The total length of human blood vessels is about 96,000 kilometers. The blood in the blood vessels mainly serves the functions of transporting oxygen, nutrients, and regulating body fluids. The blood circulation in the human body is mainly divided into: body circulation and pulmonary circulation. 1. Physical circulation: Physical circulation begins in the left ventricle. After the blood is pumped out of the left ventricle, it passes through all levels of arterial branches and is pumped into various organs of the body. After the arterial blood, which is rich in oxygen and nutrients, reaches the capillaries, the oxygen and nutrients in the blood enter the cells and tissues, and the tissues can discharge carbon dioxide and other metabolic products. From there, arterial blood becomes venous blood, which flows back into the right atrium. 2. Pulmonary circulation: The pulmonary circulation begins in the right ventricle. The right ventricle pumps venous blood through the pulmonary artery and into the capillaries of the lungs, where carbon dioxide is eliminated and oxygen enters the bloodstream, turning venous blood into arterial blood, which then flows back to the left atrium via the pulmonary vein. The blood from the left atrium is pumped into the left ventricle and again via the body circulation. If you feel unwell, it is advisable to go to the hospital for examination.