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ANP1106 > Lecture 1: Nerve Impulses and Synaptic Tranmission > Flashcards

Lecture 1: Nerve Impulses and Synaptic Tranmission Flashcards

1
Q

Somatic Motor Neve Fibres bring impulses from ___ to _____

A

From the CNS to Skeletal Muscles

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2
Q

What Nervous system is Voluntary?

A

The Somatic Nervous System

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3
Q

Visceral Motor Nerves control

A

smooth muscle
cardiac muscle
glands

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4
Q

What Nervous System is involuntary

A

The Autonomic Nervous System

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5
Q

What are the two types of cells in the Nervous System

A
  1. Neurons
  2. Neuroglial Cells
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6
Q

Neurons are excitable Cells
True or False

A

True

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7
Q

Explain the phrase “ Neurons are excitable cells”

A

They respond to stimuli by changing membrane potential and transmit electrical signals

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8
Q

What doe Resting Membrane Mean

A

The electrical charge of a neuron when it is not active
-70mV

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9
Q

What are 2 things that can produce a change in membrane potential?

A
  1. alteration in ion concentrations on both sides of the membrane
  2. Changes in permeability to any ion
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10
Q

What change in the membrane potential is important for information transferring?

A

Changes in permeability - the number of open channels

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11
Q

What is a Graded Potential?

A

A membrane potential that varies in magnitude in proportion to the intensity of the stimuli

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12
Q

Graded Potentials carry signals over long distances.
Tue or False

A

False: incoming signals operate over short distances and have variable strengths

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13
Q

Action Potentials send signals over long distances.
True or False

A

True: Action potentals send signals over long distances and never lose their strength.

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14
Q

The messeges sent by action pontials will lose stregth by the time they arrive to the CNS
True or False

A

False: Action Potentials do not decay over distance traveled

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15
Q

What is Depolarization

A

A decrease in the resting membrane potential where the inside of the membrane becomes less negative and moves closer to 0

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16
Q

What is Hyperpolarization?

A

When the cell becomes more negative

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17
Q

During resting membrane potential the gated Na+ and K+ channels are open or closed?

A

closed

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18
Q

What 3 events occur during an action potential?

A
  1. depolarization
  2. Repolarization
  3. Hyperpolarization
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19
Q

In order for an action potential to start what must happen first?

A

a stimulus (trigger) has to depolarize the cell body, causing positive ions to flow into the cell body. The positive ions pass through channels that open when a neurotransmitter binds to the channel and tell it to open

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20
Q

What causes an Action Potential to be sent?

A

The cell body becomes positive enough to trigger the voltahe gated Na+ channel found in the axon.

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21
Q

What is repolarization?

A

When the cell is brought back to resting potential

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22
Q

What are the steps of depolarization

A

voltage-gated Na+ channels open
Na+ ions flow into the axon depolarizing it
the neuron goes past equilibrium and becomes positively charged as the Action potential passes through

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23
Q

In Depolarizations the Na+ channels are open or closed?

A

Open

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24
Q

Describe steps of depolarization

A

the cell is brought back to resting membrane potential by Na+ channels closing, which stops the influx of positive ions
The K+ channels open and more K+ leaves the cell than comes back into it which causes the cell to lose positive ions and returns to the resting membrane potential

