Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Neuro200 > Quiz 2 > Flashcards

Quiz 2 Flashcards

1
Q

What triggers Action Potential?

A

Opening of Na+ channels
Moving closer to 0
Depolarization stimulus
Graded potential

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

Role of voltage gated Na+ channels in Action Potentials?

A

Generation and propagation
Difference in concentration

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

Role of voltage gated K+ channels in Action Potentials?

A

Repolarization!

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

Positive Feedback:

A

cycle of rapid membrane depolarization during the action potential where initial change triggers response that creates a loop that accelerates process.
Inward flow of Na+ -> Depolarization -> Open voltage gates Na+ channels -> REPEAT ->

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

Action Potential Generation

A

depolarization, opening sodium channels, more sodium = more depolarization

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

Breaking (+) Feedback Loop:

A

Inactivation of Na+ channels or open of K+ channels

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

What makes action potential more likely to be initiated at axon hillock?

A

Proteins such as, high density of voltage gated Na+ channels at Axon Hillock; therefore more depolarizing

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

What would happen if K+ channels and Na+ channels open at the same time?

A

Not much change in membrane potential’ no action potential.

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

K+ channels are already slow, what would happen if they were even slower?

A

The depolarizing phase would be longer and deylaed repolarization
(Normally, the K⁺ efflux (outflow) helps bring the membrane potential back to its resting negative value after the peak of the action potential. If these channels were slower, K⁺ would leave the cell more gradually, meaning the cell would stay more positive for a longer period.
This would prolong the depolarized state of the neuron, making the membrane potential stay near or above 0 mV for a longer time.)

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

Absolute Refractory Period:

A

Na+ are open, inactive and cant open again. Cannot fire another action potential.

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

Relative Refractory Period:

A

K+ channels slow to close. The neuron can fire another action potential, but only if the stimulus is stronger than normal. Cause Hyperpolarization -> resting potential. All-or-Nothing.

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

Saltatory Conduction:

A

Nodes of Ranvier cause another inrushing of sodium and regeneration of action potential. THis causes it to seem as if it is “jumping down” the axon.

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

Threshold:

A

When threshold is reached, a large number of Na+ channels open.

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

Hyperpolarization

A

AKA, refractory period, very difficult for neuron to fire again.

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

Characteristics of Graded Potential

A

Local change in response to stimulus. If change isn’t big enough to reach threshold. IPSP OR EPSP.
- can reach threshold if strong enough stimuli, then becomes AP
- can be summated, station or temporal to reach threshold, then becomes AP
- doesnt obey all-or-nothing law

Action potential is opposite of this!
Both changes in membrane potential!

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

Summation:

A

effects on stimuli on membrane potential can be additive. Synaptic inputs (excitatory or inhibitory) combine to influence membrane potential, determines if reaches threshold and fires action potential.

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

EPSP

A

Excitatory Post Synaptic Potential: temporary depolarization, more likely to fire action potential.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

IPSP

A

Inhibitory Post Synaptic Potential: temporary hyperpolarization, less likely to fire action potential

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

Which factor is responsible for preventing the action potential from going backward down the axon?

A

Inactivated sodium channels
The inactivated sodium channels prevent the membrane from depolarizing again

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

What triggers the voltage-gated potassium channels to open?

A

Peak

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

During the rising phase of the action potential, the membrane potential moves from -65 mV toward 0 mV. Does this change represent an increase or decrease in the membrane potential?

A

Since the membrane potential is the difference in electrical charge across the membrane, when the value moves toward 0, it indicates there is a smaller difference between the inside and outside of the neuron. The potential (the difference) is decreasing.

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

When is (+) feedback loop terminated?

A

When membrane potential reaches threshold (Na+ close and K+ open), allowing repolarization!

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

Refractory:

A

refractory period is a period of time after an action potential during which a neuron is either unable to fire another action potential or requires a much stronger stimulus to do so. It ensures that action potentials move in one direction along the axon and that the neuron has time to reset before it can fire again. (absolute and relative)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Factors determining Conduction Velocity:

