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.
Bleeding gums could be a sign of a number of dental problems, but it's usually a symptom of gum disease. In some cases, the causes of bleeding gums may be the result of injuries or infections of the teeth. Gum disease usually isn't painful, so many people don't know they have it until it advances. Being aware of the symptoms can help you catch gum disease early -- and possibly reverse it through gum disease treatment.