Health Science I – Anatomy, Physiology, and Medical Conditions Practice Test

The circulatory system is the body’s transport network, built around the heart, blood vessels, and blood. The heart acts as a muscular pump that pushes blood into arteries, which carry it to tissues; veins return blood back to the heart; and capillaries are tiny vessels where exchange with cells occurs. Blood itself is the fluid that carries oxygen, nutrients, hormones, immune cells, and waste products to and from every part of the body. This combination—heart plus vessels plus blood—defines the circulatory system and supports circulation, tissue perfusion, and homeostasis. The digestive system handles nutrients, the nervous system coordinates signals, and the respiratory system handles gas exchange with the lungs—so they do not include all three components together.