Microanatomical Studies on Ductus Arteriosus with Relation to Foetal Age

Abstract

The present study was conducted on ductus arteriosus in buffalo foetii from 4.2 cm CVRL (48 days) to 99.5 cm CVRL (298 days). At 4.2 cm CVRL, tunica intima was composed of an endothelial cell lining. At 10.5 cm CVRL foetus, all the tunics viz. intima, media and adventitia were well defined. Tunica media became more muscular and composed of loosely arranged smooth muscle fibres in connective tissue matrix containing very fine wavy elastic fibres at 34 cm CVRL. The ductus arteriosus did not show any remarkable changes from 26-40 cm CVRL foetus. The distinguishing feature was the formation of intimal cushions at 50 cm CVRL foetus i.e. 186 days. At 99.5 cm CVRL foetus (298 days) there was decrease in smooth muscle cells and increase in collagenous ground substance resulting in narrowing of lumen and bliteration of ductus arteriosus after birth.