Diffusion of oxygen through the mouse ear

Area of Science:

• Physiology
• Biophysics

Background:

• Understanding oxygen diffusion is crucial for various physiological processes.
• The mouse ear serves as a model for studying oxygen transport in biological tissues.

Purpose of the Study:

• To quantify oxygen diffusion across the mouse ear.
• To identify the primary barriers to oxygen transport.
• To model oxygen diffusion using experimental data.

Main Methods:

• Polarographic measurements of oxygen tension under conditions of no blood flow.
• Experiments involving splitting the ear and removing the stratum corneum.
• Application of a multi-layer diffusion model.

Main Results:

• The stratum corneum is the main barrier to oxygen diffusion, with a permeability of 1.2 X 10^-8 ml O2 atm^-1 cm^-1 S^-1.
• The permeability of the rest of the ear tissue is 4.7 X 10^-7 ml O2 atm^-1 cm^-1 S^-1.
• Inhibiting tissue respiration or cooling the ear significantly reduced oxygen gradients.

Conclusions:

• The stratum corneum significantly impedes oxygen diffusion in the mouse ear.
• A multi-layer diffusion model effectively describes oxygen transport.
• Factors like tissue respiration and temperature influence oxygen gradients.