Fig. 1.6 Autonomic control
Autonomic tone is controlled by the cardiovascular centre in the medulla of the brain. Heart rate and contractility are dependent on the balance between sympathetic and parasympathetic output. Input comes from a number of sources: changes in blood pressure are detected in the aortic arch, carotid bodies and ventricles, and volume changes are detected in the atria. Additional information comes from other centres in the brain.