Cardiac muscle cells are best described as:

Cardiac muscle cells are best described as:

• A. Fast, voluntary contractions similar to skeletal muscle
• B. Strong, quick contractions that occur involuntarily
• C. Non-contractile
• D. Slow, sustained contractions

Answer: (B)

Cardiac muscle is built to pump blood automatically and rhythmically, so its contractions are involuntary and coordinated. The heart’s cells are connected by intercalated discs, which lets electrical signals sweep across the tissue quickly and beat as a single unit. This setup produces strong contractions needed to move blood, and while the autonomic nervous system can adjust the rate and force, you don’t consciously control it. Descriptions that imply voluntary control, that the muscle doesn’t contract, or that its contractions are slow and sustained don’t fit how the heart actually works.

Cardiac muscle is built to pump blood automatically and rhythmically, so its contractions are involuntary and coordinated. The heart’s cells are connected by intercalated discs, which lets electrical signals sweep across the tissue quickly and beat as a single unit. This setup produces strong contractions needed to move blood, and while the autonomic nervous system can adjust the rate and force, you don’t consciously control it. Descriptions that imply voluntary control, that the muscle doesn’t contract, or that its contractions are slow and sustained don’t fit how the heart actually works.