Arterial blood comes through a large circle of blood circulation to organs and tissues, where it gives off oxygen and takes carbon dioxide. Due to the fact that there is much less oxygen in the intercellular fluid and in the cells than in the blood brought through the vessels of the systemic circulation, hemoglobin gives up oxygen. It enters the tissue fluid surrounding the blood capillaries, and then enters the cells, where it is consumed in the oxidation of organic substances. As a result of cellular respiration, carbon dioxide is formed. It passes from the cells first into the intercellular fluid, and then through the single-layer walls of the capillaries enters the blood.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.