The Placenta, Cardiac, and Neuro Development Flashcards
What is the placenta?
An organ that allows the fetus to receive dissolved gases from the mother
What is the chorion?
The outer membrane surrounding the amnion that has villi and allows transfer of nutrients between mother and baby
What is the amnion?
The innermost part of the placenta and lines the amniotic cavity (amniotic sac)
What is Wharton’s Jelly?
The gelatinous substance that surrounds and protects the umbilical cord
What are the functions of the placenta?
It is respiratory, allows excretion of wastes, provides nutrients, is a barrier between mother and baby’s blood, and plays an immunological role for baby
What role do chorionic villi play in gas exchange between mother and baby?
They increase the surface area for gas diffusion in the placenta
What maternal vessels feed the placenta?
Uterine arteries
How is fetal hemoglobin different from adult hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen because there is a different amino acid in the Hb structure.
What is a normal O2 saturation and PaO2 for a fetus and why?
78% or 30mmHg because there is a left shift on the curve meaning the hemoglobin is more saturated at the same PaO2 when compared to adults (an adult’s corresponding sats would be MUCH lower)
What is the double Bohr effect?
Because the fetal Hb has a higher affinity for oxygen, oxygen will leave maternal blood more readily and diffuse to the fetal side. A decrease in the concentration of CO2 in the fetal blood causes more fetal Hb to pick up oxygen diffusing across
When does a heart begin to pump in a fetus?
A single chambered heart begins to pump at 4 weeks
When is development of the heart complete?
9-10 weeks gestation
What is the brainstem made of?
The neural plates and neural tube
What is the germinal matrix?
A temporary blood supply to the brain that appears at 8-9 weeks and is gone by 32-34 weeks
How can brain development determine viability?
The appearance of gyri and sulci can determine viability (MRI if possible as ultrasound is not very accurate)
