Regulation of coronary circulation is

Coronary circulation is regulated by chemical factors, physical factors, hormonal factors, neural factors, and autoregulation. Products of metabolism like CO2, H+, K+, lactic acid, adenosine, bradykinin, prostaglandin, adenine nucleotide etc produces vasodilation. Physical factors are BP, Peripheral resistance, Hea rate and phases of the cardiac cycle. Thyroxine, catecholamines, Ach increases coronary blood flow whereas angiotensin decreases.Neural regulation by sympathetic and parasympathetic supply.Autoregulation refers to the ability of an organ to maintain a relatively constant blood flow over a wide range of aerial blood pressure. Ref: Textbook of medical physiology by N Geetha, 2nd edition, page no. 200,201