Kiertoelimistön

Kiertoelimistö, also known as the circulatory system, is a network of organs and vessels that transport blood throughout the body. This system is vital for sustaining life, as it delivers oxygen and nutrients to cells and removes carbon dioxide and other waste products. The primary components of the circulatory system include the heart, blood vessels, and blood.

The heart is a muscular organ located in the chest that acts as a pump. It rhythmically contracts and relaxes, propelling blood through the arteries and veins. Blood travels in two main circuits: the pulmonary circulation and the systemic circulation. Pulmonary circulation carries blood between the heart and the lungs, where blood picks up oxygen and releases carbon dioxide. Systemic circulation distributes oxygenated blood from the heart to the rest of the body and returns deoxygenated blood to the heart.

Blood vessels are tubes that form the pathways for blood flow. Arteries carry blood away from the heart, branching into smaller arterioles and then capillaries, which are tiny vessels where the exchange of gases and nutrients occurs. From the capillaries, blood flows into venules and then larger veins, which return blood to the heart.

Blood itself is a fluid connective tissue composed of plasma, red blood cells, white blood cells, and platelets. Red blood cells are responsible for oxygen transport, white blood cells are part of the immune system, and platelets aid in blood clotting. Plasma is the liquid component that carries these cells, along with nutrients, hormones, and waste products. The continuous movement of blood through the kiertoelimistö ensures that all parts of the body receive the necessary substances to function and remain healthy.