Nervous System Pt.1 Depolarization

Question 1

Depolarization

Answer 1

when a cell is STIMULATED, there is a reversal of the resting-membrane potential

Question 2

1st step in depolariationL:

Answer 2

the sodium channels in the dendrite OPEN-

sodium goes down concentration gradient from the ECF to the ICF

Question 3

the inflow of the sodium ions produces:

Answer 3

a small current that travels from the dendrite to the cell body

the current goes to the AXON Hillock and a build-up of electrical current builds up

Question 4

Threshold

Answer 4

when the electrical potential builds up to a certain point the AXON HILLOCK will OPEN and cause more NA ions to come in for further DEPOLARIZATION

Question 5

End result:

Answer 5

ICF and ECF change polarity

ICF Iis postive

ECF is negative

Question 6

Action Potential:

Answer 6

the rapid-shift in electrical potential

cell membrane is now active

Question 7

When a cetain threshold is reached at the axon hillock:

Answer 7

the sodium ions enter the AXON and action potential occurs at a short distance along the axon

Triggers new action potential just ahead of it, opens more NA channels

Question 8

Define Threshold:

Answer 8

the minium electric potential needed to trigger action potential

Question 9

Action potentials are ALL OR NONE:

Answer 9

once the threshold is reached, an action potential is triggered and cannot be stopped