The septum transversum contributes to the formation of which structure?

The septum transversum contributes to the formation of which structure?

• A. Heart
• B. Lungs
• C. Diaphragm
• D. Spleen

Answer: (C)

The main idea here is how the diaphragm develops. The septum transversum is an early sheet of mesoderm that sits at the frontier between the thoracic and abdominal cavities. As the embryo folds, this structure becomes the central tendon of the diaphragm—the nonmuscular, central portion that anchors the diaphragm. The muscular part of the diaphragm, by contrast, comes from muscle cells that migrate in from the cervical somites and integrate with surrounding diaphragmatic components. So the septum transversum is best understood as the source of the diaphragm’s central tendon, which is essential for the diaphragm’s overall structure and function in breathing. Other organ systems have different embryologic origins: the heart forms from the primitive heart tube, the lungs develop from foregut endoderm with surrounding mesoderm, and the spleen arises from mesenchyme in the dorsal mesogastrium.

The main idea here is how the diaphragm develops. The septum transversum is an early sheet of mesoderm that sits at the frontier between the thoracic and abdominal cavities. As the embryo folds, this structure becomes the central tendon of the diaphragm—the nonmuscular, central portion that anchors the diaphragm. The muscular part of the diaphragm, by contrast, comes from muscle cells that migrate in from the cervical somites and integrate with surrounding diaphragmatic components.

So the septum transversum is best understood as the source of the diaphragm’s central tendon, which is essential for the diaphragm’s overall structure and function in breathing. Other organ systems have different embryologic origins: the heart forms from the primitive heart tube, the lungs develop from foregut endoderm with surrounding mesoderm, and the spleen arises from mesenchyme in the dorsal mesogastrium.