OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which type of muscle is found in the heart?

1. Skeletal muscle

2. Cardiac muscle

3. Smooth muscle

4. Involuntary muscle

The correct answer is: Cardiac muscle

The type of muscle found in the heart is cardiac muscle. This muscle is unique in its structure and function, specifically designed to continuously pump blood throughout the body. Cardiac muscle fibers are striated like skeletal muscle, but they are arranged in a network that allows for synchronized contraction, essential for effective heartbeats. Additionally, cardiac muscle is involuntary, meaning it operates without conscious control, which is crucial since the heart must beat continuously to maintain blood circulation and support life. Skeletal muscle, while striated and under voluntary control, is primarily involved in the movement of bones and is not found in the heart. Smooth muscle, which is found in the walls of hollow organs like intestines and blood vessels, is non-striated and also involuntary, but it serves different functions compared to cardiac muscle. The term "involuntary muscle" encompasses both cardiac and smooth muscle types, but it does not specifically identify the unique properties of cardiac muscle that make it essential for heart function. Thus, cardiac muscle is specifically the correct answer.