The ductus arteriosus is a hole that allows the blood to skip the circulation to the lungs. However, when the baby is born, the blood must receive oxygen in the lungs and this hole is supposed to close. If the ductus arteriosus is still open (or patent) the blood may skip this necessary step of circulation. The open hole is called the patent ductus arteriosus.
Caring for a Bleeding Tooth. Some people mistakenly think that while brushing, a bleeding tooth is perfectly normal. It is not. Anytime there is any bleeding in the mouth, it is almost always a sign of periodontal disease. Even if you brush fairly hard, it should not cause healthy teeth and gums to bleed.
As you can see, there are many reasons gums bleed. However, almost all these problems involve plaque or bacteria that mixes with food and settles around the gum line. In most cases, bleeding gums (whether because of poor oral hygiene or tooth positioning) are exacerbated by plaque. My main advice is to see your dentist. General restorative dentists or specialists can take a set of dental X-rays and do a full examination to diagnose your problem.