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.
We need a transport system to deliver oxygen, nutrients and other substances to all our body cells, and take away waste products from them. The oxygenated blood (high in oxygen, red in color) comes to the heart from the lungs in the pulmonary vein; the heart pumps it to the aorta (an artery) to the rest of the body.