Channels

Question 1

____ channel

opens or closes by changes in membrane potential

Answer 1

voltage gated

Question 2

___ channel

opens or closes by hormones, 2nd messengers, NT

Answer 2

ligand gated

Question 3

skeletal muscle receptor Nm is and example of ___ channel

Answer 3

ligand-gated

Question 4

diffusion potential is generated across a membrane because of a concentration differences of ___

Answer 4

ions

Question 5

this balances the the tendency for diffusion caused by concentration difference

Answer 5

equilibrium potential

Question 6

The RMP of -70mV is caused by

Answer 6

1. Nerst potential for Na and K
2. K leak
3. NaK ATPase pump

Question 7

the nerve membrane more permeable to ___ (K or Na)

Answer 7

K

Question 8

Reduction of potassium leak out of the cell results to the ____ of the membrane potential

Answer 8

hyperpolarization

Question 9

Characteristics of a true action potential

Answer 9

1. Stereotypical size and shape
2. Propagating
3. All-or-none

Question 10

the propagation of action potential at one cell causes depolarization of the adjacent cell in a ___ manner

Answer 10

nondecremental

Question 11

All cells have ___ potential

Answer 11

resting membrane

Question 12

[repolarization/depolarization]

m gate open
h gate open

Answer 12

depolarization

Question 13

[repolarization/depolarization]

m gate open
h gate close

Answer 13

repolarization

Question 14

[repolarization/depolarization]

opening m gate facilitates entry of ___ (ion)

Answer 14

sodium

Question 15

[repolarization/depolarization]

opening of h gate facilitates entry of ____ (ion)

Answer 15

sodium

Question 16

[repolarization/depolarization]

opening of n gate facilitates entry ___ (ion)

Answer 16

potassium

Question 17

[repolarization/depolarization]

m gate close (Na)
h gate open (K)

Answer 17

repolarization

Question 18

[repolarization/depolarization]

m gate close
h gate open

Answer 18

at rest

Question 19

[repolarization/depolarization]

RMP more positive

Answer 19

depolarization

Question 20

[repolarization/depolarization]

RMP more negative

Answer 20

hyperpolarization

Question 21

[repolarization/depolarization]

positive charges flow towards the cell

Answer 21

depolarization

Question 22

[repolarization/depolarization]

positive charges from out of the cell

Answer 22

hyperpolarization

Question 23

[term] ____

net inward current > net outward current

Answer 23

threshold

Question 24

[term] ___

MP > 0mV

Answer 24

overshoot

Question 25

[term] ___

MP < RMP

Answer 25

undershoot

Question 26

In absolute refractory period, the Na-inactivation gates (m gates) are ____

Answer 26

closed

Question 27

[term] ___

occurs during an AP when no new AP can be elicited regardless of how large the stimulus is

Answer 27

ARP

Question 28

[term] ___

occurs during and AP AFTER ARP when new AP can be elicited but greater Na inward current is needed

Answer 28

RRP

Question 29

in RRP, thee opening of the K channels are ____ (short, long)

Answer 29

prolonged

Question 30

occurs when the cell membrane is depolarized but not rapidly enough causing Na-inactivation gate to eventually close

Answer 30

accommodation

Question 31

[upstroke/downstroke]

___ is seen during depolarization

Answer 31

upstroke

Question 32

Factors that increase conduction velocity

Answer 32

1. Fiber size
2. Nerve diameter
3. Myelination

Question 33

the AP is regenerated in ___

Answer 33

nodes of ranvier

Question 34

___ contains the highest concentration of Na channels per square micrometer of cell membrane

Answer 34

nodes of ranvier