Ion Channels and Action Potential

Question 1

What is a membrane potential?

Answer 1

Slight imbalance of positive/negative

Question 2

Biological membranes are not permeable to ions, but only to ( )

Answer 2

specialized proteins

Question 3

What type of channels are used for signaling?

Answer 3

Nonselective

Question 4

Nernst Equation

Answer 4

(60 mV/Z)*log10 (Xout/Xin)

Question 5

The point of equilibrium (Ek) is defined by the

Answer 5

Nernst Equation

Question 6

In cells in the body, the resting potential is above Ek in the range from -65 mV to -85 mV due to ( )

Answer 6

permeability of the membrane to Cl- and some small permeability to Na+ (leak channels)

Question 7

Incoming stimuli result in depolarization of the neuronal membrane due to opening of ( )

Answer 7

non-selective cation channels

Question 8

threshold potential

Answer 8

-40 mV

Question 9

within how long does the membrane potential return back to its resting potential?

Answer 9

3 ms

Question 10

During ( ) Na channels are partially recovered from inactivation and an AP can be generated as a result of a very strong stimulation

Answer 10

relative refractory period

Question 11

AP channels blocked by

Answer 11

neurotoxins

Question 12

puffer fish neurotoxin

Answer 12

tetrodotoxin

Question 13

shellfish neurotoxin

Answer 13

saxitotoxin

Question 14

adjacent regions of the axon are depolarized

Answer 14

electrotonic conduction

Question 15

How is AP velocity?

Answer 15

constant conduction velocity

Question 16

conduction velocity is determined by the ( ) of the neuron

Answer 16

cable properties

Question 17

How is AP amplitude?

Answer 17

non-decremental (constant)

Question 18

If the diameter of neuron is larger, is the AP propagation faster or slower?

Answer 18

faster

Question 19

voltage-gated sodium and potassium channels are highly concentrated in short exposed regions

Answer 19

Nodes of Ranvier