Action Potential

Question 1

True or false
Action potential is a change in membrane potential resulting in
Repolarization followed by
Depolarization of membrane”

Answer 1

F

Question 2

Brief reversal of membrane potential
occurs with a total amplitude of

Answer 2

100 mv

Question 3

What are the Two types of channels involved
in action potential in a nerve
fiber

Answer 3

Voltage (k and na)

Question 4

True or false
Voltage potassium channels are present in smooth muscles

Answer 4

True

Question 5

Sodium and potassium channels Gates open or close in response
to a change in

Answer 5

Membrane potential i.e. voltage

Question 6

……is that level of membrane
potential [MP] at which action potential is
inevitable.

Answer 6

Threshold

Question 7

T or f
At threshold potential, net
inward current becomes larger than net
outward current

Answer 7

T

Question 8

True or false
In resting state , the membrane is more premeable to k+

Answer 8

True

Question 9

True or false
All Voltage-Gated Na+ and K+ channels are open

Answer 9

False

Question 10

What gate of na channel open in resting state

Answer 10

Inactivation

Question 11

What typa channel opena qhwn depolarization happen

Answer 11

Na channel(activation gates)

Question 12

Depolarization is due to ?

Answer 12

Opening v-g na channel

Question 13

At the end of depeloarization what gate of na channel closes

Answer 13

Inactivation gate

Question 14

True or false
During undershoot
Na+ tries to take mp to its equilibrium potential

Answer 14

F. Overshoot

Question 15

True or false
At the peak of AP, membrane is closest to Na+ equilibrium
potential

Answer 15

T

Question 16

What causes downstroke in graph?

Answer 16

Positive charges leaving cell

Question 17

Thus repolarization is caused by

Answer 17

an outward K+ current as well as stopping of Na+ influx

Question 18

True or false
Repolarization and k efflux restore the resting ionic
conditions

Answer 18

False.Repolarization and K efflux
restores the resting electrical
conditions of the neuron only

Question 19

Ionic redistribution back to
resting condition is restored by
the

Answer 19

sodium-potassium pump

Question 20

True or false
During Resting state more K+ leaking out, less Na+ leaking in

Answer 20

True

Question 21

Graded potential are produced by

Answer 21

Soma and dendrites

Question 22

Graded potentials are produced in dendrites and soma due to

Answer 22

Opening of ligand gated channels

Question 23

Action potential fires up at which region

Answer 23

in the region of initial segment rich in V-G Na+

Question 24

The transmission of a depolarization process along a nerve fiber is called

Answer 24

Nerve impulse

Question 25

When does voltage gated Ca++ channels open

Answer 25

When AP reaches axon terminal

Question 26

Speed of propagation depends on

Answer 26

Myelination Diameter كلهم علاقتهم طردية

Question 27

What type of impulse conducting is faster

Answer 27

Saltatory

Question 28

"The time period during which another normal AP can not be generated, no matter how strong is the stimulus. " This is a definition of?

Answer 28

Shows refractiry period

Question 29

Whats this Diffention Time from the opening of the Na+ activation gates (threshold) followed by closure of inactivation gates that enter a closed, inactive state.

Answer 29

Absolute refractory period

Question 30

True or false In relative refactory period k+ gates are open and repolarization is occuring

Answer 30

True

Question 31

Why in the relative refactory pitiontal the supra-threshold stimuli can open Na channels to cause AP

Answer 31

Cause The threshold level is elevated

Question 32

the magnitude of ap is dependent upon

Answer 32

1-serum Na+ level Refactory period

Question 33

True or false The action potential amplitude depends on strength

Answer 33

F. It follows all or none law

Question 34

I cardiac and smooth muscles what ions enter the cell to produce depolarization

Answer 34

calcium

Question 35

Affect of hyperkalemia on membrane

Answer 35

depolarization c

Question 36

Hypokalemia affect on membrane

Answer 36

Hyperpolarizing

Question 37

What happens when ca binds to na

Answer 37

stabilize the electrical state of Na+ channels.

Question 38

Whats the cause behind muscle tetany

Answer 38

Hypocakcemia

Question 39

At the peak of AP, membrane is closest to ...... equilibrium potential

Answer 39

Na