What are the main components of the circulatory system?

The main components of the circulatory system fundamentally consist of the heart, arteries, veins, and capillaries. The heart serves as the central pump to circulate blood throughout the body, while arteries carry oxygenated blood away from the heart to the tissues. Veins are responsible for returning deoxygenated blood back to the heart, and capillaries are the smallest blood vessels where the exchange of oxygen, carbon dioxide, nutrients, and waste occurs between the blood and surrounding tissues.

The first option mentions blood and lymphatic vessels, which while important, do not outline the primary structures that make up the circulatory system directly. The lymphatic system is a separate component that helps maintain fluid balance and is part of the immune system.

The lungs, trachea, and alveoli listed in the third option are components of the respiratory system, not the circulatory system. While they do interact with the circulatory system to facilitate gas exchange, they are not components of it.

Lastly, the gut or organ components mentioned in the fourth option (spleen, pancreas, and liver) play roles in digestion and metabolism but are not part of the circulatory system’s core structure.

Focusing on the most vital elements helps clarify that the key components