Which aspect of arterial physiology is most closely associated with arterial storage in the Windkessel model?

• A. Compliance.
• B. Resistance.
• C. Inertia.
• D. Viscosity.

Answer: (A)

Arterial storage in the Windkessel model comes from how easily the arteries expand to take in and hold blood, which is called compliance. The Windkessel uses a capacitor-like idea: when the heart ejects blood, the elastic walls of the arteries stretch and store volume as elastic energy. That stored energy is then released during diastole to keep blood flowing even when the heart isn’t ejecting as strongly. This reservoir function smooths both pressure and flow over the cardiac cycle.

Resistance, by contrast, represents how much the downstream vessels oppose flow and dissipate energy; inertia reflects the blood’s mass trying to keep moving; viscosity concerns internal friction within the blood. The storage behavior specifically hinges on the arteries’ ability to stretch and hold volume, i.e., compliance.