How Do the Walls of the Atria & Ventricles Differ?

Function and Form

The heart consists of four chambers: the upper chambers on the left and right is the atria and the lower left and right chambers are known as the ventricles.

The atria function to receive blood that enters the heart, then passing the blood along to the ventricles, which then send blood to the lungs and other body parts. Because each serves a different function, the composition of the atria and ventricle walls may be different.

The Ventricles

The walls of the ventricles are thick and muscled because they must be strong enough to push blood away from the heart and through the body. The muscular wall that lines the ventricle is called the interventricle wall.

The Atria

How Do the Walls of the Atria & Ventricles Differ?

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In contrast to the thick, muscular walls of the ventricles, the atria are thinner, and are lined with what are called pestinate muscles. These muscles resemble lattice and line the interior wall. The atria's thinner walls when compared to the ventricles are directly related to its function: blood flows into the atria, and very little force is needed (and therefore less heart muscle in the walls) to propel the blood to the atria.