During cardiac development, the aorticopulmonary septum (AP septum) divides the truncus arteriosus into the aorta and pulmonary trunk. Which cells migrate into the outflow tract to form this septum?

• A Second heart field cells from the pharyngeal mesoderm
• B Epicardial progenitor cells (proepicardium)
• C Cardiac neural crest cells from rhombomeres 6–8 ✓
• D First heart field cells from the cardiogenic crescent

Explanation

The aorticopulmonary septum that divides the truncus arteriosus into the ascending aorta and pulmonary trunk is formed by migration of cardiac neural crest cells — specifically from rhombomeres 6, 7, and 8 of the hindbrain. These cells migrate through pharyngeal arches 3, 4, and 6 into the outflow tract, forming the spiral AP septum and contributing to the tunica media of the great vessels. Defective cardiac neural crest migration is responsible for conotruncal defects (Tetralogy of Fallot, persistent truncus arteriosus, transposition of great arteries, interrupted aortic arch), as seen in DiGeorge/22q11.2 deletion syndrome.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.