Which components are part of the circulatory system?

The components that are part of the circulatory system include the heart, blood vessels, and blood. The heart acts as the central pump of the circulatory system, propelling blood throughout the body. Blood vessels—including arteries, veins, and capillaries—are the pathways that carry blood to and from various tissues and organs. Blood itself is the fluid that transports oxygen, nutrients, hormones, and waste products throughout the body.

Understanding the roles of these components is essential to grasp how the circulatory system functions as a vital network that supports homeostasis and overall health. The other options provided include components from different body systems, such as the brain, lungs, liver, and muscles, which do not belong to the circulatory system and have different functions related to the nervous system, respiratory system, and musculoskeletal system, respectively.