A. Nodal tissue: The heart is myogenic, meaning the impulse for the heartbeat is generated by specialized nodal tissue (like the SA node and AV node) without external nerve stimulation.

B. Special neural centre in the medulla oblongata: While the heart is auto-excitable, its rate can be moderated by the Autonomic Nervous System (ANS). A neural center in the medulla oblongata can increase or decrease cardiac output through sympathetic and parasympathetic nerves.

C. Adrenal medullary hormones: Hormones like epinephrine (adrenaline) and norepinephrine from the adrenal medulla can significantly increase the heart rate and the strength of ventricular contraction.

D. Adrenal cortical hormones: These hormones (like cortisol or aldosterone) primarily regulate metabolism and mineral balance; they do not play a direct role in the regular regulation of cardiac activities.