Raw Science: Resp Phys 4 – The Gas Laws

Raw Science 4

Gas Laws

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.

Carl Sagan

Welcome to Basic Science Clinic Raw Science episode 4. We are close to embarking on the descent down the oxygen cascade, en route we will examine the key contributors to these stepwise decrements in oxygen partial pressure that coax the gas down to the level of the mitochondria. To grasp the concepts essential to the physiology of this pathway you need to understand the fundamentals of gas behaviour, enter the gas laws.

In this pod we will cover:

• Boyle’s, Charles’, Guy-lussac’s laws
• Avogadro’s number
• Dalton’s and Henry’s laws
• Saturated vapour pressure & boiling point
• The concept of in vivo partial pressures

Raw Science Factoids

Increasing ambient pressure from 1 to 2 atm will decrease the volume of 1L water by <0.01% and decrease the volume of 1L air by 50%.

At an oceanic depth of 40m an FiO₂ 0.21 results in a PiO₂ > 400 mmHg and FiO₂ 1.0 gives PiO₂ > 2000 mmHg, resulting in tissue hyperoxia.

Opening a soda can drops the pressure of the CO₂ gas above the liquid that has set up an equilibrium in accordance with Henry’s law. This results in CO₂ rushing out of solution to reach a new equilibrium with ambient, atmospheric CO₂ partial pressure.