Digital (Finger Press)pressure is Exerted Over the Carotid Sinus

Question

Digital (finger press)pressure is exerted over the carotid sinus.You expect
A) the sympathetics to fire, thereby increasing blood pressure.
B) that the medulla oblongata will interpret the signal as high blood pressure and therefore fire the vagus nerve.
C) no effect, because the baroreceptors are "crushed."
D) reflex tachycardia.

Accepted Answer

Digital pressure applied over the carotid sinus stimulates the baroreceptors present in it. The baroreceptors signal to the brainstem about changes in blood pressure. In response to the signal, the medulla oblongata may activate the vagus nerve to decrease heart rate and lower blood pressure. Therefore, the correct choice is B. A is incorrect because the sympathetic system is not typically involved in the baroreceptor reflex. C is incorrect because the baroreceptors are not "crushed" by the pressure. D is incorrect because reflex tachycardia is not typically observed in response to pressure on the carotid sinus.