Endocardial cushions

Diagram showing the location of endocardial cushions in the developing heart.

The endocardial cushions are specialized structures found in the developing heart of vertebrates, including humans. They play a crucial role in the formation of the heart valves and the septa that separate the different chambers of the heart. The development and proper functioning of the endocardial cushions are essential for the normal functioning of the cardiovascular system.

Structure

The endocardial cushions are composed of a combination of extracellular matrix components, including collagen, elastin, and proteoglycans. They are located in the atrioventricular (AV) canal, which is the region between the atria and the ventricles in the heart. The cushions are formed by the migration and transformation of specialized cells called endocardial cells.

Development

During embryonic development, the endocardial cushions arise from the endocardium, which is the innermost layer of the heart. Initially, the endocardial cushions appear as swellings in the AV canal. As development progresses, these swellings fuse together and undergo remodeling to form the valves and septa of the heart.

Function

The main function of the endocardial cushions is to provide support and structure to the developing heart. They serve as a scaffold for the formation of the heart valves, which ensure the unidirectional flow of blood through the heart. The cushions also contribute to the formation of the atrial and ventricular septa, which separate the left and right sides of the heart.

Clinical Significance

Abnormal development or dysfunction of the endocardial cushions can lead to various congenital heart defects. For example, failure of the cushions to fuse properly can result in atrioventricular septal defects, where there is a hole between the atria and ventricles. These defects can cause significant problems with heart function and may require surgical intervention.

See Also

• Heart Development
• Heart Valve
• Congenital Heart Defects