Which of the following nucleus has cardio inhibitory function?
(A) Nucleus Ambiguus (B) Nucleus Tractus Solitarius (C) Rostral Ventrolateral Medulla (D) Dorsal motor nucleus of vagus
(A) Ans. A. Nucleus AmbiguusThe nucleus ambiguus in its "external formation" contains cholinergic preganglionic parasympathetic neurons for the hea.These neurons are cardioinhibitory.This cardioinhibitory effect is one of the means by which quick changes in blood pressure are achieved by the central nervous system (the primary means being changes in sympathetic nervous system activity, which constricts aerioles and makes the hea pump faster and harder).