Exam 4 Flashcards
(233 cards)
In what weeks of fetal development do congenital abnormalities most often occur?
1) Week 1-5
2) Weeks 4-7
3) Weeks 10-15
2) Weeks 1-3
2) Weeks 4-7
Within fetal circulation, what is the main structure that provides gas exchange?
1) Umbilical vein
2) Umbilical artery
3) Placenta
4) Foramen ovale
3) Placenta
What structure carries oxygen rich blood and nutrients to the fetus? Where does it branch into?
- The umbilical vein
- It branches into the liver or to the ductus venosus
What structure allows passage of blood to divert from the umbilical vein past the liver? Where does the blood mix into?
- The ductus venosus allows oxygen rich blood to divert past the liver
- The blood mixes into the inferior vena cava
The foramen ovale allows blood to move from the ____ ____ to the ____ ____
right atrium -> left atrium
The foramen ovale helps perfuse which fetal structure?
The brain
Why does blood move from the right to left atrium via the foramen ovale? Why is this helpful?
- It moves from the right to left atrium because pulmonary pressures are very high due to hypoxic vasoconstriction creating high right ventricle pressure and high right atrium pressures, higher than the left side of the heart.
- It is helpful because more oxygen rich blood shunts to the left side of the heart to be sent for systemic circulation instead of pulmonary
Why does hypoxic vasoconstriction occur in developing fetuses?
Because they are not breathing at this point (there’s no gas exchange to oxygenate the blood), so the body vasoconstricts the pulmonary arteries and capillaries to shunt blood to oxygen rich areas.
What structure accepts blood from the pulmonary arteries and moves it to the aorta? Why does this occur?
- The ductus ateriosus
- Blood moves through the ductus ateriosus for the same reason it moves through the foramen ovale, high pressure in the pulmonary circuit
What structures does the ductus ateriosus perfuse?
The lower limbs
What does the umbilical artery do and why does it carry blood to this location in utero? How many are there?
- It carries oxygen poor blood back to the placenta because the placenta has low resistance/pressure
- There are two umbilical arteries
What are two major changes in circulation when a fetus becomes a newborn that cause subsequent changes in circulation?
1) There is no more placenta (causes decreased prostaglandins)
2) The lungs take in oxygen
What causes Wharton’s Jelly to contract? What does this contraction cause?
- Temperature drop causes Wharton’s Jelly to contract around umbilical arteries/veins
- It causes blood flow to stop at this point creating high resistance at this point and cutting off blood flow to the umbilica vein/arteries, and ductus venosus
What causes hypoxic vasoconstriction to be released in newborns? What does this cause?
- The first breaths of the newborn allowing oxygen to enter the lungs and perfuse the capillaries releasing the hypoxic vasoconstriction
- This causes a drop in the pulmonary circuit resistance/pressure
What causes the foramen ovale to close?
- Pressures dropping on the right side of the heart cause it to close (no more high pulmonary pressures d/t oxygen entering lungs)
Why do the ductus ateriosus and umbilical arteries close in newborns?
- It closes because both have muscles that detect oxygen and prostaglandins
- The increase in oxygen from the lungs and the decrease in prostaglandins from the placenta causes the muscles to clamp down closing them
What is the most common congenital condition?
- Congenital heart disease
Which sex has higher mortality from congenital heart defects?
- Males
Which demographic group has a higher prevalence of congenital heart defects?
1) Hispanic newborns
2) Black newborns
3) Indigenous newborns
4) Non-hispanic white newborns
4) Non-hispanic white newborns have the higest rates of congenital heart disease in both children and adults
Among black infants with parents on public health insurance, what is the risk of death from congenital heart defects from the neonatal period to the post-natal period? Why is it this way in the post-natal period?
- Prenatally: 40% less risk of death on public health insurance than private
- Post-natally: 70% higher risk of death with public health insurance than private
- Hypothesized that the increase is due to the presentation of congenital heart defects and issues with access to appropriate care
True or false: There are currently more adults living with congential heart defects than children
True: There are more adults living with a congenital heart defect than children
Which pulses (where) are palpated in infants?
1) Brachial
2) Femoral
3) Pedal
What percentage of fetuses have no risk factors predisposing them to congenital heart disease?
1) 70%
2) 50%
3) 25%
4) 5%
1) 70%
- Most babies born with CHD do not have risk factors
Which has higher pressures, the atria or ventricles?
The ventricles