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Plan of the fetal circulation ("Ductus arteriosus" visible at upper right)
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Heart cross-section with PDA
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In the developing
Fetus , the ('''DA''') is a
Shunt connecting the
Pulmonary Artery to the
Aortic Arch that allows most of the
Blood from the
Right Ventricle to bypass the fetus' fluid-filled
Lung s. During
Fetal Development , this shunt protects the lungs from being overworked and allows the right ventricle to strengthen. There are two other fetal shunts, the
Ductus Venosus and the
Foramen Ovale .
The ductus arteriosus is sometimes called the , after
Leonardo Botallo , although the discovery should have been attributed to
Giulio Cesare Aranzi , to whom (less commonly) the
Ductus Venosus is named.
When the ion of the
Smooth Muscle in wall of the DA, reducing flow. Bradykinin works by acting on eNOS to increase NO produced, thus inducing vasodilatation. ACE breaks down bradykinin and therefore, ACE inhibitors aid in prolonging the action of vasodilatation by bradykinin. Additionally, because of reduced pulmonary resistance, more blood flows from the pulmonary arteries to the lungs and thus the lungs deliver more
Oxygen ated blood to the left heart. This further increases aortic pressure so that flow in DA may
Transient ly reverse.
Usually, the DA begins to close when breathing is established, and is completely sealed after four to ten days. A cord-like of the DA, called the
Ligamentum Arteriosum , remains to connect the exterior of the
Left Pulmonary Artery to the exterior of the aortic arch.
When the
Ligamentum Arteriosum forms it traps the left branch of the recurrent left vagus nerve in the thorax.
See Also: Patent ductus arteriosus
Failure of a child's DA to close after birth results in a condition called
Patent Ductus Arteriosus and the generation of a
Left-to-right Shunt . If left uncorrected, patency leads to
Pulmonary Hypertension and possibly
Congestive Heart Failure and
Cardiac Arrhythmia s. Closure may be induced with a drug class known as
NSAIDs such as
Indomethacin or
Ibuprofen because these drugs inhibit prostaglandin synthesis.
Prostaglandins are responsible for maintaining the ductus arteriosus.
