Baroreceptors are sensory receptors located in the walls of blood vessels and the heart. They respond to stretch and pressure changes within the vessels, providing the body with information about the volume and pressure of circulating blood. This information is then used by the body to regulate heart rate, blood pressure, and other physiological parameters (Pagani et al., 1988; Mitchell et al., 2019).
Baroreceptors are sensitive to both short-term and long-term changes in blood pressure. When blood pressure increases, the baroreceptors trigger a reflex that causes the heart rate to decrease and the vasculature to dilate, resulting in a decrease in total peripheral resistance (Pagani et al., 1988). Conversely, when blood pressure decreases, the baroreceptors trigger a reflex that causes the heart rate to increase and vasculature to constrict, resulting in an increase in total peripheral resistance (Pagani et al., 1988).
The baroreflex system is responsible for maintaining homeostasis and protecting the body from the effects of excessive increases or decreases in blood pressure. For example, if blood pressure were to drop too low, the baroreflex system would respond by increasing heart rate and constricting the vessels, resulting in an increase in total peripheral resistance and an increase in blood pressure (Mitchell et al., 2019). Conversely, if blood pressure were to rise too high, the baroreflex system would respond by decreasing heart rate and dilating the vessels, resulting in a decrease in total peripheral resistance and a decrease in blood pressure (Mitchell et al., 2019).
Although the baroreflex system is essential for maintaining homeostasis, it is not the only factor that affects blood pressure. Other factors such as hormones, diet, and exercise can also affect blood pressure (Pagani et al., 1988). For example, the hormone adrenaline can cause a sudden increase in blood pressure, while exercise can cause a decrease in blood pressure (Pagani et al., 1988).
In conclusion, baroreceptors are sensory receptors located in the walls of blood vessels and the heart that respond to stretch and pressure changes within the vessels. They enable the body to maintain homeostasis by triggering reflexes that adjust heart rate and peripheral vascular resistance in response to changes in blood pressure. However, they are not the sole factor that affects blood pressure, as other factors such as hormones, diet, and exercise can also affect blood pressure.
References
Mitchell, J. H., Low, P. A., & Marshall, J. M. (2019). Cardiovascular physiology: Mosby’s Physiology Monograph Series. Elsevier.
Pagani, M., Lombardi, F., Guzzetti, S., Rimoldi, O., Furlan, R., Pizzinelli, P., & Malliani, A. (1988). Power spectral analysis of heart rate and arterial pressure variabilities as a marker of sympatho-vagal interaction in man and conscious dog. Circulation, 77(4), 1103-1118.