Chapter 2: Biological and Environmental Foundations and Prenatal Development Flashcards
What is a dominant gene?
gene that is always expressed regardless of the gene it is paired with
What is a recessive gene?
gene that is expressed only if paired with another recessive gene
Genetic Disorders
Name 2 dominant-recessive disorders.
Huntington’s Disease (dominant)
Phenylketonuria (PKU) (recessive)
Genetic Disorders
What are X-linked disorders?
genetic disorder carried on the X chromosome
Genetic Disorders
Who is more likely to get X-linked disorders?
males are more likely because they only have one X chromosome, and there is no other chromosome to override the disorder on their X chromosome
Genetic Disorders
Name 2 X-linked disorders.
Hemophilia
Color Blindness
Genetic Disorders
What are chromosomal abnormalities?
result from cell reproduction (mitosis and meiosis), or from damage after reproduction
Genetic Disorders
Name 3 chromosomal abnormalities.
Down Syndrome (3rd chromosome on 21st pair)
Turner Syndrome (only females, only one X chromosome)
Klinefelter Syndrome (only males, have an extra X chromosome)
Genetic Disorders
What are mutations?
sudden change or abnormality in structure of the gene that occurs spontaneously or due to exposure to environmental factors
Genetic Disorders
How might a mutated chromosome affect pregnancy?
- about half of all fertilized eggs have some level of mutated chromosomes
- the developing zygote or embryo is miscarried because the level of mutation is so severe that they embryo won’t survive the pregnancy, or won’t survive after its born
What is genetic counselling?
constructing family history of heritable genetic disorders to determine risk of genetic defects and chromosomal abnormalities
- have the opportunity to make a decision if they want to proceed with having the biological child, or use another method
What is prenatal diagnosis?
testing done after a women is pregnant, to assess for genetic defects and chromosomal abnormalities
When is CVS or amniocentesis conducted? (2)
- when genetic counselling determines there’s a risk for genetic abnormalities
- when mother is over age 35 (high risk of birth defect)
What is prenatal treatment?
therapies administered prenatally to reduce effects of genetic abnormalities
- done when we know that there’s a genetic disorder in the child
- drugs, medication, surgery can be used as treatment
What does behavioural genetics study? (4)
- examines how genes and experience combine to influence human traits, abilities, and behaviours
- studies of families (twins, adoption)
- examines how the genetic and environmental influences compare
- compare people who have varying degrees of relatedness (ie. similar environment but dissimilar DNA, comparison between identical and fraternal twins, regular siblings with adoptive siblings)
What is range of reaction?
wide range of potential expressions of genetic trait, depending on environmental opportunities and constraints
ie. severe lack of nutrition can alter person’s growth even though they have certain traits and genes that suggest otherwise
What is canalization?
heredity narrows range of development to only one or a few outcomes
ie. humans are biologically programmed to start walking at around 12 months regardless of minor influences, however, if there is some level of severe deprivation the child experiences, they might not start walking until later
What are gene-environment correlations?
many traits are supported by both genes and environment
ie. parent has a genetic musical ability and they pass it on to their child, then they raise the child in a musical environment
What are passive gene-environment correlations?
child doesn’t do anything, but parent provides gene and environment
What are active gene-environment correlations?
niche-picking:
child actively seeks out activities and experiences in their environments that are supportive of their genetic tendencies
When is the embryonic period?
3rd–8th week after conception
What happens during the embryonic period?
most rapid growth in prenatal development: all organs are functioning
What happens if defects occur during the embryonic period?
result in miscarriage or abortion (because organs are not functioning)
When is the fetal period?
9th week to birth
What is the age of viability?
age at which the fetus can survive outside the womb
today, this age is 22 weeks (4 months early)
How many pounds is considered low birth weight?
< 5.5 lbs
How many pounds is considered very low birth weight?
< 3.5 lbs
How many pounds is considered extremely low birth weight?
< 1 lb
What are the 2 types of low birth weight babies?
preterm
small for date
What are preterm babies?
born before due date, usually with low birth weight
What are small for date babies?
baby weighs less than what it should even though it is a full-term (born on due date) baby
What is the leading cause of infant mortality in the world?
low weight births
What are low weight babies overwhelmed by?
stimulation (noise, light, touch)
- it is difficult to parent these babies
What is Kangaroo care?
parents hold the baby on their bare chest (skin-to-skin contact) and turn the baby’s head/ear to their chest so they can hear the parent’s heartbeat
What are the benefits of Kangaroo care?
babies who receive this care (compared to low weight babies who don’t) sleep more, cry less, gain weight faster, leave the hospital earlier
What are teratogens?
agents that causes damage to prenatal development, such as disease, drug, or other environmental factors, producing a birth defect
Teratogens
What are critical periods?
periods when embryo/fetus is more susceptible to damage from exposure to teratogens
Teratogens
When are teratogens not as critical, but can still do damage?
