Which statement about the cardiac cycle in mammals is true?
A) Only the ventricles contract in unison.
B) Only the atria contract in unison.
C) The atria contract in unison and the ventricles contract in unison.
D) Only the atrium and ventricle on the right side of the heart contract in unison.
E) Only the atrium and ventricle on the left side of the heart contract in unison.

Question

Quizplus · Accepted Answer

During the cardiac cycle in mammals, the atria contract first in unison, followed shortly by the ventricles contracting in unison. This is necessary for efficient blood flow through the heart and to the rest of the body. Therefore, statement C is the correct answer.

Which Statement About the Cardiac Cycle in Mammals Is True