How can we help?

You can also find more resources in our Help Center.

58 terms

Chapter 2: Foundations of Human Development

STUDY
PLAY
chromosomes
threadlike structures in the nuclei of cells that contain genetic material
autosomes
first 22 pairs of chromosomes
sex chromosomes
23rd pair of chromosomes; these determine the sex of the child
deoxyribonucleic acid (DNA)
molecule composed of four nucleotide base that is the biochemical basis of heredity
gene
group of nucleotide bases that provide a specific set of biochemical instructions
genotype
person's hereditary makeup
phenotype
physical, behavioral and psychological features that result from the interaction between one's genes and the environment
alleles
variations on genes
homozygous
when the chromosomes in a pair are the same
heterozygous
when the alleles differ from each other
dominant
form of an allele whose chemical instructions are followed
recessive
allele whose instructions are ignored when it is combined with a dominant allele
incomplete dominance
situation in which one allele does not dominate another completely
sickle-cell trait
disorder in which individuals show signs of mild anemia when they are deprived of oxygen; occurs in individuals who have one dominant allele for normal blood cells and one recessive sickle-cell allele
phenylketonuria (PKU)
inherited disorder in which the infant lacks a liver enzyme
Huntington's disease
progressive and fatal type of dementia
behavioral genetics
the branch of genetics that studies the inheritance of behavioral and psychological traits
polygenic inheritance
when phenotypes are the result of the combined activity of many separate genes
monozygotic twins
result when a single fertilized egg splits to form two new individuals; also called identical twins
dizygotic twins
result of the fertilization of two separate eggs by two sperm; also called fraternal twins
reaction range
a genotype manifested in reaction to the environment where development takes place, so a single genotype can lead to a range of phenotypes
niche-picking
process of deliberately seeking environments that are compatible with one's genetic makeup
nonshared environmental influences
forces within a family that make siblings different from one another
prenatal development
the many changes that turn a fertilized egg into a newborn human
in vitro fertilization
process by which sperm and an egg are mixed in a petri dish to create a zygote, which is then placed in a woman's uterus
eugenics
effort to improve the human species by letting only people whose characteristics are valued by a society mate and pass along their genes
zygote
fertilized egg
implantation
step in which the zygote burrows into the uterine wall and establishes connections with a woman's blood vessels
germ disc
small cluster of cells near the center of the zygote that will eventually develop into a baby
placenta
structure through which nutrients and wastes are exchanged between the mother and the developing child
embryo
term given to the zygote once it is completely embedded in the uterine wall
ectoderm
outer layer of the embryo that will become the hair, outer layer of skin, and the nervous system
mesoderm
middle layer of the embryo; becomes the muscles, bones, and circulatory system
amnion
inner sac in which the developing child rests
amniotic fluid
fluid that surrounds the fetus
umbilical cord
structure containing veins and arteries that connects the developing child to the placenta
period of the fetus
longest period of prenatal development, extending from the 9th until the 38th week after conception
cerebral cortex
wrinkled surface of the brain that regulates many functions that are distinctly human
vernix
substance that protects the fetus' skin during development
age of viability
age at which a fetus can survive because most of its bodily systems function adequately; typically at 7 months after conception
spina bifida
disorder in which the embryo's neural tube does not close properly
stress
physical and psychological responses to threatening or challenging conditions
teratogen
agent that causes abnormal prenatal development
fetal alcohol syndrome (FAS)
disorder affecting babies whose mothers consumed large amounts of alcohol while they were pregnant
fetal alcohol spectrum disorder (FASD)
group of conditions that include fetal alcohol syndrome
ultrasound
prenatal diagnostic technique that bounces sound waves off the fetus to generate an image of the fetus
amniocentesis
prenatal diagnostic technique that involves withdrawing a ample of amniotic fluid through the abdomen using a syringe
chorionic villus sampling
prenatal diagnostic technique that involves taking a sample of tissue from the chorion
fetal medicine
field of medicine concerned with treating prenatal problems before birth
crowning
appearance of the top of the baby's head during labor
doula
a person familiar with child birth who is not part of the hospital medical staff but instead provides emotional and physical support throughout labor and delivery
hypoxia
a birth complication in which umbilical blood flow is disrupted and the infant does not receive adequate oxygen
caesarean section (C-section)
surgical removal of infant from the uterus through an incision made in the mother's abdomen
preterm (premature)
babies born before the 36th week after conception
low birth weight
weight of less than 2,500 grams (5 pounds) in a newborn
very low birth weight
weight of less than 1500 grams (3 pounds) in a newborn
extremely low birth weight
newborns who weigh less than 1000 grams (2 pounds)
infant mortality
the number of infants out of 1000 births who die before their first birthday