8th month of pregnancy
Teratogens
What are the 3 factors that can affect the effect of teratogens?
- critical periods
- dose (amount of exposure influences effects of teratogens)
- individual differences (individual variation in susceptibility to teratogens)
Teratogens
What are the 7 types of teratogens?
- prescription and nonprescription drugs (thalidomide)
- alcohol
- cigarettes
- marijuana
- Cocaine and Heroin
- maternal illness
- environmental hazards
Teratogens
What is thalidomide?
was used to treat morning sickness, but it caused truncated limbs, blindness, deaf, ½ of the babies died
Teratogens
What is Fetal Alcohol Spectrum Disorder?
continuum of effects of exposure to alcohol, which vary with the timing and amount of exposure
Teratogens
How does alcohol affect pregnancy?
- drinking during embryonic period is much more critical (critical period)
- leading cause of developmental disabilities: growth deficiencies, motor deficits, language and cognitive difficulties
- more severe exposure = more problems in school (cognitive)
Teratogens
How do cigarettes affect pregnancy?
linked with
- fetal death
- premature birth
- low birth weight, heart defects
- respiratory disorders
- Sudden Infant Death Syndrome (SIDS)
Teratogens
How does marijuana affect pregnancy?
- low birth weight, shorter length babies
- needs more research for definitive answers (difficult to do because marijuana was illegal)
Teratogens
How does cocaine and heroin affect pregnancy?
- babies are born addicted, and go through withdrawal once they are born
- low birth weight
- impaired motor performance
- issues with brain development
Teratogens
What happens if mothers get Rubella (German measles) during pregnancy?
if mother gets it during the first 10 weeks of pregnancy, it is related to major birth defects, blindness, heart defect, brain damage
if mother gets it later in pregnancy, the risks are less severe
Teratogens
What environmental hazards affect pregnancy?
exposure to chemicals, radiation, air pollution, heavy metals
Maternal Characteristics
How does age affect pregnancy?
older = can be more problematic
- pregnancy over 35 is strongly related to miscarriages, stillbirths, increase risk of Down Syndrome
Maternal Characteristics
How does nutrition affect pregnancy?
- poor mothers lack adequate access to proper nutrition, which can lead to complications in pregnancy, birth process, and baby
- mothers should consume 2000-3000 calories a day to sustain pregnancy
Maternal Characteristics
Mothers who are poor r live in non-industrialized countries likely don’t receive Vitamin B9 (folic acid). What is Vitamin B9 deficiency linked with?
linked with spina bifida (failure of neural tube)
Maternal Characteristics
Where do mothers get Vitamin B9?
inside prenatal vitamins
Maternal Characteristics
How do mothers’ emotional well-being affect pregnancy?
mothers exposed to chronic and severe stress during pregnancy, it poses risk to the fetus
Maternal Characteristics
How do highly stressed mothers affect pregnancy?
more likely to low birth weight, premature, and require longer hospital stay after being born
- when stressed, stress hormones cross over the placenta which raises fetal heart rate and activity level, which is problematic for the fetus
Maternal Characteristics
How does high-level stress in mothers affect children?
can produce long-term effects on children
child will later on exhibit symptoms of anxiety, ADHD, and aggression in childhood, adolescence, and adulthood
Maternal Characteristics
What is prenatal care?
basic set of services provided to improve pregnancy outcomes
- nutritional advice
- prenatal vitamins
- regular check-ups with doctor
Maternal Characteristics
Describe the ethnic and socioeconomic disparities of prenatal care.
- ethnic groups are less likely to seek early prenatal care because minorities are more likely to be low socioeconomic groups
- lack of transportation to get to the doctor
- job has limited opportunities to leave work in the middle of the day to go to a doctor’s appointment
Maternal Characteristics
Why might a woman not seek prenatal care?
- many do not have health insurance, and less likely to seek out prenatal care
- when a woman is pregnant, but not sure they want to be, they will not seek prenatal care because then they are acknowledging the pregnancy
- women with negative experiences in health care system are less likely to voluntary to put themselves in the system
