leviämiselimistöä

Leviämiselimistöä, also known as the circulatory system or cardiovascular system, is a network of organs and vessels that transports blood throughout the body. This essential system is comprised of the heart, blood vessels (arteries, veins, and capillaries), and blood. The primary function of the circulatory system is to deliver oxygen, nutrients, hormones, and other vital substances to cells and tissues, while simultaneously removing carbon dioxide and metabolic waste products.

The heart, a muscular organ, acts as the central pump, rhythmically contracting to propel blood through the vessels. Arteries carry oxygenated blood away from the heart to the rest of the body, branching into smaller arterioles and eventually into tiny capillaries. Capillaries are the sites where the exchange of gases, nutrients, and waste occurs between the blood and the body's cells. Deoxygenated blood is then collected by venules, which merge into larger veins, returning the blood to the heart. This continuous circulation ensures that all parts of the body receive the necessary resources for survival and function. The circulatory system is vital for maintaining homeostasis, regulating body temperature, and defending against pathogens.