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.
Dental Conditions That Can Cause Bleeding Gums. Dental care issues are the primary cause of bleeding gums. Gingivitis (inflammation of the gums) and periodontitis make your gums sensitive and more prone to bleeding. Most people develop gingivitis when plaque remains on the gum line for too long. Plaque refers to the debris and bacteria that stick to your teeth.