Question

Which of the following statements regarding the circulatory system is correct?

a. the sinoatrial node is present in the top section of the right atrium
b. all veins carry deoxygenated blood back to the heart
c. the heart's "lub-dub" sound is caused by the electrical impulse generation
d. the heart's atria have thicker walls than the ventricles

Answer 1

The sinoatrial node is present in the top section of the right atrium.

Step-by-step explanation:

The correct statement about the circulatory system is a. the sinoatrial node is present in the top section of the right atrium. The sinoatrial (SA) node is the natural pacemaker of the heart and is located in the top section of the right atrium. It generates electrical impulses that control the heart's rhythm.