NUR 323 Lecture Notes - Lecture 3: Peristalsis, Polycythemia, Hemoglobin
Document Summary
Intrapulmonary fluid: secretion as infant approaches term, absorption during labor & delivery / few hours after birth, decreased intrapulmonary fluid, reduces pulmonary resistance to blood flow. Production / release of surfactant: usually sufficient amount by 34-36 weeks gestation, rds may occur in infants with immature lungs, betamethasone if preterm birth expected. Lung expansion after birth stimulates the release of the surfactant. Surfactant decreases surface tension within alveoli: allows alveolar re-expansion after exhalation. Internal stimuli: chemical factors: hypercarbia, acidosis and hypoxia. Sensory factors: sensory overload touch, sound, light. Thermal factors: temperature changes (warm to cool: mechanical factors: removal of fluid from lungs and replacement with air. Closure of ducts: foramen ovale, ductus arteriosus, and ductus venosus. Placenta: provides oxygen and nutrients to fetus; eliminates waste. Three shunts allow circulation to bypasses fetal lungs and fetal liver. Lungs: foramen ovale moves blood from r atrium to l atrium ductus arteriosus moves blood from the pulmonary artery to the aorta.
