After the Russian Revolution of 1917, Georgia declared independence in 1918, but the democratic Republic of Georgia, ruled by a social-democratic government, was invaded by the Red Army in 1921, a few days after it was recognized by European states.
And.. The Semilunar Valves prevent the back flow of the blood from the arteries to the ventricles. Explain what happens to tissues, such as the heart, or the brain, if oxygenated blood is not delivered in a timely manner. The tissue of the organ starts to die.
Arteries (along with smaller arterioles and microscopic capillaries) convey oxygen- and nutrient-rich blood to the body's tissues. In turn, veins bring nutrient-depleted blood back to the heart. Along the way, blood is routed through the kidneys and liver, as well, filtering waste products from the blood.