Bainbridge reflex is due to:-
Bainbridge reflex: Increase in atrial pressure causes increase in hea rate by nervous reflex called Bainbridge reflex 40 - 60 % increase in rate is due to this reflex while 15% increase is by direct effect of increased atrial volume to stretch sinus node. Stretch receptors of atria that elicit Bainbridge reflex transmit their afferent signals through vagus nerve to medulla of brain. These efferent signals are transmitted back through vagal & sympathetic nerves to increase H.R & strength of hea contraction. This reflex helps prevent damming of blood in atria, veins & pulmonary circulation Best known nerve mechanisms for aerial pressure control Reflex is initiated by stretch receptors called baroreceptors /pressoreceptors located at specific points in walls of several large systemic aeries A rise in aerial pressure stretches baroreceptor & causes them to transmit signals into CNS. "feedback" signals are then sent back through autonomic nervous system to circulation to reduce aerial pressure downward towards the normal level
Stretching of atria
Baroreceptor reflex
Decreased venous return
Increased ventricular activity
NEET 2019