Passive Mechanical Wall Composition (Wall Elasticity, Systemic, Endothelium,Elastic, Compliance) Pressure Muscle,Nerves Fibrous Vessel Lumen Size Nerve Vasoactive Substances Active Center Nerve,Hormous,Endothelium External StimuliVasoactive Substances Nerve, Hormous, Endothelium Wall Composition Endothelium, Elastic, Muscle, Nerves Fibrous Vessel Lumen Size Systemic Pressure Nerve Center Passive Mechanical (Wall Elasticity, Compliance) External Stimuli Active