# Select the incorrect statement about the carotid sinus:
A. It is a dilatation near the beginning of the internal carotid artery
B. It is innervated by the glossopharyngeal nerve
C. It acts as a chemoreceptor
D. Its wall has thick tunica adventitia
The correct answer is C. It acts as a chemoreceptor; which is incorrect because carotid sinus is a baroreceptor.
Carotid Sinus : The termination of the common carotid artery, or the beginning of the internal carotid artery shows a slight dilatation, known as the carotid sinus which receives a rich innervation from the glossopharyngeal and sympathetic nerves. The carotid sinus acts as a baroreceptor or pressure receptor and regulates blood pressure.
Carotid Body: Carotid body is a small, oval reddish-brown structure situated behind the bifurcation of the common carotid artery. It receives a rich nerve supply mainly from the glossopharyngeal nerve, but also from the vagus and sympathetic nerves. It acts as a chemoreceptor and responds to changes in the oxygen and carbon dioxide and pH content of the blood.
