What is the primary function of the circulatory system?

What is the primary function of the circulatory system?

• A. To exchange oxygen and carbon dioxide with the atmosphere.
• B. To transport nutrients, gases, hormones, and wastes around the body.
• C. To regulate body temperature and moisture.
• D. To produce hormones.

Answer: (B)

The circulatory system primarily functions to move substances throughout the body. Blood acts as a transport highway, delivering nutrients absorbed from the digestive system to every cell, carrying oxygen from the lungs to tissues, and removing carbon dioxide and other wastes to excretory sites. It also shuttles hormones from glands to their target organs, helping coordinate body processes. While blood flow can distribute heat to aid temperature regulation, the main role is transportation of these substances. Gas exchange with the environment happens in the lungs as part of respiration, not directly through the circulatory system, and hormones are produced by glands, not by the circulatory system itself.

The circulatory system primarily functions to move substances throughout the body. Blood acts as a transport highway, delivering nutrients absorbed from the digestive system to every cell, carrying oxygen from the lungs to tissues, and removing carbon dioxide and other wastes to excretory sites. It also shuttles hormones from glands to their target organs, helping coordinate body processes. While blood flow can distribute heat to aid temperature regulation, the main role is transportation of these substances.

Gas exchange with the environment happens in the lungs as part of respiration, not directly through the circulatory system, and hormones are produced by glands, not by the circulatory system itself.