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Changes in the fetus after birth (The two important events)

Immediately after birth two important events occur
  1. Cutting of the umbilical cord
  2. Changes in the lungs after the first breaths.

These two events trigger major functional adaptations in the fetal circulatory system that is given below

  • Blood flow through ductus venosus is eliminated
  • Pulmonary circulation bed expands - which reduce blood flow through ductus arteriosus
  • There is physiological closure of interatrial shunt
  • The closure of ductus venosus in liver is prolonged

Fetal structure produces some remnant in adult
  1. Foramen ovale -fossa ovalis.
  2. Umbilical vein (intra-abdominal part) -ligamentum teres.
  3. Ductus venosus-ligamentum venosum.
  4. Umbilical artery  distal part-lateral umbilical ligaments; proximal part of superior vesical artery.
  5. Ductus arteriosus-ligamentum arteriosum.