Occlusionofplacentalcirculation

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Unformatted text preview: e a patent ductus arteriosus Biochemical influence, eg: mediation by bradykinin on smooth muscle of DA Bradykinin chemical mediation helps close ductus arteriosus TGF-β probably involved in closure of DA after birth. Occlusion of placental circulation Occlusion of placental circulation Constriction of sphincter of ductus venosus- directs the blood in the umbilical vein to the liver sinusoids Ductus venosus changes slowly into ligamentum venosum . -Foramen ovale is closed; due to higher pressure in the left atrium(increased pulmonary blood flow)than in the right atrium -over lapped parts of septum primum is pressed against the lower part of septum secondum -lower part of septum primum is the area of the fossa ovalis. -Lower margin of septum secundum/crista dividens becomes the limbus. Ductus arteriosus derives from distal part of Lt. 6th arch artery, Ductus - functional closure occurs soon(mostly within 48 hours – some may go on to up til 98 hours) after birth in full term infants - as a result of - contraction of muscular in its wall (DA)– - which...
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