Is blood pressure negative or positive feedback?

Blood pressure regulation involves both negative and positive feedback mechanisms.

Negative feedback: The baroreflex mechanism operates as a negative feedback loop. When blood pressure increases, the baroreceptors in the carotid sinus and aortic arch sense the rise and send signals to the brainstem. The brainstem then activates the parasympathetic nervous system, which slows down the heart rate and dilates blood vessels. This leads to a decrease in blood pressure.

Positive feedback: In certain situations, such as during childbirth or fainting, positive feedback mechanisms may come into play. For instance, during labor, the release of oxytocin stimulates uterine contractions. As the contractions become more intense and frequent, they can cause an increase in blood pressure. This elevation in blood pressure further stimulates the release of oxytocin, leading to even stronger contractions. This positive feedback loop contributes to the progression of labor.

Overall, blood pressure regulation involves a complex interplay of both negative and positive feedback mechanisms to maintain blood pressure within a narrow range necessary for proper physiological functioning.