RMP

Question 1

Define rmp

Answer 1

the pd between the inside and outside of a cell that isn’t stimulated into action

Question 2

Rmp for 
Smooth muscle
Skeletal muscle
Cardiac muscle
Nerve cell

Answer 2

• 50mV(unstable)(-30to-55)
• 90mV
• 90mV
• 70mV

Question 3

ICF

Proton or no proton
Electron or no electron
Alkaline or acidic

Answer 3

Proton free
Electron free
Alkaline

Question 4

Ionic ways to fat RMP

Answer 4

K efflux(major contributor)
Na/k Atpase( less contributor)
Cl influx (least contributor)

Question 5

Why is Cl influx not contributing much to the Rmp generation

Answer 5

Cl influx contributes very little because of the repulsion effect

Question 6

Why isn’t Na influx making much of a difference

Answer 6

because it’s not as fast. K is 100 times more permeable

Question 7

Equilibrium potential of ions

Answer 7

When the rate of leaving is equal to coming in

Question 8

Rmp of a large neurone = E_
Rmp of a small neurone= E_
Rmp of cardiac muscle = E_

Answer 8

Ek
Ecl
Ek

Question 9

Equation to measure rmp is?

Answer 9

Nernst Goldman’s equation

Question 10

A strength -duration curve plots - against -

Answer 10

Intensity on Y

Time on X

Question 11

AP or no-AP 
Subthreshold for extended time 
Subthreshold for the right time 
Subthreshold for a short time
Threshold for a short time
Threshold for extended time
Threshold for right time
Suprthreshold for short time
Supra threshold for right time

Answer 11

No
No
No
No 
Yes
Yes
No
Yes

Question 12

Stimulus intensity is also called-

Stimulus duration is also called-

Answer 12

Rheobase

Utilization time

Question 13

Index of excitability is -

Answer 13

Chronaxie

Question 14

Chronaxie is measured in ?

Answer 14

Time (s)

Question 15

High chronaxie values means?

Answer 15

The stuff isn’t very excitable

Question 16

Which stimulus produces local response/electrotonic potentials

Answer 16

Subthreshold stimulus

Question 17

Nerve cell can be fatigued

T/F

Answer 17

F. It can’t be fatigued

A transmission process can be fatigued tho

Question 18

How to fix a fatigued transmission?

Answer 18

Make the cell rehogenic

Question 19

Temporal and spatial summation

Define

Answer 19

Temporal:succession(common in pns)
Spatial:simultaneous (common in cns)

Question 20

Range of absolute refractory period

Answer 20

From start of depolarization to 1/3 of repolarization

Question 21

Duration of absolute refractory period in mammalian nerve

Answer 21

0.4-1msec

Question 22

Reason for Absolute refractory period

Answer 22

this is due to the sodium gates already being engaged and therefore unresponsive

Question 23

Range of relative refractory period

Answer 23

From 1/3 of repolarization to start of after-depolarization

Question 24

What type of stimulus can fire an AP during relative refractory period

Answer 24

Suprathreshold stimulus

Question 25

Why must the stimulus in RRP be Suprathreshold

Answer 25

because there are numerous activated K channels causing hyperpolarization

Question 26

Stimulus artifacts is produced by the nerve

Answer 26

F. It’s a product of human intervention

Question 27

Define latency period

Answer 27

Isopotential interval from artifact point to start of AP

Question 28

Effect of changing distance between recording and stimulating electrode on latency period

Answer 28

Increase distance, increase latency period which would reduce speed of conduction

Question 29

RMP can be measure with - | AP can be measured with - or -

Answer 29

Erm | IRM or erm

Question 30

Skeletal ,cardiac,nerve , smooth muscle | Arrange in order of decreasing spike duration

Answer 30

Cardiac 300msec Smooth 50msec Skeletal 2-5msec Nerve. 1msec

Question 31

Which is more prominent? | After depolarization or after hyperpolarization

Answer 31

After hyperpolarization

Question 32

Duration of the after potentials in a neurone

Answer 32

After depo- 4ms | After hyper-40ms

Question 33

Spike potential and after potential are independent of each other T/F

Answer 33

T. Change in one doesn’t affect the other

Question 34

In generating AP in a neuron, is the peak reached?

Answer 34

No. The peak is Ena (60mV) but it usually stops at 40mV due to sodium gates closing and repulsion (++)

Question 35

Duration of SA node AP

Answer 35

250msec

Question 36

Difference between SA node AP and cardiac AP

Answer 36

Initial depo is by rapid Ca not rapid Na | Pre potential is by slow Na gates

Question 37

How to maintain cardiac AP

Answer 37

By activity of Na/K atpase Z^3 If sodium doubles, Na/k activity increases by 8folds

Question 38

Mentions 3 waves that are imposed on rmp in smooth muscles

Answer 38

Spike, slow waves and pacemaker potentials

Question 39

Slow waves is independent of nerve supply | T/F

Answer 39

T. It’s by ENS

Question 40

Spikes can only occur during depo phase of slow waves

Answer 40

F. Can occur at any phase

Question 41

Spikes have variable peak potentials | T/F

Answer 41

T

Question 42

Excitation-contraction effect in smooth muscle

Answer 42

Slow Contraction starts 200ms after excitation (spike) Ends 150ms after spike is over Peak contraction is 500msec after spike starts

Question 43

excitation-contraction effect in cardiac and skeletal muscles

Answer 43

Less than 10msec

Question 44

SALTATORY and ELECTROTONIC Conduction of AP Myelination Movement

Answer 44

S: myelinated and jumps from node to nodes;dense Na channels at nodes and least at soma ; Na is flanked by K E: unmyelinated;must occur at every point of the nerve