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Foetal Circulation - Anatomy & Physiology (view source)
Revision as of 16:01, 31 July 2008
, 16:01, 31 July 2008no edit summary
====Closure of the Foramen Ovale====
====Closure of the Foramen Ovale====
In the foetus the foramen ovale is kept open by the higher pressure of blood in the right atrium compared to the left atrium. At birth the blood pressure in the right atrium decreases due to termination of blood flow from the placenta, whilst pressure in the left atrium increases due to increased pulmonary flow. As a result, the flap of the septum primum presses against the septum secundum closing the foramen ovale. In most individuals, the foramen ovale closes a few months after birth. A scar remains between the two atria once the foramen ovale has closed and this is termed the fossa ovalis.
====Closure of the Ductus Arteriosus====