Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Neuroscience > Channels and Transporters Lec04 > Flashcards

Channels and Transporters Lec04 Flashcards

(62 cards)

Start Studying
1
Q

what 3 things did hodgkin and huxleys voltage clamp experiement predict?

A
  1. sepearete na and k channels
  2. voltage sensors in channels
  3. high conductance of channels to specific ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what happens once the patch clampvoltage reaches + 52 mv

A

early inward Na current is missing

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

what happens once the patch clampvoltage reaches + 65+ mv

A

early inward Na reverses to outward instead of inward

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

outward K current increases in magnitudie as the the voltage becomes more

A

positive

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

patch clamp technieque records

A

microscopic currents (current flowing through a single membrane channel due to depolarization)

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

what are macroscopic currents due to?

A

current flow through may channels

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

what did patch clamp recording show?

A

provided evidence for single channels

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

in channels, there is a fast switch between

A

open and close states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In response to depolarizing effect from the pipette, single channels open and close in a ____ fashion

A

_ all or none_ fashion that is random or stochastic in nature

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

what does the probability of opening a channel depend on?

A

the stimulus

depolarization increases the proability a channel will be opened

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

what is gating? what does it involve?

A

gating is the transition between open and closed states

involves a temporary conformational change in the channels structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does macroscropic current arise from?

A

the aggregate effects of THOUSANDS of microscopic currents

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

there is a close correlation of the____ of macroscopic and the sum of many trials of microscopic currents

A

time course

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

what is different about K channel and Na channel properties?

A

K channels have longer latency time and longer duration

also obviously different dierection

(Na on left, K on right)

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

on average the K+ channels tend to be an ____ state while the membrane is depolarized

A

open state (this results in a more sustained response)

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

most cns neurons ahve multiple ___ channels with different characteristics

A

potassium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

charactersitics that vary with K channels

A
  1. low voltage vs. high voltage activation (voltage dependence)
  2. how fast the population reaches maximum conductance (rate of activation)
  3. how fast they inactivate (some dont even inactivate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is important about the varying rates of K channel inactivation

A

inactivation properties

produce a diversity of spike waveforms and spike patterns for different cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Fast AHP ____ action potential

A

shortens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

FAST AHP involves ___ repolarization

A

fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

when does fast AHP affect the early spike frequency

A

at very high frequencies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does medium AHP control

A

controls early interspike interval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does medium AHP control

A
  1. early spike frequency adaption (slowly activating by Ca entry)
  2. late spike frequency adaption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

BK K+ channels have ___ inactivation

A

fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
\_\_\_ and ___ are nonainactivating K channels
IK and SK
26
what do slow AHP do?
limits firing frequency by an unkwnon channels
27
order of channel activation
28
what is the order of K channel activation
1. Ka and Kdr channels first open 2. Kbk channels open 3/ other known and unknown K channels open
29
large number of ion channel genes create neurons with diverse \_\_\_
electrical properties
30
fast AHP occurs in ___ seconds
2-5 ms
31
medium AHP occurs in ___ seconds
10-100 ms
32
slow AHP occurs in ___ seconds
100-3000 ms
33
inactivation pattern of Kv2.1 channels?
show little inactivation
34
inactivation pattern of Kv4.1 channels?
inactivate rapdily after depolarization
35
when do inward rectifers allow more current flow?
during hyperpolarization
36
why do so many genes encode K+ channels?
activation, gating, inactivation
37
shape complex electrical responses influence
1. duration of AP 2. resting membrane potential
38
TheC a++ activated K+ channel opens in response to
increasedintracellularCa++ and sometimes to membrane depolarization.
39
the ___ of ion channels is key to developing new therapeutics for CNS disorders
diversity
40
what do channelpathies result from?
they happen due to mutations in channel genes
41
channelpathies in voltage gated Ca channels
congential stationary night blindness familial hemiplegic migraine episodic ataxia type 2
42
channelpathies in Na channels
generalized epilepsy with febrile seizures
43
channelpathies in K channels
benign familial neonatal convulsion
44
channelpathy that causes**_ congential stationary night blindness_**
Ca
45
channelpathy that causes**_ generalized epilepsy with febrile seizures_**
na
46
channelpathy that causes**_ familial hemiplegic migraine_**
Ca channel
47
channelpathy that causes **_benign familial neonatal convulsion_**
K
48
what toxins block Na channels?
ttx and saxitoxin
49
what toxins inactivate Na channels?
Batrachotoxin (frogs)
50
what does a-toxin do?
prolongs the duration of Na channels
51
what does b-toxins do?
shift voltage activation of Na channels
52
which toxins blod K channels?
apaminin (bees) and dendrotoxin (wasps)
53
what does TEA block?
K channels and AcH receptors
54
What blocks Ca channels?
ω-conotoxins (cone snails) and ω-agatoxin (spiders) block Ca channels
55
active ion transports work ___ a electrochemical gradient
against
56
how do active ion transporters and channels differ?
active ion transporters having slow binding and unbinding also are slower transport than channels
57
w-conotoxins blocks ___ channels
n type Ca
58
w-agatoxin blocks ___ channels
P/Q type Ca channels
59
\_\_\_\_ form a compelx with the ion they transport
active ion transporters
60
how do ion exchangers work?
they don't use energy but trade an intracellular ion for an extracellular one
61
how do ion co-transporters work?
transport two or more moelcules in the **_SAME DIRECTION ACROSS A MEMBRANE_**
62
methods in determining channel type?
1. patch clamp technique 2. gene cloning 3. x ray crsytallography

Neuroscience (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions