Oxygen is one of the essential substances for the maintenance of human and other animal and plant life.
Oxygen enters the lungs through human breathing, and then passes through a thin layer of alveolar membrane to the blood, which binds to hemoglobin in the red blood cells in the blood. Hemoglobin seems to be a train that transports oxygen, along the orbit of human blood circulation. Oxygen is delivered to the tissues of various parts of the body. Oxygen then oxidizes with the nutrients ingested in various parts of the tissue. For example, under the catalysis of certain enzymes in the body, glucose and oxygen in the ingested food undergo a series of complex and moderate oxidation reactions. The heat released by this oxidation reaction can maintain the normal body temperature of the human body. Supply the energy of human life. The carbon dioxide produced by the reaction combines with the blood to return to the lungs through the vein and exhales out of the body. An adult consumes an average of 0.75 kg of oxygen per day and emits 0.9 kg of carbon dioxide. The average person stops breathing in a few minutes and life stops.
Some people think that only 21% of oxygen in the air, inhaling pure oxygen is more beneficial to the human body, which is wrong. Pure oxygen is harmful to the human body, and inhalation of pure oxygen can damage the epithelial layer of the lungs. Inhalation of 100% oxygen can cause lung oxygen poisoning in just a few days. Inhalation of high-pressure oxygen will cause serious damage to the lungs, mainly destroying the alveolar capillary barrier structure and impairing the function of the cilia. Neither the climbers, divers, pilots and patients use pure oxygen. 40% to 100% of oxygen is used in hospitals, and pure oxygen is only used for newborn asphyxia or shock patients, but not too long.