Question

Huf and Ussing performed experiments where they measured a current flowing between two chambers when each chamber had been filled with a saline solution and the chambers were separated by the skin of a frog. They noted that this current existed whether or not there was a concentration gradient for Na+ ions between the chambers and that Na+ ions and not Li+ moved between the chambers. Explain and describe the source of the current flow.

Answer 1

Huf and Ussing experiment was conducted the experiment to measure the properties of epithelial membrane. Ussing chamber consisits of two halfs which is separated by an epithelial membrane and this system is used to measure transport of ions, nutrients or several drugs which takes place across the membrane.

Huf and Ussing used frog skin as a epithelial barrier for their experiment. They put differnt concentration of salt solution on either side of the barrier and used a poteintial meter to check . the difference the balance of charges at both sides of the chamber. They also used a current meter to look how salts are traveled fro one side to another.

Frog skin is used here as source of current flow. Frog skin has several layers of cells starting from serosa to mucos a it consisits of basal germinative layer, next is spiny stratum which is further followed by stratum granulosum. These layers are filled with cells with cytosolic granules and also special structues like tight jucntion, gap junctions and desmosomes. All these arrangements give frog skin a high resistance which is around 1000–3000 ohms.