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.
What causes bleeding gums? Bleeding gums are mostly caused by gingivitis which is an infection or inflammation of the gum, particularly in the tissue around the teeth. Most often the cause of the irritation is from plaque that live in the mouth. Swelling and bleeding when the teeth are brushed or flossed characterize the infection. Plaque can form on any tooth surface, but the accumulation is heaviest between the teeth and along the gum line, areas that are not self-cleaning.