resting potential Flashcards
Describe the resting potential neurones have across their cell membrane
Negative resting potential across their cell membrane. More negative charge inside than their is outside
What is the potential difference/voltage
The electrical difference between the inside and the outside of a cell / difference between negative and positive ions that lie inside and outside the cell
What does this negative potential mean
Negative ions inside the cell have a tendency to leave and positive ions outside the cell have a tendency to enter. As opposite charges attract and the same ions repell
Define resting potential
The difference in electrical charge across the membrane while the neurone is at rest (the tendency for an ion to move inside or outside the cell)
What do we measure resting potential in
Millivolts (mV)
What is the resting potential in mV
-70mV
How is the resting potential maintained
Through keeping more positive ions outside the cell than inside
What mechanism is used to keep the resting potential
sodium-potassium pump
How does sodium-potassium pump work
It uses ATP to pump 3 sodium ions out of the cell and 2 potassium ions into the cell
What does the sodium-potassium pump cause
More potassium is inside the cell and more sodium is outside the cell. Neurone will have a more positive charge outside the cell than inside
What does the sodium potassium pump do as well as creating a negative resting potential
Changes the concentration of ions inside and outside the cell
What does the sodium-potassium pump do to the ion concentration
Results in a high sodium ion concentration inside the cell and a high sodium ion concentration outside the cell
What is the membrane of neurones permeable to?
potassium ions through potassium channels but not to sodium
What are the 2 gradients acting on the potassium ions
Electrical gradient and concentration gradient
What does the electrical gradient do to potassium ions
Pulls potassium ions into the cell
