Midterm 2 Flashcards
What are epigenetics?
The study of changes in gene expression that are meditates by the environment
How did the Dutch Hunger Winter affect the children who were born to mother who were pregnant with them during this period? How did the time of the pregnancy affect the outcome?
- the Dutch hunger winter caused families to be malnourished thus a reduction in caloric intake for pregnant women.
- Metabolic restriction in early pregnancy permanently alters the child’s metabolism.
- Mothers near the end of pregnancy: their babies were well fed in the beginning, then had a loss in caloric intake so the babies were birthed small and stayed small for their lives.
- Mothers that experienced the hunger winter in the beginning of their pregnancies were malnourished during the first trimester:
- however, then they were well-fed during the rest so babies were born at a normal weight.
- BUT as they aged, there were higher rated of obesity, diabetes, and heart disease.
What is associated with smaller stature as adults?
Malnourishment in the last trimester
What can malnourishment in the first trimester lead to?
- elevated risk of obesity, heart disease, and diabetes
- presumably because the fetal cells adapted to limited nuitrients which would have immediate benefits but led to long term issues
Explain Meaney et at.’s studies on maternal behavior in rat pups.
What does poor mothering have? What can we learn from the cross fostering component of this study?
- The study looks at the changes in gene expression in rates with inadequate maternal care (attentive vs inattentive mothers)
- Inattentive mothers have stressed offspring.
- Their genes were highly methylated, & DNA that is methylated will not actively transcribe
- Rats born to attentive mothers then raised by an inattentive foster mom, had genes that were highly methylated which goes to show that the first week of life is critical
Oberlander observed epigenetic changes in the fetal cord blood that were linked to maternal depression & anxiety in the 3rd trimester. What were these changes? How did this relate to stress-induced cortisol levels in 3 month olds?
- Greater maternal depression and anxiety during the 3rd trimester was associated with increased DNA methylation within the glucocorticoid receptor gene measured in fetal cord blood
- this measure of DNA methylation was related to increased infant cortisol response to stress at three months
Oberlander chart
Prenatal exposure = maternal depression & anxiety during the 3rd trimester,
Epigenetic effect = increased DNA methylation within the NR3C1 gene promoter in fetal cord blood,
Outcome = increased stress-induced cortisol levels in 3 month old infants
Prenatal stress poses risks for the child’s outcomes. What are some of the concerning outcomes?
- epigenetic changes in the fetus
- epigenetic changes in structures of the mother’s body that support fetal development (placenta)
- epigenetic changes in the mother that may affect infant caregiving
What did researchers find when they studies monozygotic twins as part of a longitudinal study at the Spanish Cancer Center?
- Twins born from a single egg (monozygotic)
- pattern of DNA methylation was highly similar in infant pairs
- differences in DNA methylation increased with age
Blastocyst
a ball of cells that forms early in pregnancy, about five to six days after sperm fertilizes the egg
Amniotic Fluid
- protects the fetus from infection
- cushions the fetus’ movements and helps it move
- regulates fetal body temperature
- helps the fetus’s digestive and respiratory systems develop
Source of Amniotic Fluid
- initial source: amniotic cells
- 2nd trimester: fetal urine is the main contributor - other contributors: diffusion across membranes; fetal respiration
Period of the embryo
the period extends from the time the organism becomes attached to the uterus to the 8th week of pregnancy.
Period of the fetus
begins in the 9th week after conception, with the first signs of the hardening of the bones, and continues until birth
Placenta
- provides nutrients and oxygen to your baby through the umbilical cord
Umbilical cord
- one vein that carries food and oxygen from the placenta to the fetus
- two arteries that carry waste from the fetus back to the placenta
- the umbilical cord is filled with a substance called Wharton’s jelly that cushions and protects these blood vessels
Cephalocaudal development
Areas near the head develop before areas further down on the body
Proximodistal development
center outward - structures near the torso develop more rapidly than those in the periphery
Age of Viability
- the age at which a baby can survive with medical assistance in the event of premature birth
- between 22 and 26 weeks
What are the protective functions of the amniotic fluid?
- protects the fetus from infection
- cushions the fetus movement and helps it move
- regulates fetal body temp
- protects from maternal falls or sudden blows
- helps the fetus’s digestive and respiratory systems develop
How do the placenta and umbilical cord function to promote fetal development?
Placenta:
- The placenta connects to the umbilical cord through thousands of microscopic “fingers” of tissue (chorionic villi) containing a network of blood vessels that connect to the fetus’ circulatory system.
When the mother’s blood comes in contact with the villi, nutrients are exchanged for waste through the villi walls. The villi also act as a partial filter, preventing some viruses and bacteria from reaching the fetus.
Umbilical Cord
- One vein that carries food and oxygen from the placenta to the fetus
- Two arteries that carry waste from the fetus back to the placenta
- The umbilical cord is filled with a substance called Wharton’s jelly that cushions and protects these blood vessels
When does clef lip and cleft palate emerge in development? When are they usually repaired?
- the cleft lip develops 4-7 weeks.
- the palate (roof of the mouth) develops 5-9 weeks.
- a cleft lip may be repaired at 3-6 months of age.
- a cleft palate tends to be repaired at 9-12 months of age (so it doesn’t interfere with language development)
What are some of the things the fetus does in the womb? Do these actions aid development?
- embryo makes spontaneous movements at about 5-6 weeks after conception, bending its head and spine then movements become more complex
- weeks later it will move even more and the movements will become smoother and more coordinated
- swallowing movement begins at 11 weeks
- sucking movements begin at 15 weeks
- fetal breathing begins at about 10 weeks
Is there any reason to think that early experience shapes taste preferences? Explain the evidence.
Yes, mennella et al. (2001) - mothers drank carrot juice for 3 weeks near the end of their pregnancy
- Babies whose moms had carrot juice preferred the carrot-flavored cereal further the same was seen with breastfeeding
Does the fetus have a sense of touch? Do they respond to light? Voices?
- yes, the fetus touches its body, the umbilical cord, and sucks its thumbs
- at 26 weeks old, the fetus heart rate and movement increase if a bright light is held against the mother’s abdomen
- change in heart rate and changes in movement when there is sound
What voices preferences might we see in newborns?
- Fetus responds to both male and female voices but there are differences in how the infant responds to the voice of its mother versus a female stranger
- prefers the language that they were exposed to in utero (native language)
Describe the “Dr. Seuss” book reading study
- Tested: when just 2.5 days-old
- Testing procedure: baby sucked in one pattern on the pacifier they would hear the familiar story if they sucked in a different pattern they would hear the unfamiliar story
- Finding: infants sucked in the pattern that would allow them to hear the familiar story - even when both stories were read by another woman
What was the difference between the two supplements (Atole and Fresco) used in the Guatemala food supplementation study? Were outcomes different for the two supplements? Explain.
- Fresco is a sugary drink
- Atole is gruel (mixture of vegetable and protein mixture) that was combined with skin milk and sugar
- Found that caloric intake increased the same amount in both villages bc more drinks (Fresco) was consumed than gruel (Atole)
- this increased calorie improved outcomes
- those women who increased their calorie intake over the pregnancy by atleast 20,000 calories cut their risk of delivering a low-birth weight baby in half
How did providing iron-folic acid supplements to anemic women in Nepal improve child outcomes?
The children who received iron-folic acid supplements were tested at 7-9 years of age and they tested higher on working memory, inhibitory control and fine motor function
