Membrane potentials - graded potentials

Question 1

What are graded potentials?

Answer 1

primarily generated by sensory input, causing a change in the conductance of the membrane of the sensory receptor cell.

depolarise the cell to threshold and fire an action potential

Question 2

What are examples of graded potentials?

Answer 2

generator potentials

postsynaptic potentials

endplate potentials

pacemaker potentials

Question 3

What is a generator potential?

Answer 3

at sensory receptors

Question 4

What is a postsynaptic potential?

Answer 4

at synapse

Question 5

What is an endplate potentials?

Answer 5

at neuromuscular junction

Question 6

What is a pacemaker potential?

Answer 6

in pacemaker tissue

Question 7

Do graded potentials travel well along the axon?

Answer 7

no graded potential’s electrical current get smaller as they travel along the membrane

useful over short distances

Question 8

Are graded potentials hpo or depolarising?

Answer 8

both

Question 9

Ho wmany snaspes doe sone neurone have?

Answer 9

many

Question 10

Can graded potentials summate together?

Answer 10

yes, can lead to an action potential

Question 11

What is the red and blue arrow?

Answer 11

red = concentration gradient

blue = electrical gradient

Question 12

What dictates the electrical gradient?

Answer 12

the charge of the ion

chloride wont flow into the cell because of the negatively charge ion wont flow to the negative intracellular charge.

Question 13

describe this diagram

Question 14

If you want to use depolarise the cell, what channel would you open?

Answer 14

calcium

also sodium but it effects lots of enzymes

Question 15

If you want to hyperpolarise a cell, what channels would you open?

Answer 15

potassium

chloride

Question 16

what would you do to potassium leaky channels to depolarise the cell?

Answer 16

close them

Question 17

What are 2 ways the cell manipulates the ion channels to cause hyperpolarisation?

Answer 17

neurotransmitter bind to the ionotropic chloride receptor, chloride comes in and hyperpolarise

= away from AP, inhibitory

open even more potassium channels. via GPCR, metabotropic receptor

Question 18

What is the Cl- receptor called?

Answer 18

ionotropic

Question 19

What is the potassium receptor called?

Answer 19

metabotropic

Question 20

Is the ionotropic chloride channel fats or slow?

Answer 20

fast

Question 21

Is the metabotropic potassum chnnel fast or slow?

Answer 21

Slow, there is a delay

Question 22

what is a monovalent cation channel?

Answer 22

not fussy, lets ions with a charge of one through

Question 23

how does the cell depolarise post-synaptically?

Answer 23

neurotransmitter binds to the monovalent cation channel
- sodium moves in due to the concentration and electrical potentials
- small amount of potassium moves out (small electrical potential)
- fast

block the potassium leaky channels via GPCR
- slow