Which structure in the fetus allows blood to be shunted from the right atrium to the left atrium?
A) Foramen ovale
B) Ductus venosus
C) Ductus arteriosus
D) Umbilical vein

Question

Quizplus · Accepted Answer

The foramen ovale is a small opening between the right and left atria of the fetal heart that allows oxygen-rich blood from the placenta to bypass the non-functioning fetal lungs and flow directly into the left atrium. This shunting of blood helps to maximize oxygen delivery to the developing brain and other vital organs, and is facilitated by the pressure differences between the two atria, as well as by special muscular flaps that act like a one-way valve to prevent backflow of blood from the left to the right atrium. After birth, with the initiation of breathing and the expansion of the lungs, the pressure in the left atrium increases, causing the flaps to fuse together and seal the foramen ovale permanently, thus ensuring proper separation of the systemic and pulmonary circulations.

Which Structure in the Fetus Allows Blood to Be Shunted