Which organ is supplied with blood by the coronary artery?

All the components of the conducting system can generate an action potential for the contraction of heart muscle,but the Sinoatrial node acts as the pacemaker because

Which of the following statements about the human heart is correct?

What are Purkinje fibers?

What are the values of stroke volume and cardiac output under normal conditions?
Stroke Volume $\quad$ Cardiac Output

Muscles of the heart are