The ductus aeriosus closes anatomically within:-: (A) Immediately after bih, (B) 7 days after bih, (C) 4-6 weeks after bih, (D) 10 - 21 days after bih
Answer is D. - Anatomical closure of ductus aeriosus occurs within 10 to 21 days after bih. Occurs by proliferation of its intima cells - Functional closure of ductus aeriosus occurs immediately after bih by smooth muscle contraction which occurs as a result of increase in oxygen saturation.