Electrical Membranes (Theme B)

Question 1

Describe resting membrane potential (RMP)

Answer 1

Na+/K+ ATPase pump transports 3Na+ OUT of the cell and 2K+ INTO the cell. Therefore inside the cell: [K+] > extracellular fluid and [Na+] < extracellular fluid

The membrane is more permeable to K+ than to Na+ → K+ diffuses out of the cell faster than Na+ diffuses into the cell from the surrounding fluid

Therefore, the inside of the cell is more negative than the outside of the cell → RMP

Question 2

What does an extracellular recording of an AP involve? (Experimentally)

Answer 2

Inserting a recording & reference electrode in close proximity outside a group of cells