Question

Muscular component of dorsal aorta develops from?

• A. Septum transversum
• B. Paraxial mesoderm
• C. Intermediate mesoderm
• D. Lateral plate mesoderm

Hint:

Somite-derived paraxial mesoderm supplies the trunk dorsal aorta smooth muscle.

Answer 1

The Correct Option is B

Step 1: Recall the subdivisions of mesoderm. The intraembryonic mesoderm organises into paraxial mesoderm (somites), intermediate mesoderm, and lateral plate mesoderm (splanchnic and somatic layers).
Step 2: Trace the origin of vessel walls. The endothelial lining of the dorsal aorta arises from angioblasts of splanchnic mesoderm, but the surrounding smooth muscle and connective tissue of the vessel wall in the trunk are contributed by the sclerotome derivatives of the paraxial mesoderm (the somites adjacent to the aorta).
Step 3: Eliminate the wrong choices. The septum transversum is a mesodermal mass that forms the central tendon of the diaphragm and part of the liver, not the aortic wall. The intermediate mesoderm forms the urogenital system. The lateral plate mesoderm forms the body wall, limb connective tissue, serous membranes and the smooth muscle of the gut, not the muscular coat of the dorsal aorta in the trunk.
Step 4: Conclusion. The muscular component of the dorsal aorta is derived from paraxial mesoderm.
Hence the correct answer is option B.