Embryo to Fetus Flashcards

Question

INTRAUTERINE GROWTH RETARDATION

Answer 1

PLACENTAL FACTORS: 1. REDUCED BLOOD FLOW - HYPOTENSION, RENAL DISEASE, KNOT IN CORD 2. DYSFUNCTION - NOT NORMAL PLACENTA, SMALL, BRUISED, UNDER DEVELOPED, RETARDS GROWTH 3. MULTIPLE PREGNANCY GENETIC: 1. SMALL MOTHERS HAVE SMALL BABIES 2. SMALL BABIES RUN IN SOME FAMILIES 3. CHROMOSOMAL ABERRATIONS - DOWN’S SYNDROME, TRISOMY 18 ENVIRONMENTAL: 1. MALNUTRITION - FAMINES, POOR DIET 2. CIGARETTE SMOKING - FETAL TOBACCO SYNDROME 3. DRUGS - LSD, HEROINE, MORPHINE, AMPHETAMINES, ETOH SMALL BABIES WHETHER PREMATURE OR SFD ARE MORE VULNERABLE AND LESS LIKELY TO SURVIVE!! Placental factors: underdeveloped, twins/triplets, bruised, knots in cord Genetic factors: small women--\>small babies Environmental factors: smoking--\>small babies (active or passive smoking), alcohol is toxic to neural crest cells. recreational drugs, etc.

Answer 2

Fetal surgeries have been done for more 20 year – but dangerous May be used to treat spina bifida or diaphragmatic hernias (improperly formed diaphragm-guts in thoracic cavity...fatal condition normally) But risky for both mother and fetus Because this is very dangerous- is only done in rare case For example – has been used to treat diaphragmatic hernia, but dangerous and may not be very effective Also may be used to treat spina bifida but again controversial Best use is when fetal surgery accompanies delivery. E.g. fetus has tumor in thorax that will prevent breathing remove tumor using fetal surgery just before delivery, then baby can breath when born Called exit surgery. Likely fetal surgery will become obsolete Replaced by stem cell and gene therapy. E.g. stem cells could be used to treat sickle cell anemia.

Answer 3

New branch of medicine Recognizes that what we are as adults and our adult health can be linked to the conditions we were exposed to in utero Recognized only recently Intensively researched during last 10 years Heart disease – early onset associated with birth weight – smaller babies tend to have increased risk for heart disease Obesity – If mothers are obese during pregnancy, their children will tend to be obese. If mothers fat is surgical removed to restore normal weight- he subsequent children are more likely to also have normal weight Diabetes – diabetic mother – has high glucose- this disrupts fetal metabolism- predisposes her children to type II diabetes Air- cord blood is loaded with the air pollutants a mother breathes. New borns have PAH (polycyclic aromatic hydrocarbons) in blood. Evidence they have already affected DNA even before birth Stress- If mothers are stressed during pregnancy – they are more likely to have anxious children and children with schizophrenia What happens in utero affects the rest of life. some adult diseases originate in utero Barker Theory-makes conditions come on sooner than they otherwise would. IF metabolism is set slower in utero, it stays slow the rest of life--\>tendency towards obesity

Answer 4

Reduced fetal growth is strongly associated with a number of chronic conditions later in life. These chronic conditions include coronary heart disease, stroke, diabetes, and hypertension. Also called Thrifty phenotype. This increased susceptibility results from adaptations made by the fetus in an environment limited in its supply of nutrients. Like between fetal birth weight and later early onset of adult disease first made by David Barker 20 years ago Poorest areas in England and Wales had highest rates of heart disease. Found birth weights lower in poorer regions. Strong correlation between birth weight and later heart disease. Not taken seriously at first but now many studies have been done confirming his observations. Why- if resources are limited in utero, fetus may not be able to develop all organs fully, may also put resources in to brain at expense of the heart and other organs. Later in life, the deficiencies may take their toll.

Answer 5

The DOHaD hypothesis states that exposure to an unfavorable environment during development (either in utero or in the early postnatal period) programs changes in fetal or neonatal development such that the individual is then at greater risk of developing adulthood disease. Flip side of this hypothesis Exposure to a good environment in utero will favor development of a healthy adult Could be very important in public health – an improvement of quality of life Pregnant women may make simple adjustments during pregnancies and help their fetus develop in a way that helps them remain healthy longer in adulthood.

Answer 6

The answer may lie in epigenetics = Study of gene activity that do not involve changes in the genetic code but still get passed down to successive generations. Patterns of gene expression governed by the epigenome- which marks genes telling them if they should turn off or on Or if they should be highly or lowly expressed.

Answer 7

Involves mitotically and meiotically inheritable changes in gene expression that do not involve a change in the DNA sequence itself. ## Footnote Often accomplished by methylating select regions of DNA (as we saw in genomic imprinting)

Answer 8

1. SWITCH SPECIFIC GENES ON OR OFF A gene regulatory protein attaches to a specific sequence of DNA on one or more genes. Once there, it acts like a switch, activating genes or shutting them down. 2. RECRUIT ENZYMES THAT ADD AND REMOVE EPIGENETIC TAGS Gene regulatory proteins also recruit enzymes that add or remove epigenetic tags. Enzymes add epigenetic tags to the DNA, the histones, or both. Epigenetic tags give the cell a way to "remember" long-term what its genes should be doing.

Answer 9

methylation can turn off a gene regulatory protein-temporary; methylation-permanent what you eat can affect the methylation of DNA. gene expression is then affected.

Answer 10

As cells grow and divide, cellular machinery faithfully copies epigenetic tags along with the DNA. This is especially important during embryonic development, as past experiences inform future choices. A cell must first "know" that it is an eye cell before it can decide whether to become part of the lens or the cornea. The epigenome allows cells to remember their past experiences long after the signals fade away.

Answer 11

folic acid, betaine, choline, B vitamins can all methylate DNA

Answer 12

Agouti=brown

Answer 13

So if a pregnant mother's diet can affect the child's epigenetic outcome, can dad's diet do the same? Quite possibly, according to scientists who delved into the well-kept, historical records of annual harvests from a small Swedish community. These records showed that food availability between the ages of nine and twelve for the paternal grandfather affected the lifespan of his grandchildren. But not in the way you might think. ## Footnote Food abundance for the grandfather was associated with a reduced lifespan for his grandchildren. Shortage of food for the grandfather was associated with extended lifespan of his grandchildren. Food abundance, on the other hand, was associated with a greatly shortened lifespan of the grandchildren. Early death was the result of either diabetes or heart disease. Could it be that during this critical period of development for the grandfather, epigenetic mechanisms are "capturing" nutritional information about the environment to pass on to the next generation?