kiertojärjestelmällä

Kiertojärjestelmällä, often translated as "circulatory system," refers to the biological system responsible for transporting nutrients, oxygen, hormones, and other essential substances throughout an organism's body. It also plays a crucial role in removing waste products like carbon dioxide. In vertebrates, the circulatory system is a closed loop, meaning the blood is always contained within a network of blood vessels. The central component of this system is the heart, a muscular organ that pumps blood.

The circulatory system consists of three main parts: the heart, blood vessels, and blood. The heart acts as the pump, generating the pressure needed to move blood. Blood vessels are tubes through which blood flows. Arteries carry blood away from the heart, typically oxygenated blood, although the pulmonary artery is an exception. Veins carry blood back to the heart, usually deoxygenated blood, with the pulmonary veins being the exception. Capillaries are the smallest blood vessels, forming a vast network that connects arteries and veins, and are the site where the exchange of gases, nutrients, and waste occurs between the blood and the body's tissues. Blood itself is a fluid connective tissue composed of plasma, red blood cells, white blood cells, and platelets. Red blood cells carry oxygen, white blood cells are involved in immunity, and platelets help in blood clotting. The efficient functioning of the kiertojärjestelmällä is vital for sustaining life.