Henry's Law is important for understanding how gases mix with blood.

In simple terms, Henry's Law says that the amount of gas that can dissolve in a liquid depends on how much of that gas is above the liquid.

When we look at the lungs, this means that the levels of oxygen (O₂) and carbon dioxide (CO₂) in small air sacs called alveoli affect how well these gases can mix with blood.

Key Points:

1. Solubility Formula:

   • The formula looks like this: $C = k_H \cdot P_g$
   • Here’s what the letters mean:
     • $C$ is the amount of gas that dissolves.
     • $k_H$ is a special number for each gas.
     • $P_g$ is the level of that gas above the liquid.

2. Example with Oxygen:

   • When we take a breath, there’s a lot of oxygen in the alveoli.
   • Because of Henry’s Law, more oxygen can dissolve in the blood.
   • This helps the body transport oxygen to the places it’s needed.

3. Example with Carbon Dioxide:

   • On the other hand, carbon dioxide is easier to dissolve in blood than oxygen.
   • It moves from the body’s tissues into the blood easily.
   • This makes it simple for the body to get rid of carbon dioxide when we breathe out.

All of this helps our respiratory system work well, making sure that our body gets the right amount of oxygen and removes carbon dioxide, keeping everything balanced.