02b: Local Potentials Flashcards Preview

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Flashcards in 02b: Local Potentials Deck (16):
1

In cell, the "resistance" is represented by:

Ion channels that allow movement of charges

2

For a constant density of ion channels, the larger the membrane area, the (larger/smaller) the resistance.

Smaller

3

How does capacitance change from one cell to another?

All cells have about the same Cm value

4

Cm value for typical cell is:

1 (micro)F/cm(squared)

5

What are the factors that determine the time constant?

Product of the membrane's:
1. Resistance
2. Capacitance

6

T/F: Any local voltage change produced by current across a nerve cell membrane will be affected by its passive properties.

True

7

T/F: Velocity with which nerve fiber conducts A.P. is independent of time constant.

False

8

A short time constant means nerve cell membrane depolarization can be (quicker/delayed/not affected).

Quicker

9

Axons with short time constant have (slower/equal/faster) conduction velocity than other axons.

Faster

10

The space constant represents what?

How far the current will spread along inside of axon

11

(Large/small) lambda means that current will flow (faster/further).

Large; further

12

Current flows further in membrane with (high/low) membrane resistance and (high/low) internal/external resistance.

High; low

13

T/F: Space constant is independent of physical properties of axon/dendrite.

False

14

T/F: Space constant is dependent on width of axon/dendrite.

True

15

A larger axon has a (lower/equal/higher) internal resistance compared to smaller axon.

Lower

16

T/F: An advantage of myelinated axons is that less metabolic E is needed to maintain concentration gradient.

True