What are the main components of the cardiac system?

The main components of the cardiac system are indeed the heart, blood vessels, and blood. The heart serves as the central pump that circulates blood throughout the body, delivering oxygen and nutrients to tissues while also removing waste products. Blood vessels, which include arteries, veins, and capillaries, form an extensive network that facilitates this circulation. Arteries transport oxygen-rich blood away from the heart, while veins return oxygen-poor blood back to the heart. The blood itself is the fluid that carries oxygen, carbon dioxide, nutrients, and hormones, forming a vital part of this intricate system.

Other listed options include components that are not central to the cardiac system. For instance, lungs are crucial for respiration but are part of the respiratory system, not directly involved in the cardiac system’s primary functions. Options that mention only veins, capillaries, or digestive organs also fail to encompass the entirety of the cardiac system and its primary components. Understanding the full scope of the cardiac system highlights why the heart, blood vessels, and blood are fundamental to its structure and function.