Resting Membrane Potential

Question 1

Name the factors which determine the selectivity of ion channels ?

Answer 1

1. Charge lining the channel

2. Size of channel

Question 2

Name the types of ion channels?

Answer 2

1. Leaky channels
2. Gated channels
3. Na / K pump

Question 3

Name ion channels responsible for generation of resting membrane potential?

Answer 3

1. K leaky channel

2. Na / K pump

Question 4

Name the Factors affecting movements of ions across a membrane ?

Answer 4

1. Net force ( concentration + electrical force)

2. Conductance/ permeability

Question 5

Define graded potential & mention its characteristics as regard: origin ? Type of channel ? Conductance ? Amplitude ? Duration ? Polarity ? Summation ?

Answer 5

1. Origin: produced at dendrites and soma of a neuron
2. Type of channel : ligand or mechanically gated
3. Conduction : localized
4. Amplitude : varies depending on the strength of stimulus
5. Duration : milliseconds or minutes
6. Polarity : can depolarize ( excite) or hyperpolarize ( inhibit) a neuron
7. Summation : capable of summation

Question 6

What is the name of graded potential in the postsynaptic membrane & motor end plate?

Answer 6

Postsynaptic potential/ endplate potential

Question 7

Mention the equilibrium potential for K+ & Na+, and which equilibrium potential will determine
the resting membrane potential, and why?

Answer 7

K+: -94mV
N+: +61
RMP is near to the equilibrium of K+, as the membrane leaky
channels for K + is opened under resting conditions, thus the membrane is selectively permeable to
K+.