Chapter 2: Prenatal Development and Newborns

Question 1

Gamete

Answer 1

Sex cell (egg or sperm) with 23 chromosomes

Question 2

Zygote

Answer 2

Combinations of both gametes, 46 chromosomes, grows via mitosis (cell division)

Question 3

Day 4 of fetal development

Answer 3

The inner cell mass of the zygote is arranged into a hollow sphere (where identical twins split from)

Question 4

End of week 1 of fetal development

Answer 4

The zygote has implanted into the uterine lining; differentiation begins

Question 5

Week 2 of pregnancy

Answer 5

Inner cell mass of the zygote differentiates into three layers

Question 6

After zygote has implanted into the uterine lining:

Answer 6

The neural tube is created, which eventually becomes the brain and spinal cord

Question 7

Epigenesis

Answer 7

Aristotelian belief that the parts of the human body develop in succession

Question 8

Cell migration

Answer 8

Movement of newly formed cells to a new location in the body/growing embryo

Question 9

Cell differentiation

Answer 9

Embryonic stem cells specialize to become different cell types (underlying process unknown)

Question 10

Apoptosis

Answer 10

Programmed cell death

Question 11

Cephalocaudal Development

Answer 11

The areas of the fetus closer to the head form faster than those far from the head

Question 12

Embryo at 4 weeks

Answer 12

Four folds in front head develops, primitive heart forms and pumps blood, arm and leg buds emerge

Question 13

Embryo at 5.5 - 8.5 weeks

Answer 13

Nose, mouth, and palate differentiate (where cleft palate can form)

Question 14

Fetus at 9 weeks

Answer 14

Rapid brain growth, all internal organs present, sexual differentiation occurs, eyes and ears forming, fingers and toes present

Question 15

Fetus at 11 weeks

Answer 15

Heart develops to basic structure, spine and ribs are visible, major divisions of the brain form

Question 16

Fetus at 16 weeks

Answer 16

Lower body growth accelerates, external genitals developed, fetal movement increases (primitive breathing motion)

Question 17

Fetus at 18 weeks

Answer 17

Fine hair and greasy coating covers the body, facial expressions and sucking reflex can be observed

Question 18

Fetus at 20 weeks

Answer 18

Oriented to head-down position, massive weight gain period

Question 19

Fetus at 28 weeks

Answer 19

Triple in weight, brain and lungs fully developed, has reached the point of viability. Increased eye movement and neural activity. Auditory systems are developed and functioning

Question 20

Placenta

Answer 20

Semipermeable defensive barrier for the fetus, provides hormones (progesterone and estrogen) and nutrients; can affect the baby and the mother

Question 21

Hemochorial placenta

Answer 21

Inside the uterus; rewires the endometrium to reroute bloodflow to the baby, paralyzes the mothers arteries. Considered an ‘invasive’ placenta, which is comprised of fetal cells (that can become part of the mother’s organs forever)

Question 22

Rates of miscarriage

Answer 22

1/3 pregnancies miscarry. 2/3 of that 33% occur before the pregnancy is even detectable. 25-50% of women experience a miscarriage. 6-15% of clinically recognized pregnancies end in miscarriage.

Question 23

Non-genetic effects on prenatal development

Answer 23

Mother’s emotions, teratogens, mother’s health

Question 24

O’Connor et. al. study

Answer 24

2002; Studied affects of maternal stress during pregnancy on behavior at 4 years old. Found a relationship between high stress levels and high behavioral issues. Many confounds (mental health, time gap, genetic predisposition to stress, socio-economic status, etc.)

Question 25

DiPietro et. al. study

Answer 25

2002; measured fetal behavior as a response to maternal stress. More stress associated with a more active fetus, which relates to more behavioral issues at 4 years old. Directional issue with this relationship

Question 26

Teratogen

Answer 26

materials that affect a fetus. Caffeine, alcohol, cigarettes, illegal drugs, etc. Unethical to study; not causal

Question 27

Fetal Alcohol Spectrum Disorder (FASD)

Answer 27

Related to maternal alcoholism. Impaired cognition, facial deformity, and other problems arise. Baby cannot metabolize the alcohol in the mother’s bloodstream

Question 28

Critical period for teratogens

Answer 28

Each developmental process has a critical period that can be affected by teratogens. Duration and time of exposure can lead to different affects on the fetus.

Question 29

Fetal behaviors in utero

Answer 29

Movement begins between 5-6 weeks, then slows with growth due to lack of room and increased sleep time

Question 30

Vestibular system development

Answer 30

Begins around 5 months, fully develops at birth

Question 31

Visual system development

Answer 31

Begins at 26 weeks, fully develops after birth with visual stimuli. Babies are born nearsighted. Can be measured by reading heartrate change when exposed to light in utero

Question 32

Auditory system development

Answer 32

Develops by the end of the second trimester. Babies’ uterine environment is very loud, but they show a preference to hearing their mother’s voice

Question 33

Taste/smell development

Answer 33

Amniotic fluid can have a taste/smell based on mother’s diet, and can lead to preferences before/directly after birth

Question 34

Habituation approach to studying fetal learning

Answer 34

Watch for changes in signals after a baby has habituated to a certain stimulus. Amplitude of sucking, preferential looking/head-turn, and heart rate measurements.

Question 35

Salk heartbeat experiment

Answer 35

1973; 3 groups of babies, one heard normal heartbeat, one heard fast heartbeat, and control heard no heartbeat. Fast group babies got upset, slow/normal group babies gained more weight and cried less than the control group

Question 36

DeCasper and Spense experiment

Answer 36

1986; studying fetal learning to sounds. Pregnant mothers read a story to their fetuses. When the babies were born, their sucking amplitude was measured when exposed to the familiar story and the novel story. Found infants preferred the familiar story.

Question 37

Six stages of newborn arousal

Answer 37

Quiet sleep (8 hrs), active sleep (8 hrs), drowsing (1 hr), alert awake (2.5 hs), active awake (2.5 hrs), crying (2 hrs)

Question 38

Newborn sleep

Answer 38

Babies sleep around 16 hours a day, twice as much as adults. They spend 50% of their sleep time in REM sleep, and their sleep state switches more dramatically

Question 39

Infant crying

Answer 39

Cry for 2 hours a day. Crying peaks at 6 weeks old, then decreases to 1 hour a day during the first year. Begins as random, becomes more communicative with age.

Question 40

Colic

Answer 40

Unknown reason for extreme increase in crying in infants. Usually ends around 3 months of age.

Question 41

Low birth weight

Answer 41

Premature babies are born before 35 weeks gestation. Have a weight of less that 5.5 pounds. Can be caused by malnutrition, teratogens, or being a multiple (twin or triplet)

Question 42

Effects of low birth weight

Answer 42

Immature organ development, problems thermoregulating. Higher risk of child abuse in the long term.

Question 43

Apgar test

Answer 43

Easy way to asses the health of a newborn directly after birth. Common practice in western hospitals.

Question 44

Multi-risk models

Answer 44

Risk factors tend to occur together. The more risk factors compound on an infant, the more likely their development will be affected

Question 45

Fetal learning

Answer 45

Fetuses habituate to stimuli in utero. They can learn general sounds and rhythms, but not specific content about language, music, etc.