The opening that connects the right and left atria in the fetal heart is the ________.

A) interatrial septum
B) septum primum
C) septum secundum
D) foramen ovale
E) foramen rotundum

Foramen Ovale

In the fetal heart, the oval opening in the septum secundum; the persistent part of septum primum acts as a valve for this interatrial communication during fetal life; postnatally, the septum primum becomes fused to the septum secundum to close the foramen ovale, forming the fossa ovale.

Septum Primum

First septum in the embryonic heart that arises on the wall of the originally single atrium of the heart and separates it into right and left chambers.

Interatrial Septum

The wall of tissue that separates the right and left atria of the heart.