2.2 -- Membrane Potential Flashcards
What is the cause of the resting membrane potential?
Some K+ leak through the leaky K+ channels
What keeps the concentration gradients?
Na+/K+ ATPase
Which two ions have a higher concentration outside the cell?
Na+ and Cl-
What ion has a higher concentration inside the cell?
K+
What channels are always open?
K+ channels
The proteins inside the cell have what charge?
Negatively charge
The difference in charge is called what?
Potential difference
Why does K+ not rush out of the cell?
Electrical gradient
The cell membrane is most permeable to what ion at rest?
K+
Neurons are usually at what mV?
-70 mV
In most cells, the resting membrane potential is between -65 mV and what?
-85 mV
When does depolarization occur? What normally causes it?
When positive ions enter the cell, typically Na+
When does hyperpolarization occur? What normally causes it?
When positive ions leave the cell (K+) or negative ions enter the cell (Cl-)
Is hyperpolarization inhibitory or excitatory? What about depolarization?
Hyperpolarization – Inhibitory
Depolarization – Excitatory
What type of channel is a receptor and a channel?
Ligand-gated
What type of channel opens at a specific voltage?
Voltage-gated
What is summation?
Keeping channels open for longer than needed or multiple channels being open near each other
What is a graded potential?
Small, localized signal
Summation of depolarizing potential does what to the neuron?
Activates the neuron
Can a graded potential be hyperpolarization, depolarization, or both?
Both
