Question

which of the following statements is not correct?
the walls of the ventricles are thicker because the ventricles pump blood under higher pressure over greater distances.
the walls of the atria are thicker because the atria receive blood under pressure.
the wall of the right ventricle is thinner than that of the left ventricle because the right side of the heart pumps blood a shorter distance at lower pressure.
although the right side of the heart has a smaller workload, the right and left ventricle simultaneously eject the same amount of blood.
all of these choices are correct.

Explanation:

The atria receive blood passively and do not need thick walls to handle pressure - they mainly act as conduits to fill the ventricles. Ventricles, on the other hand, pump blood out of the heart under high pressure, so their walls are thicker. The left ventricle pumps blood to the entire body, so it has a thicker wall compared to the right ventricle which pumps blood to the lungs. Also, the right and left ventricles eject the same amount of blood per beat.

Answer:

The walls of the atria are thicker because the atria receive blood under pressure.