Embryonic
The pulmonary circulation loop is virtually bypassed in fetal circulation. The fetal lungs are collapsed, and blood passes from the right atrium directly into the left atrium through the foramen ovale, an open passage between the two atria. When the lungs expand at birth, the pulmonary pressure drops and blood is drawn from the right atrium into the right ventricle and through the pulmonary circuit. Over the course of several months, the foramen ovale closes, leaving a shallow depression known as the fossa ovalis in the adult heart.
Read more about this topic: Pulmonary Circulation
Famous quotes containing the word embryonic:
“Quintilian [educational writer in Rome around A.D. 100] thought that the earliest years of the child’s life were crucial. Education should start earlier than age seven, within the family. It should not be so hard as to give the child an aversion to learning. Rather, these early lessons would take the form of play—that embryonic notion of kindergarten.”
—C. John Sommerville (20th century)