What is atmospheric pressure?|Effects of high pressure on human body|
The atmosphere exerts pressure on the human body. This is known as atmospheric pressure. At sea level, it is 760 mm. of mercury which is called 1 (one) atmospheric pressure.
Table of contents:
| 1. | Definition |
| 2. | Composition of air |
| 3. | The partial pressure of gases |
| 4. | How to calculate the partial pressure |
| 5. | The relevant law of gases |
| 6. | Important effects of high pressure |
The atmospheric pressure decreases with an increase in height and increases with an increase in depth. In this article, I will discuss some important effects of high atmospheric pressure on the human body.
Composition of air:
| Gases present in the air | % of gas in the air | partial pressure in mm. of Hg |
| Nitrogen | 78.06% | 593.25 |
| Oxygen | 20.98% | 160 |
| CO2 | 0.03% | 0.23 |
| Inert gases | 0.93% | 7.068 |
Partial pressure is the pressure exerted by anyone gas in a mixture of gases, and the total pressure of the gas mixture is the sum total of the partial pressures of gases present in the gas mixture. Air is a mixture of gases as stated above.
The partial pressure of a gas is calculated as below:
The partial pressures of Nitrogen= % of the nitrogen in the air is multiplied by total atmospheric pressure divided by 100 which is 78.06 x760 divided by 100 =593.25 mm. of mercury.
By this method, the partial pressure of oxygen is 160mm. of mercury and that of Inert gases and CO2,are7.068 and 0.23mm. of mercury. respectively.
Boyl’s law: Volume of a gas is inversely proportional to the pressure exerted on it.
( temperature is constant.) Suppose when pressure is X1 atmospheric pressure, the volume of air is V1. If atmospheric pressure rises to 2X, the volume of air will decrease to half 0.5 V. and so on.
Dalton’s law: States that the total pressure of a gas mixture is the sum total of the partial pressures of gases present in the gas mixture. Air is a mixture of gases as stated above and obeys this law.
Henry’s law: states that the amount of gas dissolved in any solution is directly proportional to the partial pressure of the gas.
Volume of a gas is directly proportional to temperature. When the temperature rises volume of a gas will increase and vice versa, when pressure is constant.
Diffusion of a gas in a liquid depends on the pressure differences and it moves from high to low pressure. When pressure of the gas is more it will enter in the liquid and when pressure decreases gas will come out from the liquid. Solubility of a gas differs in different liquids.
Atmospheric pressure becomes double at 10 meters below the sea level, volumes of gas will decrease to half. Due to raised pressure, Oxygen and Nitrogen will enter into the body fluids and tissues. Increased oxygen will cause oxygen toxicity and excess nitrogen will cause nitrogen narcosis.
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