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

What type of muscle is the heart made of?

1. Skeletal muscle

2. Cardiac muscle

3. Smooth muscle

4. Voluntary muscle

The correct answer is: Cardiac muscle

The heart is made of cardiac muscle, which is a unique type of muscle tissue specifically adapted for the continuous, rhythmic contractions needed to pump blood throughout the body. Cardiac muscle is striated like skeletal muscle but is involuntary and can contract without conscious control. This muscle type has cells that are interconnected by intercalated discs, allowing for efficient communication and synchronized contractions, which is essential for maintaining a steady heartbeat. Skeletal muscle, while also striated and capable of strong contractions, is under voluntary control and is primarily attached to bones to facilitate movement. Smooth muscle, which is found in various internal organs and blood vessels, is not striated and also involuntarily controlled. Voluntary muscle refers to muscles that are consciously controlled, which would exclude cardiac muscle since it operates automatically to maintain the heart’s rhythm. These distinctions highlight why cardiac muscle is the correct answer, as it is especially suited for the heart's function.