Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology 224 > Theme 6 > Flashcards

Theme 6 Flashcards

Signal Transmission in the Nervous System

1
Q

Neurons use electrical signals to communicate with:

A

neurons
muscles
glands

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

electrical signals or nerve impulses involve changes in the amount of electrical charges across a cell’s plasma membrane. This is called:

A

Membrane Potentials

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

T of F: All cells have membrane potentials.

A

True. But only neurons, muscle, and endocrine cells are excitable.

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

what types of cells are excitable?

A

endocrine
muscle
neuron

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

Why do we study squid axons?

A

Squid giant axons are used extensively to study membrane potentials.

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

What is the diameter of a typical giant axon of a squid?

A

1mm

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

what is the function of the giant axon of a squid?

A

controls part of the water jet propulsion.

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

Is the giant axon of a squid myelinated or unmyelinated?

A

unmyelinated; which decreases the conduction velocity potential substantially.

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

What decreases the conduction velocity potential of a squid giant axon?

A

it being unmyelated.

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

Voltmeter does what?

A
  1. records the voltage difference between the micro electrodes inside and outside the neuron.
  2. measure of membrane potential
  3. measurement made as a function of time.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T or F: Neurons are electrically Polarized

A

True; outside of the membrane and inside of the membrane is polarized.

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

The positive and negative “poles” of a neuron are…

A

on the inside and outside of the cell membrane.

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

What acts as a barrier that separates the charges within a neuron?

A

the plasma membrane

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

The difference in charges on the inside and outside of a cell membrane act as :

A

an electrical force measured in volts.

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

T or F : The plasma membrane is permeable to cation and anions

A

False - impermeable to cations and anions.

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

plasma membrane of a Neuron functions as:

A
  1. separates charge (on inside and outside of cell)
  2. maintains resting potential within cell. (-70mV)
  3. Negative ions within the cell are drawn to the positive ions arrayed on the outside surface of the membrane.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The resting potential inside the cell:

A

-70mV

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

Which is more negative? The interior of the neuron cell membrane or the exterior?

A

interior cell membrane

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

What type of channels do Ions move through?

A

gated channels.

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

what are the two types of gated channels?

A

Voltage-gated

Ligand-gated

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

Voltage gated channel

A

open and close in response to voltage changes

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

ligand gated channels

A

open and close in response to ligands or chemicals.

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

What are the 3 membrane factors that contribute to resting potential?

A
  1. Na+/K+ -ATPase pump
  2. Ion channels
  3. Negatively charged molecules such as proteins more abundant inside the cell.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Na+/K+-ATPase pump

