atrial septum development

Definition

Target type: biologicalprocess

The progression of the atrial septum over time, from its initial formation to the mature structure. [GOC:mtg_heart]

The atrial septum, a crucial structure separating the left and right atria of the heart, undergoes a complex developmental process. Its formation is essential for preventing mixing of oxygenated and deoxygenated blood, a critical step in proper fetal circulation. The development of the atrial septum is characterized by the interplay of multiple cellular events, including proliferation, migration, and differentiation, driven by intricate signaling pathways.

The process initiates with the formation of the septum primum, a crescent-shaped tissue that grows from the dorsal roof of the primitive atrium. This structure is initially attached to the endocardial cushions, serving as a temporary barrier between the atria. As the septum primum grows towards the ventricular septum, it gradually reduces the opening known as the ostium primum, leading to a separation of the atria.

Concurrently, a second structure, the septum secundum, develops adjacent to the septum primum, forming a larger, crescent-shaped flap that partially overlaps the ostium primum. This overlapping arrangement creates an opening known as the foramen ovale, facilitating the passage of blood from the right to the left atrium, bypassing the fetal lungs.

As the septum primum continues to grow and eventually fuses with the endocardial cushions, the ostium primum closes. The foramen ovale, however, remains open during fetal development, allowing the passage of oxygenated blood from the placenta directly to the systemic circulation. This shunt is crucial for bypassing the non-functional fetal lungs.

After birth, the increased pressure in the left atrium forces the septum primum against the septum secundum, effectively closing the foramen ovale and establishing the definitive separation between the atria. This closure is usually permanent, although a small residual opening, called the fossa ovalis, may remain.

The development of the atrial septum is a precise and complex process, intricately regulated by a diverse array of genetic and molecular factors. Any disruption in this delicate balance can lead to congenital heart defects, including atrial septal defects (ASDs), which can range in severity and require various treatments.

Overall, the formation of the atrial septum is a crucial step in the development of a functional heart, essential for maintaining the separation of oxygenated and deoxygenated blood streams and ensuring the appropriate circulation of blood throughout the body.'
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Proteins (2)

Compounds (19)