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The baroreceptors are the pressure sensors which respond to the changes in the blood pressure. The baroreceptors are located in the aortic arch and carotid sinus. Carotid sinus has abundance of glossopharyngeal nerve fibres in the tunica externa and thin tunica media. Any change in the vascular pressure activates the baroreceptors. This leads to the modulaton of transmission of impulses through the sensory fibers to the vasomotor center located in the medulla oblongata. Activation of vasomotor center causes increase in firing rate of central sympathetic discharge to the periphery, hence the cardiac output and blood pressure increases. In case of increase in blood pressure, the sympathetic discharge to the periphery is decreased through the vasomotor center. Hence, the blood pressure decreases. Thus, the too much increase in blood pressure in the brain is prevented.