Which structures coordinate contraction in cardiac muscle cells within the electrical conduction system of the heart?

• A. Chordae tendineae
• B. Coronary arteries
• C. Sinoatrial node
• D. Atrioventricular valves

Answer: (C)

Verified step by step guidance

1. Understand the role of the electrical conduction system in the heart, which is responsible for initiating and coordinating the contraction of cardiac muscle cells.
2. Identify the key components of the heart's electrical conduction system, including the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibers.
3. Recognize that the sinoatrial node, often referred to as the heart's natural pacemaker, is responsible for generating electrical impulses that initiate the contraction of the heart muscle.
4. Learn how the electrical impulse from the sinoatrial node travels through the atria, causing them to contract, and then reaches the atrioventricular node, which delays the impulse before it passes to the ventricles.
5. Differentiate between the sinoatrial node and other structures mentioned, such as chordae tendineae, coronary arteries, and atrioventricular valves, which have different functions unrelated to the coordination of cardiac muscle contraction.