Blood Flow Explained: Pressure, Vessels, and Tissue Supply

From the heart to tissues and back again

Blood moves through a closed network connecting the heart, lungs, and tissues. The lungs add oxygen and remove carbon dioxide. The left ventricle pumps oxygen-rich blood into the aorta and systemic arteries, and veins return blood to the right side of the heart.^[1][2]

Arteries are defined by carrying blood away from the heart, and veins by carrying blood toward it. At capillary networks, oxygen and other substances can exchange over short distances between blood and tissues.^[1][2]

Pressure, resistance, and flow are related but different

In simplified physiology, flow depends on the pressure difference across a vascular bed and resistance within it. A blood-pressure reading is therefore related to, but not identical with, blood flow or tissue oxygen delivery.^[2]

Arterioles help regulate resistance and distribute blood flow into local capillary beds. Perfusion describes blood moving through a tissue’s vascular network, where exchange can occur.^[2][3]

CLAIM 1 — STRONG

EECP augments circulation during the cardiac cycle

Enhanced external counterpulsation (EECP), also called external counterpulsation (ECP), is a noninvasive, ECG-timed cuff therapy.

EECP uses lower-body cuffs that inflate sequentially during diastole and deflate before systole. Direct measurements and clinical literature describe increased diastolic pressure and coronary flow, increased venous return, and systolic unloading.^[4]

Randomized studies in chronic coronary disease populations have also reported changes in endothelial-function measures and coronary collateral-flow index after counterpulsation. These findings establish a circulation mechanism in the studied populations; they are not a condition-specific clinical outcome for every reader.^[5][6]