Reference no: EM133261907

Diffusion is the movement of molecules across a semipermeable membrane from high concentration to low concentration. Diffusion is how the gas molecules (oxygen and carbon dioxide) move across the membrane. Just as humans exchange of gasses through the membrane of their lungs for breathing, skin breathing animals supply oxygen to their blood through diffusion of their skin.

Surface area plays an important role in cutaneous gas exchange. More surface area allows for more gas exchange so certain animals, such as amphibians, have adaptions such as skin folds to increase surface area. Thinner skin is also an adaption for enhanced diffusion across the skin. This allows the gasses to diffuse more readily. The article mentions that the thick skin of humans (relatively thick compared to the amphibians) is one example as to why their skin would not be sufficient for gas exchange at the level that lungs can supply oxygen to the bloodstream and carry out CO2. Also, the thicker the skin, the greater the distance for the gasses to reach the cutaneous capillaries.

The article mentions that, physiologically, venitalation for skin breathing occurs at its best when the animal moves through the water rather than remains still. This is because due to partial pressure, movement helps maintain a difference in pressures of a oxygen on either side of the barrier. Therefore, ability to maintain movement through water to maintain gas exchange is important in enhancing diffusion.