Chapter 2: Foundations of Human Development

Created by ethansawyer 

Upgrade to
remove ads

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

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set