Generation of a nerve impulse (C&S)

Question 1

Step 1

Answer 1

Binding of a neurotransmitter triggers the opening of ligand-gated ion channels at a synapse.

Question 2

Step 2

Answer 2

Ion movement occurs and there is
depolarisation of the plasma membrane.

Question 3

Step 3

Answer 3

If sufficient ion movement occurs, and the membrane is depolarised beyond a threshold value, the opening of voltage-gated sodium channels is triggered and sodium ions enter the cell down their electrochemical gradient.

Question 4

Step 4

Answer 4

This leads to a rapid and large change in the membrane potential.

Question 5

Step 5

Answer 5

A short time after opening, the sodium channels become inactivated.

Question 6

Step 6

Answer 6

Voltage-gated potassium channels then open to allow potassium ions to move out of the cell to restore the resting membrane potential.