02b: Local Potentials Flashcards
In cell, the “resistance” is represented by:
Ion channels that allow movement of charges
For a constant density of ion channels, the larger the membrane area, the (larger/smaller) the resistance.
Smaller
How does capacitance change from one cell to another?
All cells have about the same Cm value
Cm value for typical cell is:
1 (micro)F/cm(squared)
What are the factors that determine the time constant?
Product of the membrane’s:
- Resistance
- Capacitance
T/F: Any local voltage change produced by current across a nerve cell membrane will be affected by its passive properties.
True
T/F: Velocity with which nerve fiber conducts A.P. is independent of time constant.
False
A short time constant means nerve cell membrane depolarization can be (quicker/delayed/not affected).
Quicker
Axons with short time constant have (slower/equal/faster) conduction velocity than other axons.
Faster
The space constant represents what?
How far the current will spread along inside of axon
(Large/small) lambda means that current will flow (faster/further).
Large; further
Current flows further in membrane with (high/low) membrane resistance and (high/low) internal/external resistance.
High; low
T/F: Space constant is independent of physical properties of axon/dendrite.
False
T/F: Space constant is dependent on width of axon/dendrite.
True
A larger axon has a (lower/equal/higher) internal resistance compared to smaller axon.
Lower
