PSYC 336 - Ch 3

By the fifth month, some of the ______ are added

"finishing touches": toenails, fingernails, eyelids covered by hair called lanugo and white cheesy substance called vernix that protects fetus from damage due to movements

About _____% of zygotes fail in what they call _________.

30%, miscarriage (embryonic period)

About ____% of preterm births have no identifiable cause

50

The fetus can hear and see around

6 months

When do genetically male and female embryos have primitive versions

6 weeks

Only ________ percent of birth defects are thought to be primarily caused by environmental factors, and from ________ of birth defects have no known cause based on the present state of knowledge

7%-10%, 50-60%

Identical (monozygotic) twins

twins formed from the division of a single zygote into two genetically identical organisms

Common birth practices

1. Birthing in hospital 2. Midwife 3. Doula 4. Childbirth classes (Lamaze: natural process and uses a variety of techniques to reduce the perception of pain and Bradley method: reduce or eliminate the use of medications to relieve pain during childbirth and uses the partner as a coach) 5. Labor coach 6. Epidural: pain medication injected in mother's spine to block sensation from waist down, but may block desire to push 7. C-section: baby is removed by doctor by cutting open stomach (can be in distressful situations or when mom wants to, people want to reduce rate)

Four general principles governing the impact of teratogens on prenatal development

1. Dose 2. Genes 3. Cumulative effects 4. Timing of exposure

Scientists divide prenatal development into three stages or periods

1. Germinal period: prenatal development in the first two weeks after fertilization 2. Embryonic period: development from the third through the eighth week 3. Fetal period: prenatal development from the ninth week until birth

Four main processes of brain development

1. Neurogenesis 2. Neural migration 3. Neural differentiation 4. Formation of neural connections

Three subgroups of FASD

1. classic fetal alcohol syndrome: facial deformities and mental disabilities (mothers drank five or more drinks twice a week during first trimester) 2. only some of the facial and cognitive symptoms 3. cognitive impairments but no physical defects

Common birth complications include

Preterm birth: birth before the 37th week of pregnancy Low birth weight: a term used to describe babies born weighing less than 5½ pounds (2,500 grams) Respiratory distress syndrome: a condition in which preterm infants' lungs do not produce enough surfactin, leading to respiratory problems Small-for-date: an infant who weighs less than the normal range for a given gestational age, may have been exposed to teratogenic conditions, more likely to have respiratory distress syndrome

Dose (teratogens)

Teratogens generally have more negative effects if they are present in higher concentrations or over a longer period of time ex) the more alcohol per week a pregnant mother consumes, the lower the child's intelligence quotient (IQ) score several years after birth

Development programming

changes to the physiology of the fetus from environmental stimuli during sensitive periods of prenatal development that result in long-term changes in health A leading explanation for effects of undernutrition, an adaptive mechanism in times of scarcity

Stage 2 of birth (delivery/expulsion)

uterine contractions and the efforts of the mother combine to push the baby, head first, through the birth canal Once the baby is breathing, the umbilical cord is cut, and the short remaining stalk is sterilized. It will fall off within a week or so to reveal the belly button.

Sexual differentiation provides a good example of ________

bidirectional interactions between genes and sex hormones produced by the fetus's genital region, dynamic system (self-organizing of chaos)

The top of the neural tube will be the ______ and the bottom will be the ______

brain, spinal cord

Surrogate

can receive an embryo from the couple through in vitro fertilization or be artificially inseminated with the father's or a donor's sperm

Formation of neural connections

carrying out neural role by connecting through synapses

Neural tube defect + 2 conditions at each area

defects resulting from failure of the neural tube to close 1. Anencephaly: embryo fails to develop a brain above the level of the brainstem 2. Spina Bifida: failures of neural tube to close in the middle or lower regions, various motor, bladder, and cognitive difficulties

