Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
What would Vm look like for a local potential along an axon? Why does this happen?
|
Would fade out over time and distance (not enough to depolarize cell and open Na+ channels; leak out of ion channels along the way)
|
|
|
What motivation do ions have to move along an axon?
|
Ionic repulsion
|
|
|
Describe the path of ions when injected into an axon.
|
Propel along bc of ionic repulsion, collect at membrane bc membrane acts as capacitor.
|
|
|
Assume threshold is reached during depolarization of a neuron, describe the graph of an action potential using E values as reference points.
|
Starts at Vm, Na+ channels open, depolarize toward E of Na+, Na+ channels close, K+ channels open, approach E of K+ (beneath initial Vrest), K+ channels close, Na+/K+ pump works back up to Vrest
|
|
|
Why don't K+ channels open at same time as Na+ channels?
|
K+ channels are delayed rectifier channels; open more slowly in response to depolarization
|
|
|
What is the absolute refractory period? When does it occur?
|
Na+ channels are inactivated and cannot be re-opened no matter what the stimulus; occurs under spike in action potential graph
|
|
|
What is the relative refractory period? When does it occur?
|
Have to stimulate harder to get an AP; occurs during Na+/K+ pump part of graph to get back up from hyperpolarization
|
