AP I

Question 1

So for a given length of axon the intracellular resistance is _______ than ECF resistance which has more _______

Answer 1

• much greater

- area

Question 2

ion channels act like _______. Ions continue to _______ after positive charges have ceased flowing into the cell. The result of this is that l_______

Answer 2

• resistors
• leak out
• less current is delivered down the axon than was originally inserted.

Question 3

Booster stations act by _______. Action potentials work in essentially the same way. The detector that senses the decaying message is the _______ and the energy source that propagates the message is the_______

Answer 3

• applying an energy boost to a decaying electrical signal when the incoming signal is detected
• voltage-gated sodium channel
• Na “battery”, i.e. the Na gradient that can inject extra positive charge into the cell

Question 4

The _______ the membrane resistance becomes, the farther the voltage can spread down the axon, because it means _______

Answer 4

• larger

- there are fewer ion channels for charges to leak out of

Question 5

Membrane capacitance is _______. These charges create _______

Answer 5

• the ability of charge to accumulate on two sides of a membrane
• an electrical force that that pulls oppositely charged ions toward it

Question 6

Reducing membrane capacitance _______ the passive spread of voltage.

Answer 6

increases

Question 7

When current is injected into the cell, it must follow either through the _______ or into the _______

Answer 7

• ion channels (as resistors)

- membrane capacitor

Question 8

_______ internal resistance will slow the spread of voltage, as charge is _______ to the surrounding fluid.

Answer 8

• Increased

- lost

Question 9

Resistance _______ as cross-sectional area decreases

Answer 9

increases