What is the primary function of cardiac muscle?

• A. To control voluntary movements
• B. To contract and pump blood through the heart
• C. To store calcium for muscle contraction
• D. To generate heat

Answer: (B)

The main idea here is that cardiac muscle is specialized to pump blood. It contracts in a coordinated, rhythmic way so the heart can move blood through its chambers and into the circulation, supplying oxygen and nutrients to the body. This tissue is involuntary, meaning you don’t consciously control its contractions, and it’s built for continuous, durable performance. Intercalated discs connect heart muscle cells to allow rapid, synchronized beating, while the heart’s intrinsic conduction system sets the pace and rhythm, with autonomic nerves modulating rate and force as needed.

Calcium plays a key role in triggering contraction, but storing calcium for contraction isn’t the primary function of cardiac muscle. Generating heat is a general result of metabolic activity in all tissues, not the specific job of the heart.