Which law relates wall tension, pressure, radius, and wall thickness in cylindrical vessels, and is applied to the heart?

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Multiple Choice

Which law relates wall tension, pressure, radius, and wall thickness in cylindrical vessels, and is applied to the heart?

Wall stress in a hollow chamber depends on the pressure inside and the size of the chamber, with thicker walls reducing the load. This is captured by Laplace's law for a thin-walled cylinder: the circumferential wall stress is sigma = P r / t, where P is internal pressure, r is radius, and t is wall thickness. The wall tension, the force the wall must bear per unit length, is T = sigma × t, which simplifies to T = P r for a thin wall. In other words, increasing internal pressure or enlarging the radius raises the wall stress, while increasing wall thickness lowers it. Applied to the heart, the left ventricle can be approximated as such a chamber. When pressure rises (as in hypertension) or the ventricle dilates (radius grows), the walls experience greater stress. Conversely, thickening the ventricular wall lowers wall stress. This relationship helps explain how changes in chamber size and wall thickness influence the heart’s mechanical load and oxygen demand.

Wall stress in a hollow chamber depends on the pressure inside and the size of the chamber, with thicker walls reducing the load. This is captured by Laplace's law for a thin-walled cylinder: the circumferential wall stress is sigma = P r / t, where P is internal pressure, r is radius, and t is wall thickness. The wall tension, the force the wall must bear per unit length, is T = sigma × t, which simplifies to T = P r for a thin wall. In other words, increasing internal pressure or enlarging the radius raises the wall stress, while increasing wall thickness lowers it.

Applied to the heart, the left ventricle can be approximated as such a chamber. When pressure rises (as in hypertension) or the ventricle dilates (radius grows), the walls experience greater stress. Conversely, thickening the ventricular wall lowers wall stress. This relationship helps explain how changes in chamber size and wall thickness influence the heart’s mechanical load and oxygen demand.

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