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child development chapter three
Terms in this set (53)
when does prenatal development begin and end?
begins with fertilization, ends with birth (38-40 weeks)
how long does prenatal development usually last?
what are the three periods of prenatal development?
1. germinal- organism is a zygote (conception to 2 weeks)
2. embryonic- organism is an embryo (3rd-8th week)
3. fetal- organism is a fetus (9th week- birth)
when does the germinal period begin?
begins with conception, process called fertilization
what is fertilization?
when the sperm and egg unite in one of the two fallopian tubes
what is the zygote
fertilizd egg, has a full complement of human genetic material
what does the zygote do after fertilization?
after fertilization in fallopian tube, it moves towards the uterus (can take up to a week)
what are the sex differences in conception, for miscarriage, though the life span?
120-150 males conceived per 100 females
however, males miscarried at a higher rate than females, they are more vulnerable to developmental disorders, and are more vulnerable to illness throughout the life span
describe the germination period
a period of rapid cell division
what is the blastocyst? what does the inner layer eventually become?
4th day after conception.
inner mass: cells eventually become the embryo
what is the trophoblast and what does it later provide?
outer layer of the blastocyst, provides nutrition and support for the embryo
what is implantation? about when does it take place?
the attachment of the zygote to the uterine wall (11-15 days after conception)
what weeks are the embryonic period? describe this period
3rd-8th week. rate of cell differentiation intensifies. major development occurs following implantation
what is an embryo?
when blastocyst attaches to the uterine wall, the mass of cells is now called an embryo. 3 layers of cells form
what are the 3 layers of cells of an embryo? what will they become?
everyone eventually develops from these 3 layers
1. endoderm- inner layer, will develop into the internal body parts (digestive and respiratory systems)
2. mesoderm-middle layer, will develop into parts that surround the internal areas (circulatory system, bones ,muscles, reproductive system, excretory system)
3. ectoderm- outermost layer, will develop into surface parts (nervous system, hair, sensory receptors)
what are the two patterns of development?
1. cephalocaudal development (head to body) - areas near head develop faster
2. proximal distal development 0 development starts in center areas, proceeds to more distal areas
what is the amnion? umbilical chord? placenta?
*amnion- bag or envelope containing a clear fluid in which the developing embryo floats
*umbilical chord- tube that contains the blood vessels that travel from the placenta to the developing organism and back again
*placenta- permits exchange of materials between he bloodstream of the fetus and that of the mother (semipermeable, very small molecules can pass through)
what is organogenesis?
the process of organ formation during the firs two months of prenatal development. organs are especially vulnerable to environmental changes while they are being formed
what are 2 important developmental milestones of the embryonic phase?
3rd week- development of the neural tube
4th week- heart beat
what is the neural tube? what does it eventually become?
forms out of the ectoderm at 3rd week.
u-shaped groove, eventually becomes the brain and spinal chord
describe the fetal period
9th week to birth
fetus is about an inch long at the start of the fetal period
how big is the average north american baby at birth?
average baby is 20 inches long and weighs 7.5 lbs
what are 5 important developmental milestones of the embryonic period? at what weeks do they occur?
9th week- all internal organs present
12th week- sex is distinguishable
18th-20th week- can begin to feel baby move and doc can hear heart beat
24th-25th week- baby is biable, brain and lungs sufficiently developed so if born at this time, has a chance of surviving
32nd week- prenatal learning, responds to sounds, CNS developed enough so that learning and memory can occur
how are the periods of prenatal development associated with trimesters?
first trimester- zygote, embryo, fetus
2nd trimester- fetus
3rd trimester- fetus
what were the results of The Cat in The Hat study? what does this demonstrate?
babies can recognize things they heard while in womb, want to hear mothers voice and familiar story
what are : a tarragon, teratology, behavioral teratology?
teratogen- any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes
teratology- the field of study that investigates the causes of birth defects
behavioral teratology- field of study that investigates teratogens that do not cause physical birth defects but can alter the developing brain and influence cognitive and behavioral functioning
what are the effects of teratogens?
physical birth defects
alter the developing brain
some effects not apparent until later in life
what are 4 general principles concerning effects of teratogens?
1. genetic susceptibility- effects impacted by genotype of woman and of the fetus or embryo
2. nature of teratogen
3 close-response relation- longer exposure/higher dose = more harm
4. timing of exposure- do more damage when they occur at some points in development than others
can teratogens influence development before conception? for men and women?
Concerning exposure to teratogens during prenatal development: during which prenatal period is the developing organisms usually not susceptible to teratogens, and if they do have an effect, the effect is more likely miscarriage?
usually not susceptible in first two weeks, effect is most likely a miscarriage (if there is one)
embryonic period- probability of a structural deficit is greatest
fetal period- more likely to stunt growth or create problems in the way the organs function
During which prenatal period is the probability of a structural defect the greatest?
During which prenatal period is the effect more likely to be to stunt growth or create problems in the way organs function?
what are the 3 stages of labor? which is the shortest? the longest?
1. regular uterine contractions
2. infant descends through birth canal and is delivered
3. uterus expels the placenta
what is the function of contractions?
to open the cervix, longest of the stages
what begins and what ends at the second stage of labor?
baby's head moves through cervix, ends with complete emergence
what happens during the third stage of labor?
placenta, umbilical chord expelled and detached
what is a breech position?
baby's butt is first to emerge during delivery, can cause respiratory problems
what is a c-section?
baby is removed from uterus via an incision in the mothers abdomen
what is the perinatal environment
the environment surrounding birth (huge variability within and across cultures)
what are the 3 basic kinds of medications used for labor? what are they used for?
1. analgesia- used to relieve pain
2. anesthesia- blocks sensation and consciousness (epidural block numbs woman from waist down)
3. oxytocin/pitocin- synthetic hormone used to stimulate contractions
what is natural childbirth? what is prepared childbirth?
tries to reduce mothers pain through education and breathing methods/relaxation techniques
prepared- includes a special breathing technique t control pushing in the final stages of labor
What are some ways the social environment of birth varies across historical periods and across cultures?
99% of births in US occur in hospitals
what are midwives?
what are doulas?
provides continuous, physical, emotional, and educational support for the mother before, during, and after childbirth
functions as part of birthing team
what is an apgar score? why is it done and when?
done at 1 min and 5 min after birth
evaluates infants heart rate, respiratory effort, muscle tone, body color, and reflex irritability
scored 0, 1, or 2. total score is 0-10
what are the five health signs that are rated and scored?
appearance (skin color)
activity (of muscles)
what is the neonatal behavioral assessment scale (NBAS)? why is it done and when? what does it assess?
done 24-36 hours after birth
measures neurological development, 16 reflexes, and reaction to people and objects. used to assess normal, healthy , full term infants
what is kangaroo care?
keep baby on chest
what is the neonatial intensive care unit network neurobehavioral scale (NNNS)? what does it assess?
assesses newborn's behavior, neurological and stress responses. used to assess at risk infants
how long does the postpartum period last? what adjustments are needed?
about 6 weeks
what are some physical adjustments that take place during the postpartum period?
dramatic changes in hormone production, loss of sleep, fatigue
what are postpartum blues and postpartum depression?
~70% feel postpartum blues- feel dressed, anxiety, upset, usually goes away after 1-2 weeks
~10% feel postpartum depression- major depressive episode, usually about 4 weeks after delivery
what age is the adjustment to a new baby most difficult for siblings?
2-4 years old