Nerve Impulse Transmission

Question 1

What is nerve impulse definition

Answer 1

A signal transmitted along a nerve fibre

Question 2

What is resting membrane potential

Answer 2

A state where there is no net flow of ions across the membrane

Question 3

What does the transmission of a nerve impulse require

Answer 3

Changes in the membrane potential of the neurons plasma membrane

Question 4

What’s an action potential definition

Answer 4

A wave of electrical excitation along a neurons plasma membrane

Question 5

What’s neurotransmitter’s definition

Answer 5

Chemicals that transmit a signal across a synapse

Question 6

What do neurotransmitters do

Answer 6

Initiate a response by binding to their receptors(ligand gated ion channels) at a synapse

Question 7

LEARN DIAGRAM SIMPLE BUT LEARN

Question 8

Depolarisation definition

Answer 8

A sudden change in membrane potential usually from a negative to positive internal charge

Question 9

What does depolarisation of the plasma membrane as a result of entry of positive ions do

Answer 9

Triggers the opening of voltage gated sodium channels and further depolarisation occurs

Question 10

What restores the resting membrane potential

Answer 10

Inactivation of the sodium channels and the opening of potassium channels restores the resting membrane potential

Question 11

What does binding of neurotransmitter do

Answer 11

Triggers the opening of ligand gated ion channels at a synapse

Question 12

What happens when sufficient ion movement occurs and the membrane is depolarised at the plasma membrane

Answer 12

The opening of voltage gated sodium channels is triggered and the sodium ions enter the cell down their electrochemical gradient

Question 13

What does sodium ions entering the cell down their electrochemical gradient do

Answer 13

Leads to a rapid and large change in the membrane potential

Question 14

What happens a short time after opening the sodium channels

Answer 14

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

Question 15

What’s step 1 of sodium potassium ions moving in membrane

Answer 15

Stimulas starts the rapid change in voltage or action potential. This must reach above a threshold voltage to start membrane depolarisation

Question 16

What’s step 2 of sodium potassium ions moving in membrane

Answer 16

Depolarisation is caused by a rapid rise in membrane potential opening of sodium channels non the cellular membrane, resulting in a large influx of sodium ions

Question 17

What’s step 3 of sodium potassium ions moving in the membrane

Answer 17

Membrane repolarisation results from rapid sodium channel inactivation as well as a large effluent of potassium ions resulting from activated potassium channels

Question 18

What’s step 4 of sodium potassium ions moving in the membrane

Answer 18

Hyperpolarisation is a lowered membrane potential caused by the efflux of potassium ions and closing of the potassium channels

Question 19

What’s step 5 of sodium potassium ions moving in the membrane

Answer 19

Resting state is when membrane potential returns to the resting voltage that occurred before the stimulas occured

Question 20

What does depolarisation of a patch membrane cause

Answer 20

Neighbouring regions of membrane to depolarise and go through the same cycle as adjacent voltage gated sodium channels are opened

Question 21

Learn depolarisation, action potential and repolarisation diagrams

Question 22

What happens when the action potential reaches the end of the neuron

Answer 22

It causes vesicles containing neurotransmitters to fuse with the membrane, this releases neurotransmitter which stimulates a response in a connection cell

Question 23

What does restoration of the resting membrane potential allow

Answer 23

The inactive voltage gated sodium channels to return to a conformation that allows them to open again in response to depolarisation of the membrane

Question 24

How are ion concentration gradients re established

Answer 24

By sodium potassium pump which actively transports ions in and out of the cell

Question 25

What happens after repolarisation

Answer 25

The sodium and potassium ion concentration gradients are reduced

Question 26

What does the sodium potassium pump do in nerve impulse stuff

Answer 26

Restores the sodium and potassium ions back to resting potential levels