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

Separate the vessel into its lining and its muscular coat, then assign each layer to a mesodermal source. The inner endothelium of the dorsal aorta grows from angioblasts, but the question targets the muscular wall, so focus on what supplies smooth muscle and connective tissue around the trunk aorta.

The paraxial mesoderm, organised into somites and their sclerotomes, lies right alongside the developing dorsal aorta and contributes the vascular smooth muscle of its wall in the trunk region. The septum transversum is committed to the diaphragm and liver, so it is irrelevant here. The intermediate mesoderm is reserved for kidneys and gonads. The lateral plate mesoderm gives rise to body wall and gut smooth muscle and serous linings, but not to the muscular coat of the dorsal aorta in the trunk. With the muscular wall traced to the neighbouring somitic tissue, paraxial mesoderm is the source.
\[\boxed{\text{Paraxial mesoderm}}\]