Action Potentials

Question 1

Sodium and potassium flow which ways?

Answer 1

sodium in, potassium out

Question 2

Is the driving force for sodium positive or negative?

Answer 2

negative

Question 3

Is the driving force for potassium positive or negative?

Answer 3

positive

Question 4

When the channels open what do the sodium and potassium membrane potentials head towards?

Answer 4

Ek or ENa

Question 5

Action potentials have specific what?

Answer 5

amplitude or size

Question 6

For any given nerve fibre an action potential conducts along it with what velocity?

Answer 6

constant

Question 7

How are sodium and potassium channels activated?

Answer 7

by membrane depolarisation

Question 8

Is the opening of sodium channels connected to positive or negative feedback?

Answer 8

positive

Question 9

Is the opening of potassium channels connected to positive or negative feedback?

Answer 9

negative

Question 10

What happens upon sustained depolarisation to sodium channels?

Answer 10

they become inactive

Question 11

Current loss means what?

Answer 11

passive signals do not spread far from their site of origin

Question 12

Longer length current (lambda) means what?

Answer 12

greater local current speed

Question 13

Is a Schwann cell a conductor or insulator?

Answer 13

insulator

Question 14

Where can current jump out of Schwann cell?

Answer 14

Nodes of Ranvier