Question

outline the major changes that occur in the heart after birth. Include the location of these changes and the significance of each for both the fetus and the newborn

Answer 1

1. the ductus arteriosus is transformed into the ligamentum arteriosum (by fibrous tissue proliferation of tunica intima)

ductus arteriosus helps in shunting the blood from pulmonary arteries to aorta. ligamentum arteriosum for the connection with aortic arch. if the ductus arteriosus won't close after duct, the deoxygenated blood will get mixed with the aortic oxygenated blood.

2. foramen ovale is obliterated and the site is marked permanently by the fossa ovalis. this is caused by the increased pressure in the left atrium. this is because of the ending of a placental circulation and a sharp increase in the volume of blood returning from the lungs. with the first breath, the septum primum is pressed against septum secundum. constant apposition gradually leads to the fusion of the 2 septa in about a year.

foramen ovale acts as a shunt to bypass the blood from going to lungs, found at the junction of right and left atrium. fossa ovalis prevents the mixing of deoxygenated and oxygenated blood.

3. the umbilical vessels pass into sudden and complete disuse by contraction of smooth musculature of the walls. the arteries become transformed into round ligaments of the bladder ligamentum teres of the urinary bladder and the veins form the ligamentum teres of the liver ( anatomically by fibrous tissue proliferation of tunica intima).

the umbilical vessels were used for efficient fetal circulation, which returns the deoxygenated blood and takes oxygenated blood to the fetus. ligamentum teres help in abduction, flexion, and rotatory movements of the hip and it supplies blood to the femoral head.

4. the ductus venosus also trophies and is transformed into the fibrous ligamentum venosum embedded in the wall of the liver.

ductus venosus helps in shunting the oxygenated blood from the veins of the umbilicus to the inferior vena cava. ligamentum venosum helps in circulating the deoxygenated blood from the liver to inferior vena cava.