Final answer:
The baroreceptors of the aortic arch are innervated by the vagus nerve. They are located in the aortic sinuses and are key to the regulation of blood pressure through the baroreceptor reflex.
Step-by-step explanation:
The baroreceptors of the aortic arch are innervated by the vagus nerve. These baroreceptors play a crucial role in regulating blood pressure by responding to the stretch in the blood vessel walls caused by the blood pressure.
Baroreceptors are sensory receptors that are sensitive to the pressure of the blood as it stretches the walls of the vessels. Their main function is to send signals to the brain to maintain a stable blood pressure, through what is known as the baroreceptor reflex. The baroreceptors that are found in the aortic arch specifically send their signals via the axons that are part of the vagus nerve. This is in contrast to baroreceptors found in the carotid arteries, which utilize axons from the glossopharyngeal nerve.
The aortic sinuses are small pockets in the ascending aorta just above the aortic valve. These are where the baroreceptors are located and are essential for the reflex that aids in regulating vascular homeostasis. When the pressure inside the aorta is high, the baroreceptors send more frequent signals, leading to a decrease in heart rate and vessel dilation, which lowers blood pressure. Conversely, when blood pressure drops, the signal rate decreases, which can prompt an increase in heart rate and vessel constriction to raise blood pressure.