Consider statements about human physiology: 1. The sinoatrial node is the pacemaker of the heart. 2. The atrioventricular node delays the impulse before it reaches the ventricles. 3. The Purkinje fibers distribute the impulse to the ventricular muscle. Which are correct? MCQ with Answer and Explanation

The cardiac conduction system ensures coordinated heartbeats. The sinoatrial (SA) node generates the electrical impulse, acting as the natural pacemaker. The impulse reaches the atrioventricular (AV) node, which delays it slightly to allow the atria to fully contract and empty into the ventricles. The impulse then travels down the Bundle of His to the Purkinje fibers, which rapidly distribute it throughout the ventricular myocardium, causing ventricular contraction. All statements are correct.