Final answer:
The circulatory system consists of the heart, blood, and blood vessels, including arteries, veins, and capillaries. The heart pumps blood through the coronary, pulmonary, and systemic circulations to deliver oxygen and nutrients to the body and to remove waste products.
Step-by-step explanation:
The circulatory system, also known as the cardiovascular system, comprises several vital organs and structures that work together to supply the body with nutrients, oxygen, and other essential substances. The primary components of this system include the heart, blood vessels (arteries, veins, and capillaries), and blood. The heart is a muscular organ that pumps blood throughout the body, and it has four chambers: two upper atria and two lower ventricles, each with valves to ensure blood flows in one direction. The three main divisions of the circulatory system that the heart pumps blood through are the coronary circulation (serving the heart itself), the pulmonary circulation (between the heart and lungs), and the systemic circulation (to the rest of the body). Apart from the heart, the blood vessels are crucial in transporting blood; arteries carry blood away from the heart, veins return blood to the heart, and capillaries facilitate the exchange of substances between blood and tissues. Oxygenated blood is carried to the cells and carbon dioxide is taken away, maintaining homeostasis throughout the body. The cardiovascular system's primary function is thus the transportation of vital materials, making it indispensable for survival.