Chapter 2 biological beginnings Flashcards
Why might an extended childhood period have evolved?
because humans require time to develop a large brain and learn the complexity of human societies
What is the swiss army knife theory?
Theory that, like a swiss army knife, the human mind is like a number of independent domains or tools
What are chromosomes?
threadlike structures made up of DNA
“Many of our evolved psychological mechanisms are domain-specific”
What does this mean?
the mechanisms apply only to a specific aspect of a person’s psychological makeup
What is genetic expression? What is it affected by?
Genetic expression is the activity of genes. Both events outside and inside of the cell can promote or inhibit it, like stress, exercise, radiation
What are some common genetic principles that determine how a genotype is expressed to create a particular phenotype?
- dominant and recessive genes
- sex-linked genes
- polygenetic inheritance (like height- it’s influenced by many genes)
What are some common chromosome abnormalities?
- Down syndrome (extra chromosome 21)
- Klinefleter Syndrome (XXY)
- Jacob’s Syndrome (XYY)
- Turner syndrome (XO)
What are some common gene-linked mutations?
PKU- metabolic disorder, can cause mental retardation
Sickle-cell anemia- disorder that limits the body’s oxygen supply
What are the 3 periods of pregnancy?
- the germinal period
- the embryonic period
- the fetal period
How long does the germinal period last?
the first two weeks after conception
What happens during the germinal period?
The zygote is formed, undergoes rapid cell division, and becomes a blastocyst (or a hollow ball of cells that eventually becomes the embryo)
When does the embryonic period occur?
from 2-8 weeks after conception
What are the 3 layers of cells that an embryo forms?
- endoderm- inner layer, develops into digestive and respitory systems
- mesoderm- middle layer, develops into circulatory system, bones, muscles, excretory system and reproductive system
- ectoderm- outermost layer, develops into nervous system, sensory receptors, and skin parts
What happens during the embryonic period?
The clump of cells is now an embryo, 3 layers of cells that will eventually become every part of the body forms. Major structures like the brain, spinal cord, and heart start to form.
When does the fetal period occur?
Two months to conception
What happens during the first trimester?
The germinal and embryonic periods; the beginning of the fetal period
at 12 weeks (fetal period), it can move arms and legs, fingerprints are present, and sex is distinguishable
What happens during the second trimester?
Fetal period;
rapid growth, movement can be felt, vision and hearing develop
What happens during the third trimester?
fetal period;
lungs maturing, antibodies being transmitted, move to “head down” posision
How long does each trimester last?
1st- conception- 12 weeks
2nd- 16- 24 weeks
3rd- 28- birth
What are the 4 phases of brain develpment that occur during the prenatal period?
- formation of the neural tube
- neurogenisis
- neural migration
- neural connectivity
What are some prenatal tests?
ultrasound, fetal MRI, chorionic villus sampling, amniocentesis
What is a teratogen?
any agent that can potentially cause a birth defect
What are some parental factors that can harm the embryo or fetus?
- maternal weight and diet
- maternal age
- maternal drug use
- maternal stress
- paternal exposure to lead, radiation, pesticides, and petrochemicals
What are the 3 stages of birth?
- Dialation of cervix
- Pushing and birth of baby
- Delivery of placenta
What is the apgar scale?
a scale widely used to assess the health of a newborn 1 and 5 minutes after birth
evaluates heart rate, respitory effort, muscle tone, body color, and reflex irritability
What is involution?
the process by which the uterus returns to its prepregnant size 5 or 6 weeks after birth
