Area postrema

The area postrema, also known as the chemoreceptor trigger zone is one of the so-called circumventricular organs located on the dorsal inferior surface of the medulla oblongata at the caudal end of the fourth ventricle.

The specialized ependymal cells in the area postrema detect toxins in the blood and act as a vomit-inducing center, along with the nucleus of the solitary tract and the dorsal motor nucleus of the vagus nerve that make up the dorsal vagal complex.