Question

Is there any particular reason why the walls of the auricles of the human heart is thinner than those of the ventricles?

Answer 1

Also, why does the valve separating the left auricle and ventricle thinner than the one separating the right auricle and ventricle?

Answer 2

Just stole this from wiki: "Ventricles have thicker walls than atria and must allow and withstand higher incoming and outgoing blood pressures"

http://en.wikipedia.org/wiki/Ventricle_%28heart%29

Answer 3

Well, the left ventricle must send blood to the hole body. For that reason, its blood pressure is increased, as so as its walls.