The right and left coronary arteries arise at the root of the aorta behind the cusps of the aortic valve. The heart influences its blood supply by the squeezing effect of the contracting myocardium on the blood vessels. The major factor in the regulation of coronary blood flow is a change in arteriolar resistance engendered by changes in metabolic activity.
Neural control is more important than local control for skin vessels.
Skeletal Muscle Circulation Contractile activity and type of muscle determines blood flow. Skeletal muscle vascular bed plays imprtant role in baroreflex and blood pressure regulation. Half of the aortic pressure is lost immediately distal to the major cerebral arteries. Since the cerebral circulation seems to be devoid of precappilary sphincters, the regulation of resistance across the vascular bed lies mainly in the arterial and arteriolar segments. Endothelial tight junctions are uninterrupted and form an effective obstacle to vascular diffusion.