Question

Match the following
$\begin{array}{cc}\text{Location}& \text{Partial Pressure of Oxygen (mm Hg)}\\ \text{1. Alveoli}& \text{i) 40}\\ \text{2. Oxygenated Blood}& \text{ii) 104}\\ \text{3. Tissue}& \text{iii) 95}\end{array}$

• A. 1-ii, 2-iii, 3-i
• B. 1-iii, 2-i, 3-ii
• C. 1-i, 2-iii, 3-ii
• D. 1-ii, 2-i, 3-iii

Answer 1

The correct option is A 1-ii, 2-iii, 3-i

Partial pressure is the pressure exerted by the gas present in a mixture of gases. Alveoli is a sac-like structure that is the primary site of the exchange of gases. The exchange of gases (oxygen and carbon dioxide) takes place with the help of diffusion which is based on the pressure gradient. In other words, the transport of gas occurs from high pressure to low pressure areas. This diffusion is also affected by the solubility of the gases and the membrane thickness apart from the pressure gradient. Gaseous exchange occurs from alveoli to blood and blood to tissues for oxygen. Similarly, for carbon dioxide, the exchange happens from tissues to blood and then from blood to alveoli.
The following table provides the data for the partial pressure of oxygen and carbon dioxide:
$\begin{array}{ccc}\text{Location}& \text{Partial Pressure of Oxygen (mm Hg)}& \text{Partial Pressure of Carbon dioxide (mm Hg)}\\ \text{Atmospheric air}& 159& 0.3\\ \text{Alveoli}& 104& 40\\ \text{Oxygenated Blood}& 95& 45\\ \text{Deoxygenated Blood}& 40& 40\\ \text{Tissue}& 40& 45\end{array}$