M7U6: AMNIOTIC FLUID Flashcards
What is amnion composed of ?
A single layer of cuboidal epithelial cells
What are the primary functions of the amniotic fluid ? (5)
- Exchange of water and chemicals (electrolytes, nitrogenous compounds, proteins, enzymes, lipids and hormones) between the fetus and maternal circulation
- Permit proper fetal lung development
- Stabilization of temperature to protect the fetus from extreme temperature changes
- Allows fetal movement
- Serves as a protective cushion for the fetus
How is the volume of amniotic fluid regulated ? (3)
- Production from fetal urine and lung fluid
- Absorption from fetal swallowing
- Intramembranous flow
What is intramembranous flow of amniotic fluid ?
Absorption of amniotic fluid water and solutes into the fetal blood
What is the volume of amniotic fluid at 12 weeks of gestation ?
25-50 mL
What is the volume of amniotic fluid at 37 weeks of gestation ?
800-1200 mL
When does amniotic fluid formation start in pregnancy ?
The first trimester
___ mL of amniotic fluid produced during the first trimester is produced by the ___ and ___ that is derived from the ___
35
Amnion and placenta
Maternal circulation
As the gestation progresses in amniotic fluid formation, water and solutes exchange between the fetus and the amniotic fluid through ? (3)
- Fetal urination
- Intestinal absorption following fetal swallowing of amniotic fluid
- Capillary exchange in the pulmonary system alveoli, as the alveoli of the fetal lungs are bathed with amniotic fluid
Under formation of amniotic fluid, in the later stages of pregnancy, ___ and ___ play a significant role in the amniotic fluid volume and composition
Fetal swallowing
Urination
___ removes water and electrolyte from the amniotic fluid and replaces them through urination with metabolic by-products such as ___, ___, and ___
Fetal swallowing
Urea
Creatinine
Uric acid
How is maternal plasma and amniotic fluid exchange similar to fetal swallowing ?
Maternal plasma removed metabolic waste products and replenishes them with water, nutrients, and electrolytes
___ is associated with decreased fetal swallowing
Polyhydramnios
What is the main diagnosis for polyhydramnios ?
Neural tube defect (NTD)
Polyhramnios often indicate fetal distress and congenital malformations in ___ (3)
NTD
rapidly growing fetal edema
Hydrops fetalis
Polyhydramnios is secondarily associated with ___ (4)
- Fetal structure anomalies
- Cardiac arrythmias (fetal heart failure)
- Congenital infections
- Chromosomal abnormalities
Polyhydramnios is the term if the amniotic fluid volume exceeds ___ mL
1,200
Oligyhydramnios is the term if the amniotic fluid volume is below ___ mL
800
___ is associated with increased fetal swallowing
Oligohydramnios
Oligohydramnios has a possible indication of ___ (6) resulting in ___ and ___
- Urinary tract deformities
- Membrane leakage
- Donor twin transfusion syndrome
- Congenital malformation
- Premature rupture of the amniotic membrane
- Umbilical cord compression
Decreased heart rate and fetal death
What is the ultimate source of amniotic fluid water and solutes ?
Placenta
The presence of ___ and ___ is significant because these components serve as biochemical markers to detect NTD
Alpha-fetoprotein
Acetylcholinesterase
Once fetal production begins an increase in concentration can be seen in ___ (3)
creatinine
urea
uric acid
Once fetal production begins a decrease in concentration can be seen in ___ (2)
glucose
protein
