Question

In a mammalian embryo, the pulmonary aorta communicates with the carotid-systemic aorta by a narrow ductus arteriosus, in the adult this connection closes leaving
(a)Fossa-ovalis
(b)Carotico pulmonary aperture
(c)Ligamentum arteriosus
(d)None of the above

Answer 1

The pulmonary aorta connects with the carotid-systemic aorta in a mammalian embryo through a narrow ductus arteriosus, leaving the part closely connected to the left recurrent laryngeal nerve in the adult. In Latin, this section means arterial ligament.

Complete answer:
The ductus arteriosus is a blood vessel in the developing fetus that links the pulmonary artery to the proximal descending aorta, also called the ductus Botalli. It helps much of the blood from the right ventricle to bypass the non-functioning lungs of the fetus filled with fluid. It becomes the ligamentum arteriosum following closure at birth. The remnant of ductus arteriosus is Ligamentum arteriosum. Ductus arteriosus is a narrow channel linking the lumen of the two arches at the time of birth, which is closed.
The ligamentum arteriosum is a small ligament developed within three weeks of birth, which is the residue of the ductus arteriosus.
The ligamentum arteriosum, a branch of the left vagus nerve, is closely connected to the left recurrent laryngeal nerve. The left recurrent laryngeal coils around the aortic arch behind the ligamentum arteriosum after separating from the left vagus nerve, after which it ascends to the larynx.
This ligament also plays a part in major trauma; during sudden movements, it fixes the aorta in place, possibly resulting in a ruptured aorta.
The place where the ligamentum arteriosum (the remnant of the ductus arteriosus) connects to the aorta is the most common site of aortic transection. The ligamentum arteriosum functions as a tether that holds tight to each other the aorta and pulmonary artery.
So, the correct answer is, ‘Ligamentum arteriosus’.

Note: In the developing fetus, the ductus arteriosus, also known as the Botalli duct, named after Leonardo Bottallo, an Italian physiologist, is a blood vessel that connects the pulmonary artery trunk to the descending proximal aorta. It helps much of the blood from the right ventricle to bypass the non-functioning lungs of the fetus that are fluid-filled. It becomes the ligamentum arteriosum following closure at birth.