Brainscape's Knowledge GenomeTM

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


See full index

Cellular And Molecular > Lecture 4 - Integration At The Level Of Neuron > Flashcards

Lecture 4 - Integration At The Level Of Neuron Flashcards

1
Q

What is the importance of threshold?

A 
Action potential (nerve impulses) are all-or-none events 
Action potentials are regenerative and are propagated over long distances 
Action potentials are the currency of information transmission throughout the nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the stereotypical impulse properties a reminiscent of?

A

Transistor-transistor-logic (TTL) pulse

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

What does action potential frequency encode?

A

Intensity

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

How can intensity of a sensation be encoded by?

A

Variable action potential frequency

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

What did Baker et al do?

A

Sensory neuron in a dish
Inject current pulses that depolarises the membrane
As the depolarising current stand increases, incrementally increasing depolarising sub-threshold response

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

How can threshold change?

A

Second messenger pathway (G-protein)

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

What can protein kinase control?

A

The functional effect of one sub type sodium channel

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

What are the two ways of measuring threshold?

A

Current threshold

Voltage threshold

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

What is current threshold?

A

How much current needs to be applied to activate a neuron/axon and induce an action potential

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

What is voltage-threshold?

A

By how much does the membrane potential of a neuron have to change from rest to elicit an action potential

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

What is threshold-tracking in frog nerve?

A

Continuous measure of how excitable an axon is

Test the threshold repeatedly

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

What did Raymond design?

A

An electric box to alter the duration of the current he was applying to a single frog axon

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

What was measured as a single function of the impulse activity in the fibre?

A

The firing thresholds of a single myelinated fibres of frog sciatic nerves

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

What does conduction velocities range from and what does consist of ?

A

Ranged from 3-30 m/sec

Consisted of myelinated axons

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

What was the temperature, current strength and conduction velocity of a overnight tracking of threshold of a fibre?

A

Temperature: 18.5
Current strength: 0.4Ma
Conduction velocity: 14.7 m/sec

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

How do you get another action potential in the nerve?

A

Longer stimulus

More charge

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

What happens when there is more charge present?

A

More current is required to initiate action potential because sodium channels inactivate

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

What is H1 sub excitability caused by?

A

Activation of kinetically slow K+ channel in the node of Ranvier

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

In humans, what does a period of super excitability mean?

A

There is DAP in the axons

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

What contributes to refractory period?

A

Fast K+ channels
Makes axons less excitable when open
Hyperpolarising membrane

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

What are the two ways that sodium channel gates?

A

In a mode which gives rise to:
Transient current
Persistent current

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

What can persistent current be blocked by?

A

TTX

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

What can channels that gate persistently activate?

A

Negative potential transient current

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

What can persistent currents be involved in?

A

Controlling thresholds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is latent addition?

A

Applying brief hyperpolarising pulse to sensory/motor axons to see the effects this has on excitability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is threshold tracking?

A

Test nerve excitability which depends on the membrane properties of axons at site of stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Latent addition

A

Brief hyperpolarising current
Axons less excitable
Excitability returns to normal

28
Q

Motor axons

A

Exponential return to normal excitability

Passive properties of the axon

29
Q

Sensory axons in people are more … than motor axons

A

Excitable

30
Q

What is required to depolarise the neuron before GTP Gamma S goes in?

A

100pA

31
Q

Where is ATP placed?

A

Outside of the neuron

32
Q

What can ATP activate?

A

G-protein kinase receptors

33
Q

How do you get a functional upregulation of Nav1.9?

A

If small ion of a sensory neuron is exposed to ATP

34
Q

What happens when GTP Gamma S is placed inside neuron?

A

There is no large change in threshold

35
Q

What is spatial summation?

A

Simultaneous inputs at different points upon dendritic tree

Eliciting an action potential in a neuron with input from multiple presynaptic cells

36
Q

What can synapses give rise to?

A

Excitatory and inhibitory events in the postsynaptic cells

37
Q

What is temporal summation?

A

One presynaptic neuron releases neurotransmitter many times over a period

38
Q

Spatial summation

A

With respect to space

39
Q

Temporal summation

A

With respect to time

40
Q

Where does impulse initiation in neuron occur?

A

Initial segment at the sensory ending

41
Q

What confers high excitability?

A

High density of Na+ channels

42
Q

Somatic synapses would be expected to be stronger than what?

A

Those on distal dendrites

43
Q

How can Membranes be explained in terms of?

A

Series of electronic elements that contain resolution and capacitors

44
Q

What is Cable Theory?

A

Understand how electrical signals are affected by the properties of the cable

45
Q

Cable structures

A

Applicable to axons and dendrites in neurons

46
Q

A broader spine

A

More current flow

47
Q

Less resistance to current flow than an axon

A

Faster conduction velocity

48
Q

Where does la afferent carry information from?

A

Periphery (sensory nerve) into spinal cord making a synapse into the motor neuron

49
Q

What makes a synaptic contact on motor neuron?

A

3 la afferent

Multiple connections for each axon

50
Q

How does neurons integrate synaptic inputs over?

A

Dendritic fields (space) and over time

51
Q

What does cable theory explain?

A

Epps initiates further away from the initial segment will have slow rise-times and amplitudes at the soma

52
Q

What are dendritic spines thought to modify?

A

How important a synapse is by limiting current flow

53
Q

What are K+ current activated in response to?

A

Membrane depolarisation - delayed rectification

54
Q

What does K+ current incorporate?

A

Permenantly charged amino acids that can respond to changes in membrane potential by translocating and altering the polypeptide conformation

55
Q

What did this cable theory explain?

A

EPSP imitated farther away from initial segment, will have slower rise time and amplitude at the soma

56
Q

What does dendritic spine modify?

A

How important a synapse is by limiting current flow

57
Q

What does delayed rectifier channel restrict?

A

Duration of the nerve impulse and participate in regulation of repetitive firing of neuron

58
Q

Why was the K channel of axon given the name “delayed rectifier”

A

It changes the membrane conductance with a delay after a voltage step

59
Q

What can you do with K channel

A

Regulate pace make potential
Generate burst of action potential
Make long plateus in action potential
Regulate the overall excitability of cell

60
Q

What is the role of K channel?

A

Set the resting potential
Keep fast action potential short
Terminate period of intense activity
Lower effectiveness of excitatory inputs on a cell

61
Q

What does potassium channel incorporate?

A

Permanently charged amino acid that can respond to changes in membrane potential by translocating and altering the polypeptide conformation

62
Q

What can potassium channel contribute to?

A

Depolarisation of AP

Control repetitive firing

63
Q

When does potassium current inactivate?

A

Over a longer time base

64
Q

Voltage gated potassium channel

A

Activate in response to depolarisation
Undergo inactivation process
Participate in action potential repolarisation in neurons
Contribute to refractoriness and accommodation

65
Q

What is the current generated called where inactivation kinetics are rapid?

A

A current

66
Q

What can A current enable?

A

Pacemaker potential

Slow repetitive firing

Cellular And Molecular (9 decks)

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