Resting membane potential and acrion potential

Question 1

what does selective permemabiy of the membrane mean

Answer 1

it generates resting membrane poteintal

Question 2

what is the voltage charge across a cell membrane

Answer 2

-50 to -90

Question 3

what does the difference in ions across the plasma membrane result in>

Answer 3

generates RMP

Question 4

what does diffusion do in the memrbane?

Answer 4

establish membrane potential

Question 5

what does active t do in the membrane

Answer 5

maintains it

Question 6

describe the leaky boat example?

Answer 6

K+ leaks out, Na+ seeps in
Na+K+ pump bails Na+ out and K+ in
Rate of active transport =rate of Na+ diffusion

Question 7

why the changing of the rmp important?

Answer 7

Changes in RMP allow neurons to receive process & send information

Question 8

how does the rmp change?

Answer 8

Alteration of ion concentration
Alteration of membrane permeability

Question 9

describe a graded portential?

Answer 9

Usually incoming
Short distances
Variable strength

Question 10

Action Potentials describe?

Answer 10

Long distance
Same stregth

Question 11

what happens in depolarisation?

Answer 11

decrease in membrane potential
less negatvie
-70 to -65mv

Question 12

what happens in hypoerpolarisation?

Answer 12

increase in membrane potential and is more negative
-70 to -75

Question 13

what is a temporal summation?

Answer 13

rapid sucession of stimuli

Question 14

what is spatial summation?

Answer 14

differnet sources of stimuli

Question 15

what causes depolirsation?

Answer 15

sodium flowing into the cell

Question 16

what causes repolirsation?

Answer 16

caused by k+ flowing out of the cek

Question 17

what causes hyperpolirsation?

Answer 17

caused by k+ continiung to leave the cell

Question 18

what happens in rapid depolrisation?

Answer 18

voltage gates sodium and pottassium have activation gates

a stimuuus finally reaches it which cause the threshold to go to -55mv

the gates now open +ve feedback

Question 19

what happens in hypoerpolarisation?

Answer 19

increase in k+ permemability last longer than required

the sodium and potassium pump back to resting membrane potential

Question 20

what is the refactory period

Answer 20

time interval during and after an action potential when a neuron or muscle cell is temporarily unable to generate another action potential in response to a stimulus.

Question 21

what happens in an absolute rf

Answer 21

all sodium channels open or inactive

Question 22

what happens in a relative rf

Answer 22

increase threshld for an AP and a 2nd ap is potential

Question 23

Period of reduced excitability

Answer 23

during AP
immedialtey after AP

Question 24

what is the good thing about a RF

Answer 24

enforces one way tranmission of AP

Question 25

how do AP travel?

Answer 25

Na+ influx in specific region
Depolarisation of region
Adjacent current flow
VG-Na+ channels open in adjacent region

Question 26

explain the propagation of a non myelinated axon?

Answer 26

Na+ influx in specific region
Depolarisation of region
Adjacent current flow
VG-Na+ channels open in adjacent region

Process continues along entire length of axon
Self-propagating
Refractory period drives forward direction

Question 27

what does a myelinated popgation allow?

Answer 27

saltatoru conduction

Question 28

graded potentials are …

Answer 28

Graded potentials are below the subthreshold but can summate to initiate action potentials.