A developing fetus does not use its lungs for gas exchange. At birth, several significant changes occur in the anatomy of the respiratory system.
Before delivery, pulmonary arterial resistance is high because the pulmonary vessels are collapse
Before delivery, the rib cage is compressed, lungs and conducting passageways contain only small amounts of fluid and no air
First breath pushes fetal fluids out of the way, inflates entire bronchial tree and most of alveoli, drop in pressure pulls air into lungs and blood into pulmonary circulation
First breath, changes in blood flow cause the foramen ovale and the ductus arteriosus to close
SUMMARY
Before delivery, fetal lungs are fluid filled and collapsed. At first breath, the lungs inflate and never collapse completely thereafter.
Summarize the changes that occur in a newborn infant's cardiovascular and respiratory systems as a newborn infant starts to breathe.
During a baby's first breath, air if forced into the lungs due to the change in pressure.Fluids are pushed out of the way of the conducting passageways, and the alveoli immediately inflate with air. Pulmonary circulation becomes activated, and this closes the foramen ovale and the ductus arteriosus.
