學妹給的教科書參考解答:

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Heart rate is established by spontaneously depolarizing cells in the
sinoatrial node, and it is modulated by parasympathestic and sympathetic
neural activity at these pacemaker cells. These two functionally
antagonistic sources of innervation provide a powerful dual control
system characteristic of most autonomically controlled systems.


1. Basal sympathetic drive to the heart, like sympathetic outflow to the
vasculacutre, is known to emanante principally from the RVLM.
2. In the brainstem, parasympathetic preganglionic neurons that regulate
the heart are tonically active in vivo, largely refelecting sensory
afferent input from the cardiovascular amd respiratory systems.

Fundamental neuroscience, Zigmond, 1999, pp1055-1056.

教科書說法，僅供參考