Chapter 2 Flashcards
zygote
the new cell formed by the process of fertilization
genes
the basic unit of genetic information
DNA (deoxyribonucleic acid) molecules
the substance that genes are composed of that determines the nature of every cell in the body and how it will function
chromosomes
rod-shaped portions of DNA that are organized in 23 pairs
monozygotic twins
twins who are genetically identical
dizygotic twins
twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time
dominant trait
the one trait that is expressed when two competing traits are present
recessive trait
a trait within an organism that is present, but not expressed
genotype
the underlying combination of genetic material present (but not outwardly visible) in an organism
phenotype
an observable trait; the trait that is actually seen
homozygous
inheriting from parents similar genes for a given trait
heterozygous
inheriting from parents different forms of a gene fir a given trait
polygenic inheritance
inheritance in which a combination of multiple gene pairs is responsible for the production of a particular trait
X-linked chromosome
genes that are considered recessive and located only on the X chromosome
behavioral genetics
the study of the effects of hereditary on behavior
Down syndrome
a disorder produced by the presence of an extra chromosome of the 21st pair; once referred to as mongolism
fragile X syndrome
a disorder produced by injury to a gene on the X chromosome, producing mild to moderate mental retardation
sickle-cell anemia
a blood disorder that gets its name from the shape of the red blood cells in those who have it
Tay-Sachs disease
a disorder that produces blindness and muscle degeneration prior to death; there is no treatment
Klinefelter’s syndrome
a disorder resulting from the presence of an extra X chromosome that produces underdeveloped genitals, extreme height, and enlarged breasts
genetic counseling
the discipline that focuses on helping people deal with issues relating to inherited disorders
ultrasound sonography
a process in which high-frequency sound waves scan the mother’s womb to produce an image of the unborn baby, whose size and shape can than be assessed
chorionic villus sampling (CVS)
a test used to find genetic defects that involves taking samples of hairlike material that surrounds the embryo
amniocentesis
the process of identifying genetic defects by examining a small sample of fetal cells drawn by a needle inserted into the amniotic fluid surrounding the unborn fetus
temperament
patterns of arousal and emotionality that represent consistent and enduring characteristics in an individual
multifactorial transmission
the determination of traits by a combination of both genetic and environmental factors in which a genotype provides a range within which a phenotype may be expressed
fertilization
the process by which a sperm and an ovum - the male and female gametes, respectively - join to form a single new cell
germinal stage
the first - and shortest - stage of the prenatal period, which takes place during the first 2 weeks following conception
placenta
a conduit between the mother and fetus, providing nourishment and oxygen via the umbilical cord
embryonic stage
the period from 2 to 8 weeks following fertilization during which significant growth occurs in the major organs and body systems
fetal stage
the stage that begins at about 8 weeks after conception and continues until birth
fetus
a developing child, from 8 weeks after conception until born
infertility
the inability to conceive after 12 to 18 months of trying to become pregnant
artificial insemination
a process of fertilization in which a man’s sperm are placed directly into a woman’s vagina by a physician
in vitro fertilization (IVF)
a procedure in which a woman’s ova are removed from her ovaries, and man’s sperm are used to fertilize the ova in a laboratory
teratogen
an environmental agent such as a drug, chemical, virus, or other factor that produces a birth defect
preterm infants
infants who are born prior to 38 weeks after conception
low-birthweight infants
infants who weigh less than 2,500 grams (around 5 1/2 lbs) at birth
small-for-gestational-age infants
infants who, because of delayed fetal growth, weigh 90% (or less) of the average weight of infants of the same gestational age
very-low-birthweight infants
infants who weigh less than 1,250 grams (around 2.25 lbs) or, regardless of weight, have been in the womb less than 30 weeks
postmature infants
infants still unborn 2 weeks after the mother’s due date
Cesarean delivery
a birth in which the baby is surgical removed from the uterus, rather than traveling through the birth canal
fetal monitor
a device that measures the baby’s heartbeat during delivery
stillbirth
the delivery of a child who is not alive, occurring in less than 1 delivery in 100
infant mortality
death within the first year of life
mitosis
accounts for replication of most types of cells
meiosis
process when gametes - sperm and ova - are formed the adult human body
reaction range
the potential degree of variablilty in the actual expression of a trait due to environmental conditions
spontaneous mutation
when genes for no known reason sponataneously change their form
karyotype
a chart containing enlarged photos of each of the chromosomes
first- trimester screen
combines a blood test and ultasound sonography in the 11th to 13th week of pregnancy and can identify chromosomal abnormalities and other disorders
neuroticism
the degree of emotional stability an individual characteristically displays
extroversion
degree to which a person seeks to be with others, to behave in an outgoing manner and generally to be sociable
blastocyst
fertilized egg
ectoderm
outer layer of the embryo, will form skin, hair, teeth, sense organs, brain and spinal cord
endoderm
inner layer of the embryo, produces digestive system, liver pancreas, and respiratory system
mesoderm
middle layer of embryo, forms muscles, bones, blood, and circulatory system
corticotropin-releasing hormone (CRH)
released about 266 days after conception, and releases various hormones to triggers labor
oxytocin
released by pituitary gland, causes contractions
episiotomy
an incision sometimes made to increase the size of the opening of the vagina to allow the baby to pass
Lamaze birthing techniques
using breathing techniques and relaxaton training, to prevent tensing up while in labor
Bradley method
“husband coached childbirth” – principle that childbirth should be as natural as possible to involve no medication or medical interventions
Hypnobirthing
self-hypnosis during delivery that produces a sense of peace and calm, thereby reducing pain
