Regulation of Cardiac Activity

The heart is capable of regulating its own beating without depending on outside signals, but that intrinsic rhythm can still be adjusted by the nervous system and by hormones.

Intrinsic (myogenic) control

The normal activity of the heart is auto-regulated by specialised muscle called nodal tissue. Because the beat originates from within the heart's own muscle rather than from nerves, the heart is described as myogenic.

Neural regulation

A special neural centre in the medulla oblongata can moderate cardiac function, acting through the autonomic nervous system (ANS), which has two opposing branches:

• Sympathetic nerves — signals through these can increase the heart rate, the strength of ventricular contraction and, as a result, the cardiac output. …