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.
There are different reasons that gums may start to bleed during brushing, some are temporary and some are of more concern. If you are worried about your oral health, then make an appointment with your dentist. Gingivitis. Gingivitis is the first stage of gum disease. Plaque on your teeth and at the gumline that is not removed by brushing and flossing can infect the gums and lead to the symptoms of gingivitis. When gingivitis occurs, your gums may become swollen, tender and sometimes bleed during brushing.