Fetal circulation:Thebloodcirculationinthefetus(未出生的婴儿)。在我们出生之前,体内的血液从场效应晶体管al heart that is destined for thelungsis shunted away from the lungs through a shortvesselcalled theductus arteriosusand returned to theaorta. When thisshuntis open, it is said to be apatent ductus arteriosus(PDA). The PDA usually closes at or shortly after birth, allowing blood to course freely to the lungs.
