title: The sinus node as a servomechanism.
mesh_terms: D001693:Biological Transport, Active; D004594:Electrophysiology; D005246:Feedback; D006329:Heart Conduction System / Q000502:physiology; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D011984:Sensory Receptor Cells / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology; D012849:Sinoatrial Node / Q000166:cytology / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D012701:Serotonin