Week 1 Flashcards
What are action potentials
Electrical signal. They are rapid changes in voltage of the cell.
What is the cells membrane potential
Voltage inside a cell relative to the outside
Resting membrane potential
No action potentials occurring
What controls permeability when cell is at rest
Leak channels
Electrogenic mechanisms
Produce a change in voltage because there’s net movement of either positive or negative ions from one side of membrane to another
What is the chemical force
When ions move through leak channel down their concentration gradient
What is the electrical force
Acts opposite to chemical force, attracts ions against their concentration gradient. Negative membrane potential will attract positive ions back into the cell.
What is the equilibrium potential
The membrane potential when the chemical and electrical forces are of equal magnitude so there’s no net movement of ions across cell membrane. Only electrical force changes to set up this equilibrium.
What is the chemical force set up by
The concentration gradient for an ion
What is the electrical force set up by
The membrane potential of the cell
Equilibrium potential for an ion
When membrane potential is reached at which the forces are balanced. Each ion has its own equilibrium potential.
When is the resting membrane potential equal to the equilibrium potential
If the membrane is only permeable to one ion
What cells membranes are only permeable to K+
Skeletal muscle cells and glial cells
What is the Nernst equation used for
To calculate the equilibrium potential for any ion
What is meant by driving force
When the chemical and electrical force do not cancel each other out, there’s a movement of ions in one direction
