What are two primary roles of long bones?

What are two primary roles of long bones?

• A. Movement and blood production
• B. Support and protection
• C. Heat generation
• D. Blood circulation

Answer: (A)

Long bones have two key jobs: enabling movement and making blood cells. They act as levers for muscles—when muscles contract, the forces transmitted through these bones create movement around joints, allowing walking, running, lifting, and other motions. Inside the hollow part of long bones is bone marrow, where blood cells are produced, supporting oxygen transport, immunity, and clotting. Heat generation isn’t a primary function of bones, as it comes mainly from muscle activity and metabolism. Blood circulation is driven by the heart and blood vessels, not by the bones themselves.

Long bones have two key jobs: enabling movement and making blood cells. They act as levers for muscles—when muscles contract, the forces transmitted through these bones create movement around joints, allowing walking, running, lifting, and other motions. Inside the hollow part of long bones is bone marrow, where blood cells are produced, supporting oxygen transport, immunity, and clotting.

Heat generation isn’t a primary function of bones, as it comes mainly from muscle activity and metabolism. Blood circulation is driven by the heart and blood vessels, not by the bones themselves.