MICROANATOMY

Detailed explanation-1: -The hole between the top two heart chambers (right and left atrium) is called a patent foramen ovale (PFO). This hole allows the oxygen rich blood to go from the right atrium to left atrium and then to the left ventricle and out the aorta. As a result the blood with the most oxygen gets to the brain.

Detailed explanation-2: -The shunts that bypass the lungs are called the foramen ovale, which moves blood from the right atrium of the heart to the left atrium, and the ductus arteriosus, which moves blood from the pulmonary artery to the aorta. Oxygen and nutrients from the mother’s blood are transferred across the placenta to the fetus.

Detailed explanation-3: -The foramen ovale is an aperture in the muscular tissue between the left and right atrium that allows blood to cross the atria and bypass pulmonary circulation during fetal development. The surrounding tissue is composed of smooth muscle derived from the septum primum and septum secundum.

Detailed explanation-4: -There are two structures that allow for this bypass of the lungs. The first structure is encountered in the right atrium. An opening within the atrial septum termed the foramen ovale carries blood from the right atrium directly into the left atrium, thereby bypassing the right ventricle and lungs.

Detailed explanation-5: -Inside the fetal heart. Blood enters the right atrium. This is the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium.