Only Anatomy Majors Can Pass This Muscle Quiz

What is the hardest-working muscle in the body?

Retry Correct Incorrect The hardest-working muscle in the human body is the heart. This particular muscle works to pump around two ounces of blood every time your heart beats! It’s said that a heart can beat around three billion times during a lifetime.

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David Butow/Corbis via Getty Images

David Butow/Corbis via Getty Images

What is the hardest-working muscle in the body?

• Heart
• Tongue
• Brain
• Bicep