The cardiovascular system is a vital transportation system in the body. It comprises the heart and blood vessels and facilitates the exchange of gases, nutrients, and waste products.

Heart

The heart is the central pump of the cardiovascular system that circulates blood throughout the body. It comprises two atria receiving the blood and two ventricles pumping blood out of the heart. Their rhythmic contractions, called heartbeats, ensure that blood flow remains continuous.

Blood Vessels

Blood vessels are like pipelines, carrying blood to all body parts. There are three types: arteries, veins, and capillaries.

• Arteries: Arteries are muscular, elastic blood vessels that transport oxygenated blood from the heart to different tissues and organs, withstanding the high pressure generated by the heart's pumping action.
• Veins: Veins have thinner walls than arteries but contain valves to prevent the backward flow of deoxygenated blood back to the heart, acting as the return routes of the cardiovascular system.
• Capillaries: Capillaries form a network throughout the body, allowing for nutrient and gas exchange with surrounding cells. Oxygen and nutrients diffuse into the tissues while carbon dioxide and other waste products are removed.

Double Circulation

Double circulation involves two loops: pulmonary circulation and systemic circulation.

• Pulmonary Circulation: This loop carries deoxygenated blood from the heart to the lungs. The heart pumps the blood to the lungs, picking up oxygen and releasing carbon dioxide.
• Systemic Circulation: This loop transports oxygenated blood from the heart to the rest of the body's tissues and organs. The tissues utilize the oxygen and nutrients, and the deoxygenated blood is collected and sent back to the heart through veins.