How Nerves Work 3

Question 1

What is a ligand?

Answer 1

A substance that forms a complex with a biomolecule

Question 2

What are some examples of graded potentials?

Answer 2

Generator potential (at sensory receptor)

Postsynaptic potential (at synapses)

Endplate potential (at neuromuscular junction)

Pacemaker potential (in pacemaker tissue)

Question 3

What is the job of the graded potential?

Answer 3

To get the cell to threshold and fire an action potential

Question 4

How are graded potentials decremental?

Answer 4

They don’t trevel very well along membranes

Question 5

What does decremental mean?

Answer 5

Process of gradually becoming less

Question 6

Why are graded potentials decremental?

Answer 6

The current flows out of the graded potential as it travels along the axon

Question 7

What distance can graded potentials travel?

Answer 7

Only short due to being decremental

Question 8

How are graded potentials graded?

Answer 8

They may be of a higher intensity or a lower intensity

Question 9

What is the size of the graded potential proportional to?

Answer 9

The size of the stimuli

Question 10

Show how graded potentials can be polarising or depolarising on a graph?

Question 11

What is the threshold for opening Na⁺ gated channels and firing an action potential?

Answer 11

-55mV

Question 12

What is an excitatiry post synaptic potential (EPSP)?

Answer 12

Anything that takes the potential towards threshold

Question 13

What is an inhibitory post synaptic potential (IPSP)?

Answer 13

Anything that takes the potential away from threshold

Question 14

What happens once a graded potential reaches threshold?

Answer 14

An action potential is fired

Question 15

How does a channel being part of the receptor affect the response?

Answer 15

Channel/receptor combinations produce a faster response, whereas if the channel uses a seperate receptor it produces a slower response

Question 16

What channels produce an IPSP response?

Answer 16

Cl^- (fast)

K⁺ (slow)

Question 17

Do Cl^- channels produce a fast or slow response?

Answer 17

Fast

Question 18

Do K⁺ channels produce a fast or slow response?

Answer 18

Slow

Question 19

What channels produce an EPSP?

Answer 19

Na⁺ (fast, also permeable to K⁺ due to them both having a charge of +1)

Closing leaky K⁺ (slow)

Question 20

Do Na⁺ channels produce a fast or slow response?

Answer 20

Fast

Question 21

Does closing leaky K⁺ channels create a fast or slow response?

Answer 21

Slow

Question 22

What are presynaptic potentials generated by?

Answer 22

Neurotransmitter opening or closing ion channels

Question 23

Are graded potentials generated by ligand or voltage gated channels?

Answer 23

Ligand

Question 24

Are action potentials generated by voltage or ligand gated channels?

Answer 24

Voltage

Question 25

What is synaptic integration?

Answer 25

The summation of graded potentials to reach threshold

Question 26

Why are graded potentials generated next to the axon (where the axon potential is generated) more likely to reach threshold than one further away?

Answer 26

Graded potentials are decrimental

Question 27

What is temporal summation?

Answer 27

Stimulating the same potential one after an other

Question 28

What is spatial summation?

Answer 28

Stimulating two potentials at the same time

Question 29

What kinds of synapses can summate?

Answer 29

Both inhibatory and excitatory

Question 30

Where do synapses that are IPSP tend to be located?

Answer 30

On the soma