Neurons that fail to make useful connections with other neurons

degenerate quickly

Neural migration

neurons will start in neural tube (very center of brain) and migrate outwards and form layers of brain (like an onion growing) In subcortical regions of the brain, older neurons move simply because they are pushed outward from the center of the neural tube into place by the production of new neurons

What happened in the Nurse-Family Partnership experiment?

nurses visit the home of low-income and teenage mothers several times during the pregnancy and once a month for the first two years of the child's life mothers in this program had fewer premature births, fewer subsequent pregnancies, better work and relationship circumstances, and lower rates of child maltreatment than an untreated control group

researchers found that adults who had been exposed to the famine as embryos and fetuses during the first trimester had increased rates of

obesity, coronary heart disease, and glucose intolerance due to diminished insulin secretion

Implantation (Germinal Period)

the process by which the blastocyst becomes attached to the uterus (about only 30% gets implanted)

Gestation period begins around

24 weeks

The neural tube typically closes on day ___ after fertalization

25

What is linked to drinking alcohol during pregnancy?

Fetal Alcohol Spectrum Disorder, lowered IQ, problems in behavior, attention, memory, and school performance, reduced brain size

Common techniques for monitoring health of fetus

Most common: measurements of the weight gain of the mother Ultrasound: measure the size and gestational age of the fetus, determine whether growth is in the normal range, and detect multiple fetuses, developmental defects First Trimester Screen: ultrasound and maternal blood test to identify risk for chromosomal normality Triple screen test: a blood test given to the mother than can identify abnormal levels of three compounds (AFP, hCG, Estriol) originating in the fetus or placenta that are indicators of possible fetal abnormalities (neural tube, for example) Amniocentesis: conducted between the 15th and 18th weeks of the pregnancy and has only a 0.5 percent risk of early termination of the pregnancy

Also at 24 weeks, many connections (synapses) between neurons exist because of which two phases

Phase 1: genes tell neurons where to go and they form many connections (genetic <-> neural in Gottlieb's developmental systems model) Phase 2: connections that are used are kept, others are pruned out (environment <-> neural in Gottlieb's model)

Genes (teratogens)

Response to teratogens depends in part on the fetus's genetic vulnerability to a particular agent. ex) smoking can contribute to symptoms of ADHD in children with a particular genotype (gene-environment interaction)

In genetically male fetuses, the ____ gene "turns on" and in females, the _____ protein turns on to take away the other structure

SRY, COUP- TFII

Cumulative effects (teratogens)

The effects of teratogens appear to be greater when they are present in combination. ex) cocaine abuse is often associated with using other drugs such as alcohol and with poor nutrition. This makes it difficult to isolate the effects of cocaine use

_______ is the origin of the entire nervous system

The neural plate

How does the development of the neural tube illustrate the bidirectional interactions that occur at every level of Gottlieb's developmental systems model?

The neural tube develops because of an intricate dialogue between genes that turn on and off and biological signals from tissues that result from the action of the genes (Wallingford et al., 2013). Outside environmental influences, in the form of insufficient folic acid, can alter the gene-brain tissue interactions in ways that lead to permanent alteration of the spinal cord or brain.

Timing of exposure (teratogens)

The timing of exposure can be crucial, as illustrated by the thalidomide tragedy. ex) retinoic acid (marketed as Accutane), used for the oral treatment of severe acne in teenagers and adults. It is harmful even at low doses, and the critical period for exposure is from the third to fifth week of the embryonic period

Stage 1 of birth (cervical dilation and effacement)

Uterine contractions also cause effacement of the cervix (thinning) The contractions of the uterus in stage 1 also push the baby's head downward so that it presses against the cervix (2-3 min apart) Final part is transition

Low levels of AFP and abnormal levels of hCG and estriol have been associated with

a chromosome abnormality such as Down syndrome Not diagnostic but indicative

In the last two months, the fetus adds ______, and this is the period when _______

a few inches in length but gains 4 pounds in weight fat tissues essential for temperature regulation outside the womb develop

males who overate in the years just before puberty tended to have sons and grandsons with

a higher risk of diabetes, cardiovascular disease, and early death due to alterations of epigenetic chemicals that regulate the expression of genes on the Y chromosome

