Chapter 2: Prenatal Development and the Newborn Period

Q: Pregnancy is ___ weeks long and starts ___ weeks earlier with the start of menstruation.

A: Pregnancy is 40 weeks long, starts 2 weeks earlier with start of menstruation.

Q: What is conception?

A: Conception is the union of sperm (male gamete) and ovum (female gamete).

Q: What is a gamete?

A: A gamete is a reproductive cell containing half the genetic material of the donor.

Q: After conception, what genetic material is present?

A: After conception have all the genetic material needed to build a new organism.

Q: What explains why babies aren't just clones of their parents?

A: The fact that gametes contain half the genetic material of the donor explains why babies aren't just clones of their parents.

Q: What is a zygote?

A: A zygote is a fertilized egg cell; starting point for development of the organism.

Q: How soon does the zygote begin dividing?

A: The cell begins dividing exponentially within 12 hours of fertilization, doubling roughly twice a day.

Q: By the 4th day after conception, what happens to the zygote (and its subsequent cell stages)?

A: By 4th day after conception, become arranged into a hollow sphere with an inner cell mass.

Q: What happens if the ball of cells becomes successfully implanted in the uterine lining before the end of the second week?

A: The inner cell mass becomes the embryo, and the other cells become the support system.

Q: What is the amniotic sac?

A: The amniotic sac is a fluid filled membrane that surrounds and protects the developing organism.

Q: What is the placenta?

A: The placenta is a temporary support organ with semipermeable membrane allowing exchange of materials between mother and fetus.

Q: How are the fetus and placenta connected?

A: The fetus and placenta are connected via the umbilical cord.

Q: What is transferred from parent to fetus?

A: Oxygen, nutrients, minerals, and some antibodies.

Q: What is transferred from fetus to parent?

A: Waste products (carbon dioxide, urea).

Q: What are monozygotic (identical) twins?

A: Monozygotic (aka identical) twins — monozygotic = "one zygote".

Q: What are dizygotic (fraternal) twins?

A: Dizygotic (aka fraternal) twins — dizygotic = "two zygote".

Q: What determines whether monozygotic twins share a placenta and/or amniotic sac?

Q: What do the four developmental processes do?

A: Four developmental processes transform a zygote to embryo to fetus.

Q: What is mitosis?

A: Mitosis – cell division.

Q: What is cell migration?

A: Cell migration.

Q: What is cell differentiation?

A: Cell differentiation – embryonic stem cells.

Q: What is apoptosis?

A: Apoptosis – "cell death".

Q: Where is the role of apoptosis seen in fetal development?

A: The role of apoptosis is seen in the development of the hand.

Q: How does apoptosis contribute to the development of fingers?

A: Requires the death of cells in between the ridges of the hand plate for the fingers to separate.

Q: What is an embryo?

A: Developing organism from the 3rd to 8th week.

Q: What begins to develop during the embryonic stage?

A: Major systems and internal organs begin (but don't complete) their development – heart, limbs, sensory organs, brain.

Q: What is cephalocaudal development?

A: Organs/structures near the head start to develop earlier than those farther from the head ("head to tail development").

Q: When does the neural tube begin to develop into the brain and spinal cord?

A: In the 4th week.

Q: How does the neural groove fuse during neural tube development?

A: The neural groove fuses together first at the centre and then outward in both directions as if two zippers were being closed.

Q: After the neural tube closes, what will the top of the neural tube develop into?

A: The top of the neural tube will develop into the brain.

Q: What is a fetus?

A: Developing organism from the 9th week until birth.

Q: What happens at 9 weeks of fetal development?

A: All major organs present.

Q: What happens at 16 weeks of fetal development?

A: Development of lower half; external genitals (may be) visible.

Q: What happens at 28 weeks of fetal development?

A: Lungs and heart sufficiently developed that in cases of premature birth, possible the fetus could survive without medical intervention.

Q: What fetal movements are associated with later self-regulation skills?

A: Moving, wiggling, and kicking.

Q: What might thumb sucking, hiccupping, and burping in the fetus be practicing?

A: Practicing eating?

Q: Why does the fetus swallow fluid?

A: Promotes digestive system and palatal development.

Q: When does fetal movement start and how does it change leading up to birth?

A: Movement starts at approx. 6 weeks; leading up to birth, spends most time resting (like a newborn does).

Q: How does the fetus experience tactile stimulation?

A: As a result of its own activity.

Q: What are examples of fetal tactile contact with its own body?

A: Grasping umbilical cord, rubbing face, sucking thumb.

Q: What sensory apparatus is functioning before birth and what does it provide information about?

A: Sensory apparatus in the inner ear that provides information about movement and balance.

Q: How developed is fetal vision before birth?

A: Minimal.

Q: What visual preferences does the fetus show?

A: Predispositions to look toward facelike stimuli.

Q: Can the fetus taste before birth?

A: Yes – can detect and discriminate flavours in amniotic fluid.

Q: What does the fetus show regarding flavours before birth?

A: Flavour preferences before birth.

Q: What were the three groups in Mennella et al. (2001)?

A: CW (carrot during pregnancy, water after pregnancy), WC (water during pregnancy, carrot after pregnancy), WW (water during and after pregnancy).

Q: What was observed with negative faces in Mennella et al. (2001)?

A: Showed negative faces when they had carrot.

Q: What did mothers perceive about their babies in Mennella et al. (2001)?

A: Perceived their babies enjoyed the carrot flavour.

Q: How did prenatal exposure to carrot influence intake?

A: Those who had carrot during pregnancy were influenced more to the carrot flavour.

