Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHPY 301 > Lec 7 > Flashcards

Lec 7 Flashcards

1
Q

What is can be determined by “measuring the amplitude of an ionic current at a series of different voltages imposed on the cell using a voltage clamp “ ?

A

Voltage dependence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A Current - Voltage relationship shows the total amount of current flowing through all of the channel of a given type at each voltage

T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is defined as “voltages at which the current begins to appear” ?

A

Voltage Thresholds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define “inward/outward current” .

A

the direction that each ion flows at physiological voltages.

IE. Na has inflow current

IE. K+ has outflow current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is defined as “the voltage at which the Na+ current reverses direction” ?

A

reversing potential of Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When does the “flow” or current of an ion reverse?

A

When the membrane potential (Vm) is more positive than its threshold.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Whether an individual cahnnel is open or not can be predicted precisely using probabilities

T or F?

A

False:

CANNOT be predicted with certainty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What 2 events can increase the probability of a ion channel opening?

A
  1. Cell membrane voltage
  2. Concentration of a ligand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Total Conductance (G) will increase with the _______ (increases/decrease) of Voltage.

A

increase

G is proportionate to voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

As Po or the total number of open channels increases , the conductance will _______ (increase/decrease).

A

increase

Po is proportionate to g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What determines the amplitude of total cell current at each current?

1.

2.

A
  1. Number of cells that are open
  2. The current passing through each of them.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The more ______ (positive/negative) the charge, the more channels open.

This is based on which scientific theory?

A

positive

Ohm’s Law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The number of open channels (Po) depends on voltage

T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Current-Voltage relationships (similair to voltage clamp experiments) can be obtained by multiplying :

Total # of channels

x

single channel current

x

___________

(fill in the blank)

A

Probability of channel opening. (Po)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The probability of a ion channel being open depends on the membrane potential (Vm) _______ (increasing/decreasing) as the membrane is depolarized.

A

increasing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If Vm is decreasing then there is a _____ (inflow/outflow) of current. Which ion is most likely responsible?

A

inflow , Na+

17
Q

If the Vm is increasing then there must be a ______ (inflow/outflow) of current. The ion that is most likely responsible is?

A

outflow , K+

18
Q

Na+ channels have a separate _________ that K+ channels do not.

A

inactivation gate

19
Q

Both activation and inactivation are voltage dependent processes that occur when the membrane depolarizes

T or F?

A

True

20
Q

Na+ channel “activation gates” are ______

  • slower
  • faster

than its “inactivation gates” .

A

Faster

21
Q

Na+ inactivation gates can open and allow Na+ influx before the process of deactivation closes the channel.

T or F?

A

False:

Na+ activation channels can open and alllow Na+influx before the process of inacivation closes the channel.

22
Q

Probability-Voltage graphs are shown at steady state.

T or F?

A

True

23
Q

Define “steady state “

A

means it was measured at infinite time.

24
Q

What is defined as “opening of an inactivation gate”

A

recovery from inactivatoin

25
Q

What is defined as “closing fo an activation gate”

?

A

Deactivation

26
Q

Following an “action potential” (or hyperpolarization) the activation gates of both K+ and Na+ will _____ (open/close) and inactivation gates of Na+ channels will ______ (open/close).

A

activation gates close

inactivation gates open

27
Q

_________ (activation/inactivation) gates are responsible for the absolute refractory period.

A

inactivation

28
Q

During an action potential, Na+ channels undergo _______ (positive/negative) feedback, which in turn activates more Na+ channels and depolarizes the membrane more.

A

positive

29
Q

During an action potential K+ channels undergo ______ (positive/negative) feedback and repolarize the cell with the help of Na+’s inactivation gate!

A

negative

30
Q

opening of Na+ channels causes an _____ (slow or fast) depolarization toward ENa.

A

Fast

31
Q

Opening of K+ channels leads to ____ (slow/fast) repolarization towards EK.

A

slower

32
Q

Opening of Na+ channels shifts the permeability of the membrane in favor of PNa

T or F?

A

True

33
Q

The inactivation of Na+ channels helps shift the permeability back in favor of PK

T or F?

A

True

along with the activation of K+ channels

34
Q

The opening of K+ channels shifts permeability in favor of PNa.

T or F?

A

False

in favor of PK

35
Q

Na+ currents turn off while the membrane potential is still high because of ___________, where as K+ currents turn off because , as the membrane potential repolarizes the K+ channels deactivate.

A

inactivation

36
Q
A

PHPY 301 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions