Normal changes in pulmonary circulation after birth are the ...

[pane00]

Normal changes in pulmonary circulation after birth are the result of:
 
  a. Closure of the pulmonary artery
  b. Opening of the ductus venosus
  c. Low pressure in left heart chambers
  d. Closure of the ductus arteriosus

Question 2

The effect of decreased PO2 and increased PCO2 on the newborn infant is to:
 
  a. Cause the fetal shunts to close.
  b. Suppress metabolic processes.
  c. Promote chest compression and recoil.
  d. Stimulate the brain to begin respirations.

[tennis14576]

Answer to Question 1

ANS: D
After birth, the ductus arteriosus and the ductus venosus close. The pulmonary artery does not close. If it were to close, the oxygenated blood could not flow to the lungs for oxygenation. The pressure in the right side of the heart rises, causing the foramen ovale to close.

Answer to Question 2

ANS: D
After the umbilical cord is cut, the infant experiences temporary hypoxia and acidosis. The changes in arterial oxygen, carbon dioxide, and pH activate the respiratory center in the medulla of the brain to initiate respirations.