Nerves 3

Question 1

What is the threshold potential?

Answer 1

About -55mV

Question 2

What will happen when the membrane potential hits -55mV?

Answer 2

An action potential will be fired

Question 3

What is a generator potential?

Answer 3

A graded potential occurring at sensory nerves

Question 4

What is an EPSP?

Answer 4

A generator potential that will depolarise the cell

Question 5

What is a IPSP?

Answer 5

A generator potential that will hyperpolarise the cell

Question 6

What is the graded potential between a motor neurone and a muscle called?

Answer 6

End plate

Question 7

What is the function of graded potentials?

Answer 7

To decide whether or not the stimulus is great enough for a response

Question 8

4 examples of graded potentials

Answer 8

• Generator
• Post synaptic
• Endplate
• Pacemaker

Question 9

4 key properties of graded potentials

Answer 9

• Excitatory
• Non-propegating
• Decremental
• Local

Question 10

Why are graded potentials decremental?

Answer 10

The current leaks out of the cell as it travels down it

Question 11

What is shown by the amplitude of a graded potential?

Answer 11

Signal intensity

Question 12

How can graded potentials generate an IPSP?

Answer 12

• Opening Cl channels on the post synaptic neurone

Question 13

How are fast IPSP’s generated?

Answer 13

• Opening ionotropic Cl channels

Question 14

How are slow IPSP’s generated?

Answer 14

• By binding to g-protein coupled receptors that open potassium channels causing K to leave the cell

Question 15

What 2 neurotransmitters will trigger an IPSP?

Answer 15

• Glycine

- GABA

Question 16

How are fast EPSP’s generated?

Answer 16

• Opening Na/K channels

Question 17

How are slow EPSP’s generated?

Answer 17

• Blocking potassium channels that cause potassium to leave the cell

Question 18

What is meant by the fact that graded potentials can summate?

Answer 18

• Two excitatory/inhibitory signals can add to each other

Question 19

What is temporal summation?

Answer 19

Input from the same stimulus add up to each other (turning on a tap, turning it off, then turning it back on again)

Question 20

What is spatial summation?

Answer 20

2 different stimuli add to each other (turning on 2 taps at the same time)

Question 21

What is synaptic integration?

Answer 21

• All inputs taken into consideration

- Action potential decided

Question 22

Why do synapses nearer the axon hillock have a better chance of generating an AP?

Answer 22

• Decremental aspect
• Have to travel less distance so less signal is lost
• Axon hillock is what decided to fire an AP