Q: What does Mennella et al. (2001) suggest about prenatal learning?

A: What is learned prenatally influences preferences after birth!

Q: How can the fetus "smell" later in prenatal development?

A: By inhaling amniotic fluid through the nose.

Q: How does amniotic fluid acquire odour?

A: Amniotic fluid takes on odour from what pregnant parent eats.

Q: How is sound experienced by the fetus and why is it important?

A: Sound is prevalent feature of fetal environment, may stimulate brain development.

Q: What specific sounds does the fetus hear?

A: Pregnant parent's voice, speech versus music.

Q: What did pregnant parents do in the prenatal hearing study?

A: Read The Cat in the Hat aloud in the last 6 weeks of their pregnancy.

Q: How were newborns tested for recognition of the story?

A: Newborns were fitted with a special pacifier-headset device; the pattern in which the babies sucked on the pacifier determined what book was read (Cat in the Hat vs. another children's book).

Q: What was the result of the prenatal hearing study?

A: Babies tended to suck in the pattern that enabled them to hear the familiar story.

Q: What is habituation?

A: Simple form of learning that involves a decrease in response to repeated or continued stimulation; seen at 30 weeks gestation in visual and auditory stimuli.

Q: What is dishabituation?

A: Introduction of a new stimulus rekindles interest following habituation to a repeated stimulus.

Q: What is a teratogen?

A: Potentially harmful external agent that can cause damage during prenatal development.

Q: What factors influence the impact of teratogens?

A: Individual differences in genetic susceptibility.

Q: What type of impact can teratogens have?

A: Cumulative impact.

Q: What is fetal programming in the context of teratogens?

A: Fetal programming.

Q: What is the sleeper effect in prenatal development?

A: Sleeper effect.

Q: What does the effect of a teratogen depend on?

A: When the teratogen was encountered during prenatal development.

Q: What is a sensitive period?

A: Time during which a developing organism is most sensitive to the effects of external factors.

Q: Do different systems have the same sensitive periods?

A: Different systems = different periods.

Q: How does exposure level relate to outcomes for teratogens?

A: Usually follows a dose-response relationship – greater exposure = worse outcomes.

Q: Are teratogens the only hazards to prenatal development?

A: No – other maternal factors (age, nutrition, mental health) also play an important role.

Q: What is the leading cause of fetal brain injury?

A: Alcohol.

Q: How is alcohol during pregnancy generally considered in terms of preventability?

A: Generally considered to be the most preventable cause.

Q: What disorders or effects are associated with prenatal alcohol exposure?

A: Associated with fetal alcohol spectrum disorder (FASD) and associated ill effects.

Q: What is prenatal marijuana exposure associated with?

A: Learning and memory problems and more, but difficult to study because use often co-occurs with other teratogens exposure.

Q: How can tobacco affect prenatal development?

A: Through cigarette smoking, secondhand smoke, and/or e-cigarettes.

Q: How does nicotine affect the parent and fetus?

A: Nicotine decreases oxygen levels for parent and fetus.

Q: What outcomes are associated with prenatal tobacco exposure?

A: Associated with low birthweight, higher risk of SIDS, cancer, ADHD, lower IQ.

Q: What is the risk of Accutane (acne medication) to prenatal development?

A: Extreme risk to prenatal development.

Q: What precautions do recipients of Accutane often take?

A: Recipients often use multiple forms of birth control and regular pregnancy testing.

Q: What are the effects of antidepressants during pregnancy for the parent?

A: Typically, positive (even life saving) effects for parent.

Q: What is known about the effect of antidepressants on prenatal development?

A: Inconclusive evidence on effect on prenatal development.

Q: What was Thalidomide used for in the 1960s?

A: Drug to prevent nausea.

Q: What was initially thought about Thalidomide and the placenta?

A: Thought to not cross the placenta.

Q: What effects did Thalidomide have on babies?

A: Some babies born with major limb deformities.

Q: When were the serious effects of Thalidomide present?

A: Serious effects only present when drug was taken in weeks 4-6 after conception (sensitive period effects).

Q: How do different forms of environmental pollution act on prenatal development?

A: Different forms of pollution act in combination.

Q: What are some examples of pollutants affecting prenatal development?

A: Toxic metals, synthetic hormones, plastic ingredients, pesticides, herbicides.

Q: How can air and water pollution impact prenatal development?

A: Air and water pollution – e.g., Grassy Narrows and White Dog First Nation: dumping of mercury by nearby mill children and continued contamination.

Q: What are sources of lead exposure relevant to prenatal development?

A: Lead (pipes, paint [especially old paint], historic lead in gasoline).

Q: What is a future direction of research on environmental pollutants?

A: Nanoplastics.

Q: At approximately how many weeks of conception does birth typically occur?

A: ~38 weeks of conception.

Q: Are fetuses aged 35-41 weeks unusual or unsafe?

A: Fetuses aged 35-41 weeks are not unusual and generally safe.

Q: What starts labour?

A: We're not totally sure! Fetus and placenta likely play a role; proteins secreted by fetal lungs are a suspect.

Q: What happens once labour begins?

A: Cascade of hormones – e.g., oxytocin causes contractions of uterine muscles.

Q: How is synthetic oxytocin used in labour?

A: Synthetic oxytocin used to induce labour contractions.

Q: What is the ideal fetal position for birth?

A: Ideally fetus is head-down.

Q: What percentage of fetuses are breech and what does this mean?

A: 3-4% of fetuses are 'breech' -> increased risks for parent and fetus.

Q: What causes pain for the parent during birth?

A: Muscle contractions and stretching = pain.