Final answer:
The circulatory system is the organ system that transports nutrients, metabolic wastes, gases, and defense cells throughout the body. It operates through an extensive network of blood vessels, carrying oxygen and nutrients to cells and removing carbon dioxide and wastes.
Step-by-step explanation:
The organ system responsible for transporting nutrients, metabolic wastes, gases, and defense cells is the circulatory system. This system is similar to highway networks because it transports oxygen, nutrients, and hormones to the body cells while also moving wastes and carbon dioxide away from the cells. In the human body, the circulatory system consists of a complex network of blood vessels that extend to all parts of the body to provide essential substances needed for energy and cell function, as well as to remove waste products generated from respiration and other metabolic processes.
The transportation function of the circulatory system is critical. Nutrients absorbed from the digestive tract are processed in the liver and then released back into the bloodstream to reach body cells. Oxygen inhaled from the air diffuses into the bloodstream and is carried to the rest of the body. Meanwhile, hormones released from endocrine glands enter the bloodstream to reach target cells. Additionally, the circulatory system collects cellular wastes and transports them to organs for removal, such as carrying carbon dioxide to the lungs for exhalation and waste products to the kidneys and liver for excretion.