Action Potential

Question 1

Define action potential

Answer 1

Short lasting (1-2ms) electrical event in which the electrical membrane potential of a cell rapidly rises and falls

Question 2

Define depolarisation

Answer 2

When the membrane potential becomes more positive

Question 3

Define hyper polarisation

Answer 3

When the membrane potential becomes more negative

Question 4

What generates the resting membrane potential

Answer 4

Potassium leak channels
-make the inside of the cell more negative, then reach equilibrium

Question 5

Outline voltage gated sodium channels structure

Answer 5

Large single alpha subunit- ion conducting pore
4 domains, each containing 6 transmembrane segments
One or more beta subunits- accessory, bind onto the side and regulate gating mechanisms, kinetics etc

Question 6

When do voltage gated sodium channels open

Answer 6

In response ti depolarisation of the membrane potential, depolarising the membrane further, opening more Na channels

Question 7

What happens when potassium channels are activated

Answer 7

Activated by depolarisation
Potassium ions leave the cells, leading to hyperpolarisation
Can cause an overshoot-afterhyperpolarisation