Septum secundum

Septum secundum is an anatomical structure in the heart that plays a crucial role in the development of the heart's septal structure, which separates the right and left sides of the heart. This separation is essential for the proper direction of blood flow through the heart and the circulatory system. The septum secundum is part of the atrial septum, which divides the heart's atria, and its development and function are critical for normal heart physiology and embryonic heart development.

Development

The heart begins to develop early in embryonic life, with the septum secundum forming after the initial development of the Septum primum. As the septum primum grows towards the endocardial cushions, which eventually divides the atria from the ventricles, a second septal structure, the septum secundum, begins to form to the right of the septum primum. The septum secundum grows downward, partially overlapping the septum primum but leaving an opening known as the foramen ovale. This opening allows blood to flow directly from the right atrium to the left atrium, bypassing the fetal lungs, which are not yet in use as the fetus receives oxygenated blood from the placenta.

Function

During fetal development, the septum secundum's role is primarily in facilitating the correct flow of blood. The foramen ovale, bordered by the septum secundum, is a crucial component of fetal circulation. After birth, when the lungs expand and the infant begins to breathe air, the pressure changes in the heart lead to the closure of the foramen ovale. The septum primum and septum secundum press together, sealing the opening and thus separating the atria completely. This process completes the separation of the systemic and pulmonary circulations, which is essential for efficient oxygenation of blood in the lungs.

Clinical Significance

In some cases, the foramen ovale does not seal properly after birth, a condition known as a Patent foramen ovale. This condition can lead to a number of complications, including the potential for paradoxical emboli, where a blood clot passes from the right side of the heart to the left, bypassing the lungs and potentially causing a stroke. The septum secundum's development and the dynamics of its interaction with the septum primum are areas of interest in understanding congenital heart defects and their treatments.

Treatment and Management

The management of conditions related to the septum secundum, such as a patent foramen ovale, depends on the severity and the presence of symptoms or complications. In many cases, a patent foramen ovale may be left untreated if it is not causing significant problems. However, in cases where treatment is necessary, options may include medical management with anticoagulants to prevent clot formation or procedural interventions such as a percutaneous closure of the foramen ovale.

See Also

• Heart development
• Atrial septal defect
• Congenital heart defect