Brainscape's Knowledge GenomeTM

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


See full index

Animal Physiology > Action potentials I & II > Flashcards

Action potentials I & II Flashcards

1
Q

Most common type of Neuron?

A

Multipolar neuron

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

Structure of Neuron:
Large central area?

A

Cell body or soma, contains nucleus and most organelles

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

Structure of Neuron:
Numerous short projections from cell body?

A

Dendrites

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

Structure of Neuron:
One long projection?

A

Axon

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

Structure of Neuron:
Location on cell body where axon connects is

A

Axon Hillock

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

Structure of Neuron:
Portion of axon that connects to axon hillock is

A

Initial Segment or spike initiation zone

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

Structure of Neuron:
Axons branch out at the ends, these ends are called

A

terminal branches

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

Structure of Neuron:
Terminal branches end in small swelling bulbs called

A

Axon terminal or presynaptic terminal.

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

Structure of Neuron:
Myelin sheath are made of _______ cells

A

Glial cells

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

Structure of Neuron:
Myelin sheath is interupted at intervals by gaps called

A

Nodes of Ranvier

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

What are graded potentials?
Where are they produced?
What is their function in neurons?

A

-Graded potentials are small changes in membrane potential AKA postsynaptic potentials.
-Produced on the dendrites, can also be from cell body.
-They regulate action potential production at the initial segment

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

Where are action potentials produced?
What is their function?

A

-Produced at initial segment
-They stimulate the release of neurotransmitters by propagating along the axon to each axon terminal.

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

Other names for:
-Cell body
-Graded potential
-Presynaptic terminal
-Spike initiation zone

A

-Soma
-Postsynaptic potential
-Axon terminal
-Initial segment

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

3 Characteristics of Action Potentials (AP):

A

-Every AP produced is IDENTICAL
-AP have an ALL-OR-NONE RESPONSE to a stimulus
-AP are TRANSMITTED WITHOUT DECREMENT

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

Depolarization:

A

Change in membrane potential to a less negative value than resting potential.

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

Hyperpolarization:

A

Change in membrane potential from a depolarized state.

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

What is needed to reach the threshold?

A

A depolarization.

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

Repolarization:

A

Return to resting potential from a depolarized state.

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

Typical resting potential for a neuron

A

-70 mV (milliVolts)

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

Threshold potential.

A

-55mv.

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

Depolarization:

A

Stimulates action potential
Results in an increase in sodium ion permeability.

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

Hyperpolarization:

A

Inhibits action potential

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

Types of Depolarization stimuli?

A

Threshold Stimulus
Sub-threshold Stimulus
Suprathreshold Stimulus

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

Threshold potential:

A

The membrane potential at which occurrence of the action potential is inevitable.

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

Threshold Stimulus:

A

The minimum depolarization needed to induce an action potential, when the membrane is at resting potential.

26
Q

Sub-threshold Stimulus:

A

Cannot induce an action potential because it is less than the threshold.
Less than +15mv.

27
Q

Suprathreshold Stimulus:

A

A depolarization above the threshold. Geater than 15mv.

28
Q

What amount of depolarization is typically needed to reach threshold?

A

+15 mV depolarization

If resting potential is -70 mV (typical) then threshold potential is -55 mV (-70 mV + 15 mV = -55 mV)

29
Q

Name 3 phases of action potential:

A

-Depolarization phase
-Repolarization phase
-Undershoot phase

30
Q

How much mv is needed to go from resting potential to threshold potential?

A

+15mv.

31
Q

Alternate names for depolarization phase

A

-Rapid depolarization phase
-Rising phase

32
Q

Alternate name for repolarization phase

A

-Falling phase

33
Q

Alternate names for undershoot phase

A

-Hyperpolarizing after potential
-After hyperpolarization phase

34
Q

What can induce an action potential when the cell is at resting potential?

A

A threshold and superthreshold stimuli.

35
Q

Membrane potential during depolarization phase (phase 1)

A

Depolarizes from threshold (-55 mV) to +30 mV

36
Q

Membrane potential during repolarization phase (phase 2)

A

Changes from +30 mV to -70 mV

37
Q

Membrane potential during undershoot phase (phase 3)

A

Is slightly hyperpolarized (less than -70 mV)

38
Q

Na+ Channels can open ______

A

In response to a depolarization to any change in membrane potential.
The higher the strength of depolarization the higher the chance of opening.

39
Q

When does Na+ permeability exceed K+ permeability?

A

At threshold.
This is due to leak channels.

40
Q

Conductance:

A

Local changes in membrane permeability to Na+ & K+ that induce and maintain action potential.

41
Q

What starts the Hodgkin cycle?

A

When Na+ permeability exceeds that of k+.
It is a positive feedback loop.

42
Q

The Hodgkin cycle is terminated by

A

The closing of the inactivation gate.

43
Q

What causes conductance to occur?

A

Opening and closing of voltage-gated ion channels within membrane.

44
Q

Another name for depolarization?

A

Rising Phase.

45
Q

Ion channels:

A

small pores in the membrane that are created by specialized membrane proteins.

46
Q

Inactivations state:

A

Activation gate opens, Inactivation gate is closed.

47
Q

Another name for repolarization:

A

Falling Phase

48
Q

Specificity in ion channels mean:

A

only certain ions can move through particular ion channels.

49
Q

Ungated ion channels:

A

always open AKA leak channels

50
Q

Undershoot:

A

A slight Hyperpolarization.
K+ channels close slowly.

51
Q

Potassium ion leak channels:

A

Responsible for increased permeability of K+ at resting potential.

52
Q

Gated ion channels:

A

Can be opened and closed in response to stimulis.

53
Q

Changes in permeability are called?

A

Conductance.

54
Q

Voltage-gated ion channels:

A

open and close in response to changes in membrane potential

55
Q

Refractory period:

A

The initial segment is less important than another stimulus during an action potential.
Reduced responsiveness to stimuli during the action potential.

56
Q

Phases of the refractory periods:

A

Absolute refractory
Relative refractory

57
Q

Absolute refractory period:

A

Begins @ threshold, and ends at the repolarization phase.
The membrane cannot respond to another stimulus.

58
Q

Relative refractory period:

A

Begins at the end repolarization phase and ends in undershoot.

59
Q

What is required for an action potential in a relative refractory period?

A

A superthreshold.

60
Q

What type of cells are in myeline sheets?

A

Shawn cells.

Animal Physiology (12 decks)

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