The cardiovascular system consists of which components?

• A. Heart, Blood Vessels, Blood
• B. Lungs, Heart, Nerves
• C. Brain, Heart, Blood
• D. Heart, Lungs, Blood

Answer: (A)

The cardiovascular system is built from three parts working together: the heart, the blood vessels, and the blood. The heart provides the pumping action that moves blood through arteries, capillaries, and veins. Blood vessels form the network that delivers and returns blood to every tissue, with arteries carrying blood away from the heart, veins returning it, and capillaries enabling exchange with tissues. Blood is the fluid that transports oxygen, carbon dioxide, nutrients, waste products, hormones, and immune cells throughout the body. The lungs and brain, while essential to breathing and nervous control, belong to other systems—respiratory and nervous—so they aren’t counted as components of the cardiovascular system. That’s why heart, blood vessels, and blood best describe the cardiovascular system.