Final answer:
The ductus arteriosus in the fetus becomes the ligamentum arteriosum in adults, a piece of connective tissue that no longer participates in blood circulation.
Therefore, the ductus arteriosus' adult counterpart is Option 4: the Ligamentum arteriosum.
Step-by-step explanation:
Ductus Arteriosus in Adults
The ductus arteriosus is a vital component of fetal circulation, connecting the pulmonary artery with the aorta and directing blood away from the non-functioning fetal lungs. In an adult, the ductus arteriosus transforms into the ligamentum arteriosum after birth.
When the newborn begins to breathe, pressure in the lungs drops, and the ductus arteriosus constricts, leading to the eventual closure of this vessel. Over time, the remnants of the ductus arteriosus form the ligamentum arteriosum, a piece of connective tissue without a direct role in blood circulation.
A patent ductus arteriosus is a condition where the ductus arteriosus fails to close after birth, which can have severe health implications if left untreated, such as congestive heart failure. Treatment options include surgical closure, manual closure with medical devices, or medications to encourage closure.
Therefore, the ductus arteriosus' adult counterpart is Option 4: the Ligamentum arteriosum.