An increase in stretch in carotid baroreceptors leads to an increased vagus nerve stimulation to the heart: true false
The correct answer and explanation is:
True. An increase in stretch in carotid baroreceptors leads to an increased vagus nerve stimulation to the heart.
Carotid baroreceptors are specialized sensory nerve endings located in the carotid sinus, which is a dilation found at the base of the internal carotid artery. These baroreceptors are sensitive to changes in blood pressure, particularly the stretch of the arterial wall. When blood pressure increases, the walls of the carotid sinus stretch more. This stretching is detected by the baroreceptors, which then send signals to the brain, specifically to the medulla oblongata, a region of the brainstem responsible for regulating cardiovascular functions.
In response to the increased stretch and the corresponding signal from the carotid baroreceptors, the brain initiates a reflex to lower blood pressure. One key component of this reflex is the activation of the parasympathetic nervous system. The parasympathetic nervous system, which is primarily mediated by the vagus nerve, plays a role in reducing heart rate and promoting relaxation of the heart. Increased vagus nerve stimulation leads to a slowing of the heart rate, a phenomenon known as bradycardia.
Additionally, there is a reduction in sympathetic nervous activity, which further contributes to the lowering of heart rate and vasodilation. This baroreceptor reflex is essential for maintaining homeostasis and ensuring that blood pressure does not rise too high, which could lead to damage of blood vessels and organs. The negative feedback loop established by the carotid baroreceptors helps to stabilize blood pressure by adjusting heart rate and vascular tone in response to changes in pressure. Thus, the increased stretch in carotid baroreceptors triggers a complex cascade that ultimately results in the increased vagus nerve stimulation to the heart.