8 - Neurones Flashcards
When is a neurone considered to be in a resting state?
When it’s not being stimulated and therefore the outside (of the membrane) is more positively charged than the outside
What is the voltage of the membrane when it’s at resting potential?
-70mV
How is the resting potential maintained and created?
With the help of sodium-potassium pumps and potassium channels?
What do the sodium-potassium pumps do?
These pumps use active transport to move three sodium ions out of the neurone for every two potassium ions moved in.
What does the potassium ion channel do?
It allows facilitated diffusion of potassium ions out of the neurone, down their concentration gradient.
How is a sodium ion electrochemical gradient formed and what is it?
The sodium-potassium pumps move sodium ions out of the neurone, but the membrane isn’t permeable to sodium ions, so they can’t diffuse back in, causing a concentration gradient of ions (sodium electrochemical gradient).
How is the neurone positively charged?
Because of the sodium electrochemical gradient on the outside and the fact that potassium can use active transport to get into the cell, the outside is then positively charged.
