Passive Properties Flashcards
What three positive properties properties are important to electrical signaling?
- Membrane resistance
- Axial resistance
- Membrane capacitance
How can you adjust passive properties to promote fast signaling?
- Increase membrane resistance.
- Lower axial resistance.
- Lower membrane capacitance
Are passive signals (local graded potentials), hyper or depolarizing?
Both
Are active signals (action potentials) hyper or depolarizing
Depolarizing
How do they record membrane potential?
Stimulating electrode and recording oscilloscope
Why does injecting a positive current result in depolarization?
When you inject a positive current you inject positive ions into the negative cell, making it less negative.
When you inject positive current, what is being measured?
The current that leaves the cell
Why does the membrane potential change more slowly than the current pulse?
The lipid bilayer holds onto some charge in the beginning.
What determines the change in membrane potential?
Membrane (input) resistance
How does neuronal size affect input resistance?
Larger equals more surface area. More surface area equals more channels. More channels lowers input resistance.
What is specific membrane resistance?
Property of membrane independent of size of the cell. Does depend on axon diameter though.
What is specific membrane capacitance?
Capacitance independent of size of the cell. Does depend on axon diameter though.
How does neuronal size affect input capacitance
Larger size equals more space for storage. More space equals more charge.
What is membrane current?
Total current
What is ionic current?
Current that goes through ion channels
