Arteries supplying the pharyngeal arches originate from which part of the primordial heart?

• A. Truncus arteriosus
• B. Aortic arch
• C. Pulmonary trunk
• D. Sinus venosus

Answer: (A)

Arteries that feed the pharyngeal arches arise from the outflow region of the primitive heart, the truncus arteriosus. In early development, the truncus arteriosus gives rise to the aortic sac, which is the origin point for the pharyngeal (aortic) arch arteries that connect to the dorsal aorta and supply the arches. As development progresses, these arches remodel into the adult great vessels, but their source remains the truncus arteriosus via the aortic sac. The pulmonary trunk is also derived from the same outflow tract but serves the pulmonary circulation, and the sinus venosus is a venous structure feeding into the heart, not supplying the arches.