Question

Interauricular septum in the embryonic stages has a/an
A)Foramen ovale
B)Fenestra ovalis
C)Fenestra rotunda-
D)Inter-auricular aperture

Answer 1

Hint: It is a normal opening between the upper two chambers that is the right atrium and the left atrium of an unborn baby's heart. It generally closes 6 months to a year after the baby's birth. It allows blood to cross the atria and bypass pulmonary circulation during fetal development.

Complete answer:
-There is an aperture in the inter-auricular septa of an embryonic heart known as foramen ovale. This aperture generally closes after birth.
-The foramen ovale allows blood to flow from the right atrium to the left atrium during fetal development.
-The oxygenated blood at the placenta is moved away from the pulmonary circulation through the foramen ovale as the lung gets collapsed and becomes non-functioning and bathed in amniotic fluid.
-When the child is born, lungs expand by the neonate through the ventilatory efforts which result in an acute traumatic decrease in the intrathoracic pressure and allow a greater flux of blood to penetrate the pulmonary vessels.
-There is higher pressure in the left atrium by the increased pulmonary venous flow from the lungs causes the septum primum of the interatrial septum to close the opening. By the time, the tissue will block the foramen and become the fossa ovalis

Additional Information: When the foramen ovale is not completely or correctly close. It will lead to multiple conditions from a foramen ovale to atrial septal defects.
-Fenestra ovalis- also known as the oval window, it is a connective tissue membrane that is located at the end of the middle ear and at the beginning of the inner ear.
Fenestra rotunda- It is located below and a little behind the fenestra vestibuli, from where it is separated by a rounded elevation of the promontory. Its function is to transmit the sound waves to the cochlea after the fenestration of the Labyrinth.

So, the correct answer is,” Foramen ovale”

Note: -The foramen ovale is an opening in the muscular tissue present between the left and the right atrium. It allows blood to cross the artery and bypass the pulmonary circulation during fetal development.
-The tissue surrounding the foramen ovale consists of smooth muscle which is derived from the septum primum and septum secundum.