A

Axon Diameter: larger diameter, icrease conduction velocity/speed
Myelination: presence of myelination, increased CV.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Nerve impulse and action potential
an action potential is the electrical signal that travels along a neuron, while a nerve impulse refers to the broader process of signal transmission, which includes the action potential and other steps involved in communication between neurons.
26
What creates (+) feedback loop?
During rising phase, membrane potential becomes more (+), more voltage gated Na+ channels open, allowing even dore sodium to enter cell.
27
What determines conduction velocity?
axon diameter: larger=faster myelination: prescence = faster
28
describe 3 synapses formed by neuron
Electrical: electrical current flows directly from one cell to the next, built for speed! Change in post synaptic membrane is immediate. Chemical: Chemical released by presynaptic neuron affects membrane potential of post synaptic neuron. Neuromuscular: chemical synapses between neurons and skeletal muscle
29
which synapse has cytoplasmic continuity?
electrical
30
continuity in electrical synapse is falicitated by...
gap junction channels
31
what is a gap junction channel made of?
one gap junction is made of 2 connexons that are embedded in membrane. 1 gap junction made of two connexons, made of 12 connexins
32
what makes the electrical synapse bidirectional?
continous cytoplasm, based on electrochemical gradients, however some can only be unidirectional,
33
what causes no delay from pre->postsynaptic cell in electrical synapse
cytoplasmic continuity
34
ionotropic receptors
Electrical and chemical. Na+ k+ and cl-. Rapid changes in membrane potential. ligand-gated ion channels (AKA chemically gated ion channel )
35
Metabotropic receptors
Only chemical because they do not conduct ions. Slower but more prolonged affects. associated with G protiens -> lead to changes in postsynaptic cell (2nd messenger cascades, biochemical changes)
36
what are G proteins
molecular switch;similar to shuttle, initiates cascade transmit extracellular molecules-> intracellular pathways. Requires multiple steps therefore longer process but lasting effects
37
where are ionotropic and metabotropic receptors found?
Chemical post synaptic membrane
38
Autoreceptors
located in presynaptic neuron; feedback mechanism (inhibit further release of NTs) mostly metamorphic
39
Which synapse can amplify signal and modulate
Chemical. Electrical cannot amplify- just transfer!
40
How is the ionotropic receptor opened
EPSP(NA+) /IPSP(K+) opens in response to NT binding for ion movement
41
how is G-proein ion channel activated
NT diffuses across synapse, binds to receptor, G protein is activated, G protein activated G protein ion channel (allowing ion to flow - EPSP/IPSP)
42
How is enzyme associated with G protein
When NT binds to receptor, G protein is activated, Enzyme is activated (2nd messengers are produced)
43
Which synapse is responsible for synthesis storage, release of NT
chemical. NT are synthesized and stored in vesiceles
44
what is it called when NT are released into synaptic cleft
exocytosis
45
types of synapse communication
axosomatic, axoaxonix, dendrodendritic
46
2nd messengers affect...
Cellular signaling by mediating affect of external signals (NT) that bind to cell receptors. Amplify signal inside cell. genes, proteins, activity of ion channels Small molecules inside cell that relay signals from cell surface receptors(G proteins)Second messengers amplify, propagate/speed up signals because one receptor can activate multiple G proteins, leading to the production of thousands of second messenger molecules
47
Graded potential
type of electrical signal, it is directly porportional magnitude (strength) of stimulus. Play critical role in inhibition of action potential.
48
Ionotropic directly control _________, metabotropic activate intercellular proteins via _____________.
ion channels; G Proteins
49
SNARE proteins
assist with vesicle trafficking, vesicle fusion.
50
2 types of SNARE proteins locations
Vesicle membrane (V-SNARES) and target membrane (T-membrane)
51
How do V and T proteins release into target area (synaptic cleft)
interaction between T and V proteins forms a complex that "snaps" V and T membranes together.
52
Small and large NTs
small neurotransmitters are rapid and involved in more immediate communication, while large neurotransmitters influence longer-term, more complex processes
53
How can a single NT have different effects in different tissues?
NT can have varying effects depending on which receptor it binds to.
54
Acetocholine
other NT, autonomic process, slow things down, ionotropic mostly, and metabotropic receptor, enzymatic degragation.
55
Dopamine
(monoamines) (synthesized from tyrasine), metabotropic receptor, selective reuptake transporters, pleasure and mood
56
monoamino acid
NT derived from amino acid, enzymatic modification
57
norepinephrene
(monoamine, tyrasine), metabotropic, selective reuptake (will only reuptake noepinephrene), stress/fight or flight
58
epinephrene
(monoamine, tyrasine), metabotropic, selective reuptake, adrenaline
59
seretonin
amino acid (tyrptophen), metabotropic, selective reuptake, mood, sleep, apetite
60
glutamate
EXCITATORY!!!!!!! amino acid, mainly ionotropic, some metabotropic, selective reuptake by presynaptic and glial cells.
