Part 2: Fetal And Neonatal Physiology Flashcards
The fetal lungs develop ___, and there is no respiration during fetal life.
Some respiratory movements will occur and last ____ months.
Inhibited respiratory prevents lungs from filling with ____ and ____.
What secretes small amount of fluid into the lungs until birth?
Slowly
3-4
Fluid and debris
Alveolar epithelium
What is the role of surfactant?
What secretes it?
When does synthesis begin?
Once ___ open, it is harder to close them when exhaling without surfactant.
Decreases surface tension
Type II alveolar epithelial cells
Last trimester
Alveoli
When does breathing being?
What is the stimulus?
What happens if there is delayed breathing upon birth?
Within seconds after brith
Asphyxiation during brith; sudden drop in temperature/cooling of skin
Use of general anesthesia during delivery; prolonged labor; head trauma (depressed respiratory center)
At birth, alveoli collapse, and ______ fills them.
How much negative inspiratory pressure is needed to overcome the surface tension and open the alveoli?
During the 1st inspiration, the infant is capable of ____ pressure. This brings ____ mL of air.
Deflation requires a strong positive pressure and must overcome a viscous resistance of fluid in the ____.
Amniotic fluid
More than 25 mmHg
60 mmHg
40
Bronchioles
The second breath requires less ____.
When does breathing become normal?
Settles into ___ breaths per min (RR).
Tidal volume of ____.
Effort
Until 40min after birth
40
6-10 mL/kg
What can cause hypoxia during delivery?
Neonates have a higher tolerance for hypoxia. Duration between breathing and death: adults ____ and neonates ____.
Compression of umbilical cord
Premature separation of placenta
Excessive uterine contractions
Excessive anesthesia of the mother (depressed maternal breathing)
4min; 8-10min
What is respiratory distress syndrome?
Common in premature infants and infants born to diabetic mothers
Failure to secrete adequate amounts of surfactant resulting in collapsed alveoli and development of pulmonary edema
When does the heart begin to beat?
Initially beats _____ and increases to _____ pre-birth.
4th week after fertilization
65bpm; 140bpm
Fetus receives O2 blood from the _____ and unoxygenated blood from _____.
Umbilical V; umbilical A
What are the four shunts in the fetus?
Placenta, ductus venosus, foramen ovale, ductus ateriosus
Blood flow to the placenta shunts blood away from the ____.
Describe umbilical A and V
Lower trunk
Umbilical A: branch repeatedly, returns deoxygenated blood, dense capillary network at terminal villi, legs connect to IVC
Umbilical V: returns O2 blood to fetus from placenta, blood enters through ductus venosus
The ____ is bypassed by the ductus venosus because this organ is non-functional. It becomes a direct route from umbilical V to IVC.
Liver
The hole in the septum dividing the atria, on the posterior R atrium is ____.
Makes a R atrial shift and bypasses the _____.
_____ goes right through to the L ventricle to supply the carotid and brain.
___ percent of blood is shunted through the foramen ovale
Foramen ovale
R ventricle
IVC
27
J
J
J
J
