Kaplan Nursing Entrance Practice Exam

What part does the cardiac muscle play in the heart?

1. It facilitates gas exchange

2. It transmits nervous impulses for contraction

3. It separates the right and left chambers

4. It creates a barrier against infection

The correct answer is: It transmits nervous impulses for contraction

The role of cardiac muscle in the heart is primarily to enable the contraction and relaxation necessary for pumping blood throughout the body. This specialized muscle tissue is responsible for the rhythmic contractions of the heart, which are essential for maintaining circulation. The cardiac muscle fibers are interconnected and can transmit electrical impulses, allowing for coordinated contractions that ensure effective blood flow. This transmission of impulses is critical because it allows different parts of the heart to beat in a synchronized manner, facilitating efficient pumping. The unique properties of cardiac muscle, including automaticity and rhythmicity, contribute to its ability to respond to the electrical signals generated by the heart's conduction system. In contrast, the other options do not accurately reflect the primary function of cardiac muscle. Gas exchange is a function of the lungs and alveoli, while separating chambers refers to the role of septa within the heart. Finally, creating a barrier against infection is associated with the body's overall immune response, not a specific function of cardiac muscle. Therefore, the role of cardiac muscle is crucial in enabling the heart to perform its primary function of blood circulation through contraction.