Changing Membrane Potential

Question 1

What units are membrane potential measured in

Answer 1

Milivolts

Question 2

How do you measure membrace potentials

Answer 2

Using a microelectrode to penetrate the cell membrane

Question 3

What are microelectrodes filled with

Answer 3

A conducting solution such as KCl

Question 4

What 2 factors are important for the generation of membrane potential

Answer 4

Asymmetric distribution of ions and selective Ion Channels

Question 5

What is selective permeability

Answer 5

Movement of specific ions across the cell membrane

Question 6

What can travel though a phospholipid bilayer

Answer 6

Small, uncharged molecules

Question 7

What does the Nernst equation calculate

Answer 7

The equilibrium potential for an ion

Question 8

What is the resting potential for cardiac cells

Answer 8

-80mV

Question 9

What is the resting potential for nerve cells

Answer 9

-70mV

Question 10

What is the resting potential for smooth muscle cells

Answer 10

-50mV

Question 11

Why do some cells have lower resting potentials

Answer 11

Lower selectivity for potassium

Question 12

What is the main driving force behind the negative resting potential

Answer 12

Moment of potassium out of the cell

Question 13

What is an electrochemical gradient

Answer 13

Combination of electrical and concentration differences to determine the direction of the movement of the ion

Question 14

What is the resting potential for skeletal muscle

Answer 14

-90mV

Question 15

Why have some cells got a more negative resting potential

Answer 15

Lots of potassium ions

Question 16

What is the equilibrium potential

Answer 16

When the electrical and chemical gradients are equal

Question 17

What is depolarisation

Answer 17

Decrease in size of membrane potential

Question 18

What is hyperpolarisation

Answer 18

Increase in size of membrane potential

Question 19

What causes Changes in membrane potential

Answer 19

Changes in ion selectivity

Question 20

What is conductance

Answer 20

Is how the contribution of each ion to the membrane potential will depend on the ions permeability

Question 21

What is the GHK equation

Answer 21

Calculates membrane potential from lot of ions

Question 22

Give an example of a mechanical gated channel

Answer 22

Sound waves cause hairs in the ear to move which opens Ion Channels

Question 23

What are mechanical Gated channels

Answer 23

Channels that open or close in response to membrane deformation

Question 24

What sort of channels are used in fast synaptic transmissions

Answer 24

Ion Channels

Question 25

What do excitatory transmitters cause at synapses

Answer 25

Depolarisation

Question 26

What do inhibitory transmitters at synapses cause

Answer 26

Hyperpolarisation

Question 27

Give 2 examples of excitatory neurotransmitters

Answer 27

ACh and dopamine

Question 28

What is summation

Answer 28

When the amount of excitable or inhibitory transmitters exceeds the other to give an overall response

Question 29

What 2 types of transmitters are released in fast synaptic transmission

Answer 29

Excitatory and inhibitory

Question 30

What type of receptor is used in slo synaptic transmission

Answer 30

GPCRs

Question 31

How much does the electrogenic pump continue to th resting potential

Answer 31

Not a lot

Question 32

What ion channels open in heart muscle to cause a plateau in charge

Answer 32

Calcium