Week 2; changes in membrane potential

Question 1

graded potentials

Answer 1

short lived localized signals over short distances. starts at dendrites and soma. They can be depolarization or hyperpolarization. STARTS by a chemically gated ion channel

Question 2

action potentials

Answer 2

long distance signals of axons, starts at the axon hillock. do not decay over distance, reversal of membrane potential, from negative to positive. principal way neurons send signals.

Question 3

depolarisation- EXCITATORY

Answer 3

a decrease in membrane potential - closer to 0. Inside of membrane becomes less negative as Na+ channels open, and there is a higher chance of creating an AP

Question 4

hyperpolarisation - INHIBITORY

Answer 4

an increase in membrane potential - away from one. Inside of membrane becomes more negative as K leaves, less chance of AP

Question 5

Current

Answer 5

the flow of electrical charge carried by ions

Question 6

4 stages of an action potential

Answer 6

1. rest
2. depolarisation
3. repolarisation
4. hyperpolarisation

Question 7

3 steps in voltage gated sodium channels

Answer 7

1. resting stage activation gate opens
2. opened by depolarisation
3. inactivation gate closes

Question 8

propagation of an action potential

Answer 8

sodium channels in one membrane area cause local currents that cause opening of adjacent voltage gated channels

Question 9

absolute refractory period

Answer 9

time from opening sodium channel until the resetting of the channels, why they dont travel backwards

Question 10

relative refractory period

Answer 10

whilst hyperpolarising, needs a big stimulus for AP to be created