61
GABA
inhibitory XXX, amino acid, ionotropic and metabotropic, selective reuptake by presynaptic and glial cells.
62
Ionotrpic = ____ channels, metabotropic open ___ channels.
Ionotropic = cl-,na+(inhibitory/excitatory) Metabotropic = opening of K+
63
large NT (petides)ertime
excitatory or inhibitory also act as modulators! neuropeptides, metabotropic, diffusion and enzymatic degragation
64
ATP
other/ "atypical", ionotropic or metabotropic, enzymatic degragation
65
endocannabinods
inhibitory (decrease release of NT from presynaptic neuron), retrograde signaling, other NT, metabotropic, glial cell/degragation
66
Gaseous transmitters
retrograde signaling, other NT, metabotropic, excitatory or inhibitroy, diffusion
67
LO: Explain the difference between “hyperpolarization” and “depolarization” of a membrane and explain how these relate to movement of sodium and potassium ions across the membrane. (Also know what is meant by an EPSP and an IPSP, and how these relate to these conditions).
hyperpolarization- gets more negative, efflux of k+ or influx of cl- move into cell Depolarization- gets more positive than resting potential, Na+ channels open, inside more (+) than outside EPSP- excitatory, (AP more likely), influx of Na+, DEPOLARIZATION IPSP- inhibitory, efflux of k+, inc=flux of cl-, (AP less likely), HYPERPOLARIZATION
68
LO: Describe the difference between a graded potential and an action potential and explain the role of summation in membrane potentials.
Graded potential: small changes in membrane potential (EPSP, IPSP) Action potential: large, all-or-nothing down axon (hyperpolarization, depolarization) Summation: Key in determining whether an AP will fire or not. (if it reaches threshold or not) Process in which graded potetntials combine, allowing for stronger depolarization. Spatial summation adds signals from different locations. Temporal summation adds from the same location overtime.
69
LO: Explain the role of voltage-gated sodium channels and voltage-gated potassium channels in the action potential (understand the timing of opening and inactivation/ closing, and the direction of ion flow through these channels when open.)
Voltage gated Na+ channels: will open to depolarize to reach threshold; this causes massive influx of Na+ ions, reaches peak where they are inactivated. Voltage gated K+ channels: Repolarizes, as membrane potential reaches peak, K+ channels slowly flow out of cell back to resting state.
70
LO: Describe the major events of an action potential.
Resting potential > Depolarization > Threshold > Peak > REPOLARIZATION> Threshold > Resting Potential > Undershoot > Resting Potential
71
LO: Recognize the difference between a nerve impulse and an action potential.
Nerve impulse: Result of sequential generation of action potentials, continuous signal, can travel long distances Action Potential: Caused by change in membrane potential, individual event caused by threshold, only along axon
72
LO: Explain what is meant by anterograde conduction and explain what accounts for anterograde conduction of nerve impulses.
anterograde: forward movement of nerve impulses down axon What accounts? propagration of action potentials and movement of ions across membrane.
73
LO: Explain how information about the intensity of a stimulus is conveyed, given that an action potential is an all-or-none response.
Stronger stimulus = AP at higher frequency Larger diameter=faster AP (stronger stimulus)
74
LO: Articulate how the action potential would be modified in the presence of a neurotoxin if the mechanism by which that neurotoxin acts is described.
Blocks or inhibits, takes longer for channels to close
75
LO: Describe factors that determine the conduction velocity of action potentials along an axon.
Axon Diameter, Myelination
76
LO: Define saltatory conduction and explain how it is achieved by myelination of axons.
saltatory conduction is "jumping node to node", myelin speeds up transmission
77
LO: Define positive feedback and describe how positive feedback affects the rising phase of the action potential.
Positive feedback: process in which the output or response of a system enhances or amplifies the initial stimulus. Contributes to rising phase because when initial depolarizing stimuli is amplified, more na+ channels open, therefore continuously enhancing stimulus, leading to a more depolarized membrane until it reaches its peak.
78
LO: Define and describe the absolute and relative refractory periods for voltage-gated ion channels.
Absolute: CANNOT fire AP, Na+ inactivated cannot open again Relative: can fire from stronger-than normal stimulus, K+ open
79
LO: Explain what makes the axon hillock a likely place for initiation of action potentials
axon hillock has high density of na+ channels
80
how does the refractory period prevents retrograde transmission of nerve impulses
cannot go backwards because can only be in antergrade. this is because na+ channels are closed and cannot lead to AP.
81
how NT gated ion channels could leaf to either EPSP or IPSP
depolarizing (EPSP=depolarizing) or (IPSP=hyperpolarizing)
82
Temporal summation
2 stimulus that add up to reach threshold in same area
83
Spatial summation
2 stimuli at different locations add up to reach threshold

Neuro200 (3 decks)

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