Which of the following statements about cardiac muscle and skeletal muscle is true?

• A. They are both striated.
• B. They are both voluntary.
• C. They are both composed of long muscle fibers.
• D. They both have intercalated discs.

Answer: (A)

Verified step by step guidance

1. Begin by understanding the basic characteristics of cardiac and skeletal muscles. Cardiac muscle is found in the heart, while skeletal muscle is attached to bones and helps in movement.
2. Recognize that both cardiac and skeletal muscles are striated, meaning they have a banded appearance due to the arrangement of actin and myosin filaments.
3. Consider the control mechanism of these muscles: Skeletal muscle is voluntary, meaning it is under conscious control, whereas cardiac muscle is involuntary, operating without conscious control.
4. Examine the structural differences: Skeletal muscle fibers are long and cylindrical, while cardiac muscle fibers are shorter and branched, connected by intercalated discs.
5. Understand the function of intercalated discs: These are unique to cardiac muscle and facilitate synchronized contraction by allowing electrical impulses to pass quickly between cells.