Baroreceptor is which type of feedback?
(A) Negative feedback (B) Positive feedback (C) Both negative and positive (D) Feed forward control
(A) Feedforward mechanism comes into action even before the change has occurred In feedback mechanisms, change occurs in controlled variable & the change is fedback to controller & the controller then takes the action. In negative feedback, the controller does the opposite, the change is negated or error is minimized. In positive feedback mechanism, controller does the same in direction of error & error is amplified. If the BP is increased, baroreceptor acts in a way as to decrease it or vice- versa. Increased pressure in blood vessels containing baroreceptor causes increased impulse firing. Baroreceptor signal enters the nucleus tractus solitarius, inhibit the vasoconstrictor center of the medulla, excite the vagal center. The net effects are inhibition of sympathetic activity, which causes vasodilation of veins & aerioles, decreased hea rate & strength of hea contraction. Baroreceptor maintain aerial pressure at a relatively constant level during changes in body posture and other daily activites.