Prenatal Development

fertilization of a zygote

Genetics + Heredity Review

→ chromosome (each gamete = 22 autosomes + 1 sex chrom.), gene, allele (homo/heterozygous; dom/rec), genotype, phenotype, meiosis, mitosis, zygote (fertilized egg), IVF, incomplete dominance (pink flowers), codominance (red + white speckled flower), DNA (and when it replicates), pleiotropy (gene affect more than 1 phenotypic trait)

→ behavioral genetics (polygenic inheritance, psy. traits inheritance, twin/adoption studies)

→ interactionism (in dev. psy, how genes + environment interacts)


Brain Development Review

→ neuron, axon, dendrite, synapse, myelination, synaptogenesis, synaptic pruning (synapses = eliminated)


Conception + Pregnancy

twins

  • monozygotic (identical)

    • formed from 1 zygote that split into 2 (can have 2 different placentas*)

  • dizygotic (fraternal)

    • formed from different zygotes → different genomes

*developed by fetus’ genetic material → allows for communication w/ mother

timeline

  • conception (2 weeks) - germinal period

  • 3-8 weeks - embryonic period

  • 9-38 weeks - fetal period


pregnancy sickness

  • an adaptation that protects fetus from toxins in the diet

  • occurs during the 1st trimester (fetus’ nervous system = vulnerable)

  • women who experience pregnancy sickness → less likely to miscarriage


Environmental Influences

teratogen - external agent that can harm a developing embryo/fetus

  • has a sensitive period (1st trimester) where it’s highly susceptible to enviro. influences

  • maternal diseases

    • rubella (can lead to congenital rubella syndrome), STDs/STIs

  • drugs

    • thalidomide: non-prescription drug meant to alleviate nausea & morning sickness → caused severe birth defects

    • prescription medications

    • aspirin, ibuprofen, caffeine

    • alcohol → fetal alcohol spectrum disorder (FASD)

      • physically - microencephaly, malformations of heart/limb/joints/face/vision/hearing

      • brain & CNS - poor memory/coordination/balance etc.

      • behavioral - hyperactive, low social skills

    • smoking (nicotine & CO)

      • increases risk for cleft lip/palate

    • marijuana → functional changes of amygdala

      • leads to tremors, sleep disturbances, lack of interest

    • radiation, chemical & pollutants


!! lack of folic acid → spina bifida (neural tube defect where spinal column & membrane fail to close during pregnancy)