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.
Five Things You Can Do If Your Gums Are Bleeding. You're brushing your teeth and notice a bit of pink when you spit out the toothpaste. You might notice some bleeding when you floss. Although the smallest amount of blood might not seem like a big deal, if your gums are bleeding consistently, you shouldn't ignore it. Bleeding gums can happen for a number of reasons, from gingivitis to a side effect of pregnancy.