Question

Partial pressure of oxygen in the inspired and expired air is respectively.
A.$159$ and $116mm$ $Hg$
B.$158$ and $40mm$ $Hg$
C.$100$ and $95mm$ $Hg$
D.$40$ and $95mm$ $Hg$

Answer 1

Hint: The force exerted by a gas is known as partial pressure. The total pressure is equivalent to the sum of the partial pressures of all the gases in a mixture. The importance of partial pressure in forecasting gas movement is very high.

Complete answer: Simple diffusion, which is mostly dependent on pressure or concentration gradient, is used to diffuse gases. The rate of diffusion is determined by a number of factors which are Gases' solubility, Membrane thickness, and Partial pressure.

Each gas exerts pressure in a container filled with more than one gas, which is known as partial pressure. The partial pressure of any gas within the container is its pressure. Partial pressure is the pressure exerted by one of the gases in a mixture if it occupies the same volume on its own.
We know that gases diffuse according to their partial pressure. Oxygen is diffused from atmospheric air (inspired) with a partial pressure of $159mm$ $Hg$ to the alveoli, which have a lower partial pressure of $116mm$ $Hg$. Hence this is the correct answer.
Therefore, the correct option is A) $159$ and $116mm$ $Hg$

Additional Information: The significance of partial pressure in forecasting gas flow cannot be underestimated. Remember that gases in two connected places try to equalise their pressure. A gas will flow from an area with a higher partial pressure to one with a lower partial pressure.

Note:
The partial pressure of carbon dioxide is a measurement of carbon dioxide in arterial or venous blood. It is sometimes used as a sign of adequate alveolar ventilation in the lungs. The partial pressure of carbon dioxide levels usually ranges from $35$ to $45mm$ $Hg$ under standard physiologic conditions.