4: Action potentials

Question 1

Describe the relationship between the permeability of the membrane to the conductance/action potential

Answer 1

The more permeable the membrane to a particular ion, the greater the conductance of the membrane to that ion

Question 2

What are transmembrane domains?

Answer 2

Protein of the voltage gated Na+ channel has 4 subunits which are already connected. The parts in the subunit are called the transmembrane domain

Question 3

What type of channel are Na+

Answer 3

Voltage gated

Question 4

What are the three sections of voltage gated Na+ channels

Answer 4

1. Voltage sensor -ON
2. Selectivity filter
3. Inactivation gate -OFF

Question 5

Describe how the inactivation gate works

Answer 5

“ball and chain model”

- Look through lecture slides

Question 6

What drug are voltage gated Na+ channels blocked by?

Answer 6

Tetrodotoxin

Question 7

What are voltage gated K+ channels blocked b

Answer 7

tetrathylammonium

Question 8

Describe the action/movement of action potentials

Answer 8

slides

• Stimulus-gated Na+ channels open
• Voltage-gated Na+ channels open
• Voltage-gated Na+ channels close
• Voltage-gated K+ channels open
• Voltage-gated K+ channels close

Question 9

Describe the absolute refractory period

Answer 9

slides

Question 10

Describe the relative refractatory period

Answer 10

slides

Question 11

List methods to improve action potential conduction velocity

Answer 11

• Increase axon diameter -decrease r(in)
• Increase axon insulation -increase m
• Saltatory conduction between nodes of Ranvier