Oxygen In Exhaled Air
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Why is there less oxygen in exhaled air than in inhaled air ?
The amount of oxygen in exhaled air is less than the amount of oxygen in inhaled air because of the process of respiration that occurs in the body.
Respiration is the process by which the body converts the oxygen we breathe in into energy. This process takes place in the cells of the body and is essential for the body's survival. The oxygen we breathe in is used to produce energy in the form of ATP (adenosine triphosphate), which is the energy currency of the cell.
When we inhale, we take in fresh air that contains a high concentration of oxygen. This oxygen-rich air then travels through the nose and down the trachea, into the lungs. In the lungs, the oxygen diffuses across the alveolar walls, and into the blood vessels. The oxygen-rich blood then travels through the circulatory system, delivering oxygen to all the cells of the body.
However, during the process of respiration, the oxygen that is delivered to the cells is not just used to produce energy. Some of the oxygen is also used to break down carbon dioxide, a waste product of the body's metabolism. This carbon dioxide is then exhaled out of the body.
As a result, the amount of oxygen in the exhaled air is less than the amount of oxygen in the inhaled air. The exact percentage of oxygen in exhaled air varies depending on the individual and their level of physical activity. At rest, the typical range is around 16% to 18% oxygen in exhaled air, while during exercise, this number can drop as low as 12%.
Another reason for the decrease in oxygen level in exhaled air is the process of ventilation perfusion mismatch, which occurs due to the uneven distribution of ventilation and perfusion (blood flow) in the lungs. When the alveoli in the lungs are not perfused, or supplied with blood flow, they are not able to extract oxygen from the inhaled air. This results in less oxygen being absorbed into the bloodstream and more being exhaled out of the body.
Additionally, there are also certain medical conditions that can affect the amount of oxygen in exhaled air. For example, conditions such as emphysema and chronic obstructive pulmonary disease (COPD) can cause damage to the lungs, making it harder for the body to extract oxygen from the inhaled air.
In conclusion, the amount of oxygen in exhaled air is less than the amount of oxygen in inhaled air because of the process of respiration that occurs in the body. The oxygen in inhaled air is used to produce energy and to break down carbon dioxide, which results in a decrease in the amount of oxygen in exhaled air. Additionally, factors such as ventilation perfusion mismatch and certain medical conditions can also affect the amount of oxygen in exhaled air.