What two organs are primarily involved in the cardiovascular system?

The cardiovascular system's primary organs are the heart and lungs. The heart serves as the central pump of the system, responsible for circulating blood throughout the body, delivering oxygen and nutrients to tissues, and removing waste products. It operates in tandem with the lungs, which are crucial for oxygenating the blood. As blood travels from the heart to the lungs, it releases carbon dioxide and picks up oxygen through the process of respiration. This relationship is vital for maintaining the body's overall health and functionality.

The other options are not directly involved in the cardiovascular system's primary functions. The kidneys and liver are part of the excretory and metabolic systems, while the brain plays a role in regulating bodily functions but is not directly involved in the transport of blood. The spleen and pancreas contribute to other systems, with the spleen involved in immune responses and blood filtration, and the pancreas related primarily to digestion and blood sugar regulation.