7. Explain the signal transduction pathway that involves the second messenger Ca2+ beginning with the binding of the ligand.

How does the closing of the ductus arteriosus and ductus venosus alter circulation in an infant? a. increases blood flow to the pulmonary artery and increases blood flow to the umbilical vein b. increases blood flow to the pulmonary artery and reduces blood flow to the umbilical vein c. reduces blood flow to the pulmonary vein and increases blood flow to the umbilical artery d. reduces blood flow to the pulmonary vein and reduces blood flow to the umbilical artery