Which of the following statements is incorrect?
a. The firing of the SA node
stimulates both atria to contract almost simultaneously.
b. The signal to contract is
delayed at the AV node, allowing the ventricles to fill with blood.
c. Firing signals reach the
papillary muscles before the rest of the ventricular myocardium.
d. Ventricular contraction begins at
the AV valves and progresses downward toward the apex of the heart.
d. Ventricular contraction begins atthe AV valves and progresses downward toward the apex of the heart.