Apgar scale

a rating system of the physical condition of a newborn infant that assigns scores of 0-2 for five criteria: skin color, heart rate, responsiveness to stimuli, muscle tone, and respiration "Appearance, Pulse, Grimace, Activity, and Respiration" Babies receive a score of 0 to 2 on the five criteria If the five-minute Apgar score is 7 or higher, this is considered healthy. If it is lower than 7, a neonatologist will be called to the delivery room to further assess and possibly intervene with the baby. Normal healthy newborns typically obtain scores of 8 to 9.

Birth defect

a structural abnormality in the brain or body that is present at birth

Neurons are the _____________ and begin production in the _________ through ________

basic information-processing cells of the brain, fifth week, neurogenesis

Infertility is defined as

absence of pregnancy after 12 months of unprotected sexual intercourse with the same partner

Teratogens

an environmental agent that disrupts the normal process of prenatal development

Neurogenesis

creation of neurons by cell division, uses glial cells for nutrients and removal of waste (prenatal period - 20th week)

What have studies found about prepared childbirth vs standard medical practice in US?

does not produce healthier mothers and babies

A possible reason that mutations occur more often in sperm cells than in egg cells is that

eggs are produced only once (during the female's fetal period), whereas sperm cells must be regenerated about twice a month (more room for error)

Some of the effects of smoking may be due to modifications of the

embryo's epigenetic profile, which fits over the DNA strand and controls whether particular genes are turned on or off at various points in development smoke decreases methylation

Brazelton Neonatal Behavioral Assessment Scale

evaluates infants' reflexes, ability to respond to people, control of their own behavior, and attention to objects and other stimuli. identifying infants who need medical attention and in alerting parents to the needs of their child by going through the test with them ex) the examiner places a cloth over the baby's face to test whether the baby attempts to remove it or turn away from it as a reflexive protection of the airways

The Cat in the Hat experiment shows that capacities to recognize are in place

far before birth (fetal period)

In vitro fertilization

fertilization "in glass," meaning in a petri dish, then transferred back into uterus more prenatal complications

On top of avoiding substances, doctors recommend to

focus on gaining an appropriate amount of weight during pregnancy, engaging in moderate intensity exercise that does not jostle the uterus, taking recommended amounts of vitamins and minerals, and consulting a health care professional regularly to discuss ongoing medications as well as checkups on the health of mother and fetus

The embryo undergoes what major changes in the first two weeks of the embryonic period

formation of neural tube development of primitive cardiovascular system

Synapses

gaps between neurons that allow them to communicate with each other chemically

complete androgen insensitivity vs congenital adrenal hyperplasia

genetic males develop female external genitalia, genetic females develop more masculine external genitalia

After fertilization, the ______ begins. The ______ travels down the fallopian tubes and toward the uterus. After a day, it divides continually via _______. Four days after, the zygote has become a ball of cells with a hollow core, called the ________. A cluster of cells inside the blastocyst develops into the ________. The outer cells form the ___________ that sustain the embryo. The blastocyst then implants itself into the ______ by ___ weeks

germinal period, zygote, mitosis, blastocyst, embryo, supporting structures, uterine wall, 2 weeks

FASD is more likely to occur in women who

have other risk factors, particularly if they live under conditions of extreme poverty or stress

During the embryonic period, the _________ develops separate chambers, and the _____ and ________ begin to produce red blood cells. The ________ and ________ grow but are not ready to function yet. The ____ begins to form as two sets of structures that fuse in the middle toward the end of the second month.

heart, liver, spleen, stomach, intenstines, face

Neural differentiaton

neurons initially are all alike but are genetically programmed to have specific destination, and once they go there they begin differentiating migrating neurons can become any type of neuron