A

transports 3 Na+ out for every 2K+ moved in.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Do ion channels need energy?
No.
26
Two types of Ion channels that contribute to resting potential?
Na+ specific channels | K+ specific channels
27
Ion channels
allows passive movement of ions
28
Within a neuron cell membrane, there are more ungated channels of which type? K+ or Na+
more K+ ungated channels than Na+ ungated channels
29
Neural membrane is more permeable to which ion at rest? K+ or Na+?
K+
30
What are the 3 possible states of sodium channels?
1. Open 2. Closed 3. Inactive
31
There are more K+ or Na+ in the cell?
K+
32
There are more K+ or Na+ outside the cell?
Na+
33
Membrane potential
the difference between the electric charges inside and outside the cell.
34
Resting Potential
membrane potential of a cell that is not sending nerve impulses
35
Action potential
membrane potential of a cell that is sending nerve impulses
36
Electrochemical Gradient
combined effect of electrical and chemical gradients.
37
Depolarization
cell membrane less polarized, less negative relative to surrounding solution.
38
Hyper-polarization
cell membrane is more polarized, more negative.
39
Gated channels open allowing Na+ to flow in and membrane potential becomes more positive (less negative) this is an example of:
Depolarization
40
K+ moves out of the cell making the cell membrane less positive (more negative) This is an example of:
Hyperpolarization
41
Two types of Membrane Potentials:
1. graded potentials | 2. action potentials
42
Graded potentials
depolarization or hyperpolarization varies depending on strength of stimulus occur locally on dendrites or soma spreads a short distance and dies out act as triggers for action potential.
43
What type of membrane potential varies its polarization depending on the strength of stimulus?
Graded potentials
44
What type of membrane potential triggers for action potential?
graded potentials
45
Action potentials
``` carry the electrical signal along an axon always the large same amplitude of depolarization All or none response (can't be graded) Actively propagated(regenerates itself as it travels) ```
46
What type of membrane potential is actively propagated?
action potentials
47
what type of membrane potential always has the same large amplitude?
action potentials
48
Action potentials are generated by what type of ion channels?
voltage-gated ion channels
49
When do the voltage gated ion channels shut during an action potential within a neuron?
when the membrane potential is near the resting potential
50
What causes the voltage gated ion channels to initially open?
when membrane potential increases to a threshold value
51
Threshold potential
-50mV - barrier that initiates an action potential
52
which voltage-gated channel opens and triggers action potential?
Na+ channels
53
Which Ion diffusion into the cell causes the "spike" in an action potential?
Na+
54
What happens when an action potential reaches its "spike" and the membrane is sufficiently positively polarized?
the Inactivation of the Na+ voltage-gated ion channels
55
Absolute refractory period
while inactivation gate of Na+ is closed, cell is unresponsive to another stimulus. Immediately following the firing of a nerve fiber, it cannot be stimulated.
56
What is the function o the Absolute refractory period?
limits the frequency of action potentials and ensures action potential does not move backward toward cell body.
57
What prevents an action potential from "moving backward" to the cell body?
absolute refractory period
58
When are the Voltage-gated K+ channels opened ?
opened by threshold, but 1 msec later than Na+ channels
59
When many K+ leave the membrane, the membrane potential...
hyperpolarizes
60
What type of ions are actively transported out of the plasma membrane?
Na+
61
Relative Refractory Period
many K+ leave cell and membrane becomes negative again. the period shortly after the firing of a nerve fiber when partial repolarization has occurred and a greater than normal stimulus can stimulate a second response.
62
When resting membrane potential is restored the voltage-gated ion channels are open or closed?
closed
63
What as the key event that led to the formation of the nervous system?
evolution of K+ channels with a slightly slower opening time than Na+ channels
64
what would happen if K+ and Na+ channels opened at the same time?
they would negate eachother's effects
65
Speed of Signal Transmission varies based upon?
Axon diameter | Myelination
66
a broad axon provides ______ resistance
less
67
a broad axon provides ______ moving action potentials
faster
68
Myelinated neurons transmit signals ______ than unmyelinated
faster
69
Saltatory conduction
action potential seems to "jump" from node to node (occurs in Nodes of Ranvier)
70
What are the only areas of the axon that have enough Na+ channels to elicit an action potential?
Nodes of Ranvier
71
Synapses
junction where nerve terminal meets a neuron, muscle cell, or gland.
72
Presynaptic cells
send a signal into a synaptic cleft
73
Postsynaptic cell
receives the signal
74
Two different types of synapses:
Electrical synapses | Chemical synapses
75
Chemical synapse
the presynaptic neuron releases a neurotransmitter that binds to a receptor located in the postsynaptic cell.
76
Electrical synapse
the presynaptic and post synaptic cell membranes are connected by channels that are capable f passing electrical current, causing voltage changes in the presynaptic cell to induce voltage changes in the post synaptic cell. Gap Junctions**
77
Which type of synapses uses gap junctions?
electrical synapse
78
In chemical synapsis, which type of synaptic nerve (PRE/POST) contains vesicles of neurotransmitters?
Presynaptic
79
What process, in the presynapitic nerve cell, releases neurotransmitters into the synaptic cleft?
exocytosis
80
In chemical synapsis, binding a neurotransmitter in the synaptic cleft changes what?
the membrane potential of the postsynaptic cell.
81
EPSP - excitatory postsynaptic potential
bring membrane closer to threshold potential.
82
IPSP - inhibitory postsynaptic potential
takes membrane father from threshold potential (usually hyper-polarizes)
83
When does a chemical synaptic signal end?
when neurotransmitter is broken down by enzymes or aken back into presynaptic cell for reuse.
84
3 types of Neuron response in Chemical synapses?
Synaptic integration spatial summation temporal summation
85
synaptic integration
integrates multiple inputs to single neuron
86
spatial summation
when two or more EPSPs or IPSPs are generated at one time along different regions of the dendrites and cell body, their effect SUM each other.
87
Temporal Summation
Two or more EPSPs arrive at same location in quick succession.
88
Equilibrium potential
opposing forces of chemical and electrical gradients where there is no net movement of ions.

Biology 224 (9 decks)

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