and frequent illness; usually fatal in adolescence or young adulthood

Cystic Fibrosis

• mutation in chromosome 7

• overproduction of mucus which collect in the lungs and digestive tract; children do not grow normally and usually do not live beyond the age of 30

Anencephaly

• influenced by a combination of environmental and genetic factors associated with the formation and closure of the neural tube during embryonic development

• absence of the cerebral hemispheres and the overlying skull and scalp; infants are stillborn or die soon after birth

Spina Bifida

• mutation in chromosome 11; the neural tube / spinal column fails to close properly

• muscle weakness or paralysis, loss of bladder and bowel control, hydrocephalus, and mental retardation

Phenylketonuria (PKU)

• caused by the inability to metabolize the amino acid, phenylalanine

• intellectual disability / hyperactivity if left untreated

Polycystic Kidney Disease

• Infantile form: enlarged kidneys, leading to respiratory problems and congestive heart failure

• Adult form: kidney pain, kidney stones, and hypertension resulting in chronic kidney failure

Sickle-cell Anemia

• a recessive gene causes the red blood cell to become a hook-shaped “sickle” that cannot carry oxygen properly

• limits the body’s oxygen supply; joint swelling, and heart / kidney failure

Tay-Sachs Disease

deceleration of mental and physical development caused by an accumulation of lipids in the nervous system

Diabetes

body doesn't produce enough insulin, which causes abnormal metabolism of sugar

Huntington’s Disease

central nervous system deteriorates, producing problems in muscle coordination and mental deterioration

Angelman Syndrome

absence or dysfunction of maternal genes on chromosome 15

developmental delays, seizures, and a happy demeanor

Turner Syndrome (XO)

• occurs in females with a single X chromosome (45, X)

• short stature, webbed neck, and infertility

Klinefelter Syndrome (XXY)

affects males with an extra X chromosome (XXY)

reduced fertility, gynecomastia (enlarged breasts), and other physical characteristics

Triple X Syndrome (XXX)

• occurs in females with an extra X chromosome (47, XXX)

• most individuals have no or mild symptoms, but some may experience learning difficulties, menstrual irregularities, and mental retardation

XYY Syndrome

• affects males with an extra Y chromosome (47, XYY)

• tall structure, low IQ, especially verbal

• expansion of a particular region on the X chromosome

• minor to severe mental retardation, delayed speech and motor development, speech impairments, and hyperactivity

Duchenne Muscular Dystrophy

• mutation in the X sex chromosome

• fatal disease usually found in males; marked by muscle weakness, minor mental retardation, respiratory failure and death in young adulthood

Behavior Genetics

field that seeks to discover the influence of heredity and environment on individual differences in human traits and development

Heritability

statistical estimate of contribution of heredity to individual differences in a specific trait within a given population

Concordant

tendency of twins to share the same trait or disorder

Twin Study

behavioral similarity of identical twins is compared with the behavioral similarity of fraternal twins

Adoption Study

seek to discover whether the behavior and psychological characteristics of adopted children are more like those of their adoptive parents or more like those of their biological parents

Reaction Range

• Range of potential expressions of a hereditary trait

• Depends on environmental opportunities and constraints and a person’s behavior

Canalization

• Illustrates how heredity restricts the range of development for some traits

• Strongly programmed by genes and there is little opportunity for variance in their expression

• It would take an extreme change in environment to alter their course

Genotype-Environment Interaction

• Effects of similar environmental conditions on genetically different individuals

• Genetically similar children often develop differently depending on their home environments

• Analogous to diathesis-stress model

Genotype-Environment Correlations

Tendency of certain genetic and environmental influences to reinforce each other

Passive

• when an individual’s environment is correlated with the genetic makeup they inherit from their parents

• The environment reacts to you

• ex: A naturally cheerful baby gets more positive attention from parents, A child with reading talent is encouraged by teachers

Evocative

• when an individual's genetically influenced characteristics evoke specific responses from others in their environment

• You evoke reactions from your environment

• ex: A talkative child makes friends easily → people include them in activities, A shy child receives more reassurance from adults

Active

• when individuals seek out or create environments that are compatible with their interests (niche-picking)

• You actively choose environments that fit your genes

• ex: A genetically musical child joins a band class, A naturally athletic teen chooses soccer practice

Nonshared Environment

• Unique environment in which each child in a family grows up

• Consists of distinctive influences or influences that affect one child differently than another

• accounts for most of the difference

• Children’s genetic differences may lead parents to react to them differently and treat them differently

Prenatal Development

gestation that takes place in three stages: germinal, embryonic, and fetal

Gestation

period of development between conception and birth

Gestational Age

age of an unborn baby dated from the first day of an expectant mother’s last menstrual cycle

Cephalocaudal Principle

• dictates that development proceeds from the head to the lower part of the trunk

• Babies develop control of head and upper body first, then arms and legs.

Proximodistal Principle

dictates that parts of the body near the center develop before the extremities

36th

At the what hour of fertilization, the zygote enters a period of rapid cell division and duplication (mitosis)

3rd day (72nd Hour)

By the what, the cell has divided into 16 → 32 cells

4th

By the what day, 32 → 64 → 128 cells (blastocyst)

4th – 5th Day

fertilized ovum makes its way through the fallopian tube to the uterus

6th – 7th Day

blastocyst begins to implant itself in the uterine wall through the process of implantation

Blastocyst

fluid-filled sphere, which floats freely in the uterus

Embryonic Disk

thickened cell mass from which the embryo begins to develop

Implantation

attachment of the blastocyst to the uterine wall

11th – 15th Day

• process of implantation concludes which marks the beginning of the embryonic stage

• Other parts of the blastocyst begin to develop into organs that will nurture and protect development in the womb

Amniotic Sac

fluid-filled membrane that encases the developing embryo

Placenta

allows oxygen, nourishment, and wastes to pass between mother and embryo

Umbilical Cord

connects a developing fetus to the placenta, allowing for the exchange of nutrients, oxygen, and waste products between the fetus and the mother

Endoderm

inner layer of cells, which will develop into the digestive and respiratory systems

Mesoderm

middle layer, which will become the circulatory system, bones, muscles, excretory system, and reproductive system

Ectoderm

outermost layer, which will become the nervous system and brain, sensory receptors, and skin parts

Organogenesis

organs and major body systems (respiratory, digestive, and nervous) develop rapidly

Spontaneous Abortion

natural expulsion from the uterus of an embryo that cannot survive outside the womb (miscarriage); often occurs during the first trimester

Stillbirth

miscarriage that occurs after 20 weeks of gestation

3rd Week

neural tube that eventually becomes the spinal cord forms

21 Days

eyes begin to appear

24 Days

cells for the heart begin to differentiate

4th Week

• urogenital system becomes apparent

• Arm and leg buds emerge

• Four chambers of the heart take shape

• Blood vessels appear