The risk is greater the ________ the gestational age and birth weight of the newborn

lower

The ______ are the last organ system to develop

lungs

By 3 months, what begins to form?

major features of face arms and legs grown brain begins to connect with muscles

What is linked to smoking during pregnancy?

miscarriage, premature birth, and low birth weight, Sudden Infant Death Syndrome, asthma, cancer, obesity, type 2 diabetes, and coronary heart disease, doubles the risk that the child will become addicted to tobacco if that child starts smoking, nicotine reduces the ability of the placenta to supply oxygen and nutrients to the fetus

Over long-term, small for date infants have which effects?

more likely to have respiratory distress syndrome, they have more difficulties in school, more social and behavioral problems, and lower intelligence test scores

The difficulty of measuring the effects of specific drug abuse in pregnancy is that

mothers with a substance use disorder are likely to use or abuse multiple substances, including alcohol, whose effects can be quite similar to marijuana

The essentialness of the fetus to move around shows that _______ and ______ influence each other bidirectionally

movement, growth of physical structures

What percentage of babies are born in the hospital?

over 99%

During labor, levels of the hormone _________ are important in maintaining regular contractions of the uterus

oxytocin, a hormone that initiates uterine contractions and stimulates other hormones, such as estrogen, that regulate uterine contractions

Kangaroo care

practices involving skin-to-skin contact between infant and parent for an extended period every day, used for when neonatal intensive care units create unnatural conditions that isolate preterm babies from parents recommended for full-term infants and their parents and is increasingly popular in the United States because it simulates conditions in the womb

Glial cells

support and nourish neurons, remove waste products provide guide wire for neuron when migrating

The addition of a mild sedative called thalidomide did what effectively

stopped the development of arms and legs of babies

The greatest health risks for preterm babies involve

systems of the body that are undergoing final development in the last three months of the pregnancy, including the lungs, immune system, and digestive system.

Preterm birth is more common among

teenage mothers or mothers over 35, low-income women, African American women (even adjusting for income levels), and women who have had a prior preterm birth Other risk factors include carrying more than one baby (such as twins or triplets), a maternal infection, maternal high blood pressure, stress, inadequate prenatal care, and use of a variety of substances, including tobacco, alcohol, and street drugs (CDC, 2013e)

One important risk factor for neural tube defects is a lack of

the B-complex vitamin folic acid in the mother's diet

Stage 3 of birth (placental separation)

the contractions of the uterus push the placenta, other fetal membranes, and the remainder of the umbilical cord out

One reason the heart develops so early is that

the fast-growing embryo is in great need of nutrition and oxygen (embryonic period)

Behaviors in the womb like yawning, blinking, kicking, and swallowing signify that

the fetal brain is coordinating fetus's actions and responses to stimuli

Why are older fathers more likely to have offspring with schizophrenia, autism, and reduced IQ or social functioning?

the number of de novo mutations (those that are present in the child but not the parent) in the child went up with the age of the father but not the mother, occur during the process of gamete formation or fertilization and hence are unexpected based on the DNA of the parents

At first, males and females have _______ organs

the same

Mothers can pass diseases or the effects of diseases to their babies in two ways

through the placenta and during the birth process

Three subgroups of FASD show that the principles of ______ and ______ are applicable

timing of exposure, dose

Why do, beginning in the prenatal period and continuing after birth, about 50% percent of all of the neurons in development undergo this kind of programmed death?

to set up an efficient information-processing system in the brain

Fraternal (dizygotic) twins

twins formed from the fertilization of two separate ova by two separate sperm cells no more similar than two regular siblings, more common in older age (30s)

The placenta can stop bacterial diseases but not

viruses ex) rubella (German measles, a virus that can cause multiple prenatal deficits like deafness, cataracts, and heart, urinary, intestinal, bone defects, intellectual impairment when the mother contracts it during the first trimester ex) HIV, and about 25 percent of infected children develop AIDS symptoms, can take AZT to reduce risk

Infertility is more common and steep with

women