Diffusion through placental membrane Flashcards
Simple diffusion from sinuses through villus membrane down pressure gradient to fetus
from maternal blood − _____ mm Hg
mean PO2 in villus _____mm Hg
mean PO2 in fetal blood _____mm Hg
from maternal blood − 100 mm Hg
mean PO2 in villus − 50 mm Hg
mean PO2 in fetal blood − 30 mm Hg
Fetal Hb (Hb F- 22) has higher affinity for O2: can carry ____more O2 than maternal Hgb
20-30%
____shift of Oxy-Hb curve (newborn) ; later shift to ____
left, right
Fetal Hb concentration in blood is ____ greater than in mother
50%
Anemia when Hb ___g/dl (newborn) and ___ g/dl in older than 3 months
<13, < 10
CO2: builds up until it is slightly higher in fetus umbilical arteries_____ than in intervillous space ______
(48 mm Hg), (43 mm Hg)
Affinity for CO2 is _____ in fetus, favoring transfer from fetus to mother
lower
Receptor mediated endocytosis from mother: ____
LDL
Renin increases late in gestation due to
- Renal sympathetic nerve activity
- Reduction in Na and blood volume
- Change in renal perfusion pressure
Diagnosis of fetal well-being:
Noninvasive
Transvaginal ultrasound: visualize vertebrae, kidneys,
bladder, fingers and toes by 12 wks gestation
Diagnosis of fetal well-being
Invasive
Amniocentesis: 14-16 wks; when amniotic cavity contains 150-200 ml (remove 20 ml); with simultaneous ultrasound; karyotyping, biochemical analyses, DNA
cytogenetic and biochemical testing recommended after 10 wks gestation; usually 2nd and 3rd trimester
Chorionic villus sampling
transabdominal; from 17 wks into umbilical vein about 1 cm from placental cord insertion site
Fetal blood sampling