Action potentials and synapse

Question 1

RMP

Answer 1

resting membrane potential in the cell is around -70mV
it is maintained through the ATPase K+/Na+ pump which shifts 3 Na+ out for every 2 K+ ions in.
a few K+ channels are open

Question 2

DEpolarised Potential

Answer 2

Na+ channels are open and Na+ ions flow into the cell and rapidly depolarise the cell to make it positive

Question 3

REpolarised

Answer 3

K+ channels are open and they cause the cell membrane potential to be driven, down and makes it negative again as the positve charges flow out of the cell again.

Question 4

HYPERpolarisation

Answer 4

positive ions flow out of the cell and this causes the cell to become even more negative and even further away from the threshold and the RMP.

Question 5

Step 1 of an action potential happening in a cell

Answer 5

a stimilus triggers the Na+ channels to open and allow the inwards diffusion of Na+ cations. this causes the membrane to depolarise.

Question 6

Step 2 of action potential

Answer 6

as the threshold potential is reached, the voltage gated Na+ channels all open and as more open more Na+ enters the cell and causes the cell to depolarise even further.

Question 7

step 3 of action potential

Answer 7

as the magnitude of action potential peaks at +30mV, the voltage gated Na+ membrane channels will close stopping the inflow of Na+ ions.

Question 8

step 4 of action potential

Answer 8

the voltage gates K+ ion channels will be triggered to open allowing the outward diffusion of K+ ions down their concentration gradient. and the potential drops back down.

Question 9

step 5 of action potential

Answer 9

after a brief period of hyper-polarisation by the out flux of K+ ions leaving the cell, the resting membrane potential is restored by the sodium potassium pump and the return of ions channels to their resting state.

Question 10

axon terminal

Answer 10

bouton/ knob shaped end of axon

Question 11

vesicles

Answer 11

sitting in the pre and they contain the chemical neurotransmitter that will be released.

Question 12

cytoskeleton

Answer 12

like scaffolding that keeps everything in the correct places - always there

Question 13

mitochondria

Answer 13

provides the energy needed for the processes of chemical neurotransmission

Question 14

voltage gated Ca2+ channels

Answer 14

very similar to the sodium potassium ion channels that only Ca2+ can go through them, very specific

Question 15

synaptic cleft

Answer 15

the space between the pre and the post that is filled with the neurotransmitter

Question 16

neurotransmitter receptors

Answer 16

the chemical binds to specific receptors for that chemical, also an ion channel for the Na+. this allows the ion to depolarise the post synaptic cell.

Question 17

Post synaptic density

Answer 17

the membrane appears thick because it is filled with the receptors