Neuronal Signaling: Action Potentials Flashcards
Define receptor potential
Define postsynaptic potential.
The action potential is an _____________ electrical signal that depends on the opening of __________________.
- All-or-nothing
- Voltage-gated ion Channels
How many subunits does a voltage-gated ion channel have? What is the subunit made of?
What is the green area, the yellow, the blue, and the pink.
Explain how one subunit has a selectivity filter. And how it is gated.
Explain how voltage gating works. (Hint: it’s all about the S4 segment!)
Explain how opening a voltage gated sodium channel creates a positive feedback loop.
If Na+ ions being let into the cell force positive feedback loops, why don’t they keep flowing into the cell until the membrane potential reached equilibrium for Na+? (Side quiz: what is the eq?)
Side quiz: +60mV
The action potential only peaks around +30, because the voltage-gated Na+ channels close due to rapid inactivation.
How does rapid inactivation work?
There are amino acids that are the gate of the channel that immediately conform to a “door” that shuts the channel up when the channel is activated to let Na+ in.
What requirement must be met to initiate an action potential? Both term and function.
Voltage must reach the Threshold Potential.
Once the threshold voltage is met, what chemically happens?
Test:
What causes repolarization?
Opening of voltage-gated K+ channels.
What is this showing you?
K+ open much slower and are activated much longer.