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25
In repolarization the Na Channels are ___ and the K channels are_____
Na+ channels are closed K+ channels are open
26
Describe Hyperpolarization
The cell is made more negative as the action potential passes through. The K+ channels stay open and continue to let positive ions exit the neuron. As the K+ channels close the Sodium-Potassium pump works to reestablish the resting membrane potential
27
During hyperpolarization the cell becomes more negative True or False
True
28
What is the synaptic Tranmission
When the action potential is converted into a chemical signal and is released into the synapse at the synaptic cleft of the neuron
29
The Chemical Synapse is more common then an electrical synapse. True or False
True
30
Electrical impulses are rare and occur quickly True or False
True
31
Which synapse can be both undirectional and bidirectional and synchronize the activity of all interconnected neurons?
Electrical
32
What synapses are responsible for jerking eyes
Electrical
33
What kind of synapses are specialized for the release and reception of neurotransmitters?
Chemical
34
The presynaptic and Postsynaptic membrane are separated by?
Synaptic cleft
35
What is the first step of neuromuscular junction?
An action potential arrives at the presynaptic axon terminal
36
Describe the Neuromuscular Junction
AP arrives voltage-gated Ca+ channels open and Ca+ enters the axon terminal this causes synaptic vesicles to release neurotransmitters by exocytosis. The neurotransmitter diffuses across the synaptic cleft and binds to specific receptors on the post synaptic membrane Binding the neurotransmitter opens the ion channel, which greats graded potential and the neurotranmitter effects are terminated
37
What causes the postsynaptic neuron to be either excited or inhibited?
the receptor protein and neurotransmitter it binds to and the type of channel it controls
37
What is an ionotropic Receptor
a receptor protein that includes an ion channel that is opened when the receptor is bound by an agonist
38
What is a metabotropic receptor
G protein-coupled receptor and effector in 3 steps 1. binding of neurotransmitter to the receptor protein 2. activation of G-proteins 3. Activation of effector system
39
Describe Reuptake
When the neurotransmitter is reabsorpbed by the sending neuron. usually through astrocytes or the synaptic terminal
40
Describe Degrdation
When neurotransmitter is degraded by enzymes from the postsynaptic membrane or synaptic cleft
41
Explain Diffusion
The neurotransmitter diffuses away from the synapse
42
What is the name of the neurotransmitter found at the neuromuscular junction and in the CNS
ACh
43
What are the two most common mamino acids in the CNS
GABA and Glutamate
44
What is the function of GABA
It is an inhibitory neurotransmitter that causes hyperpolarization
45
What is the function of Glutamate?
An excitatory neurotransmitter that causes depolarization
46
If a neurotranmitter is direct how does it act?
It will bind and open ion channels
47
If a neurotransmitter is Indirect how does it act?
The neurotransmitter will act through intracellular second-messenger molecules
48
Neurotrasmitter will act direct to cause rapid response in postsynaptic cells by altering membrane potential True or False
True
49
A neurtranmitter will act with indirect actions to produce broader, long last effect, acting through intracellular second messenger molecules True or False
True
50
Direct Neurotransmitters behave similar to that of hormones. True or False
False Direct neurotranmitters act similar to hormones.
51
What is a Neuromodulator?
A chemical messenger release by a neuron that does not cause excitatiry behaviour or inhibitory behaviour
52
How does a neuromodulator work presynaptically and give an example
affects the strength of synaptic transmission by influencing the synthesis, release, degradation and reuptake of neurotransmitters Adenosine and nitric oxide
53
How does a modulator work postsynaptically
It alters the sensitivity of the postsynaptic membrane to neurotransmitters
54
A neuromodulator acting presynaptically works by changing the sensitvity of the postsynaptic membrane True or False
False It works presynaptically by influencing synthesis, release, degradation, reuptake
55
Chemical channels are relatively insensitive to changes in membrane potential. True or False
True
56
Where do Graded Potentials Occur
Cell Body and Dendrites
57
Where do Action Potentials Occur?
in the axon
58
Graded potentials travel ____ distance while Actions Potentials travel____ distance
Graded potentials travel short distances while actions potentials travel long distances
59
Which potentials vary in size and decay with distance traveled
Graded
60
Which potentials are always the same size and do not decay with distance
Action Potentials
60
What type of stimulus is necessary for Gated potential
Chemical stimulus or sensory stimulus (light, touch, pressure)
61
What type of stimulus is necessary for action potential
Voltage stimulus - depoloarization triggered by gated potential reaching threshold
62
Summation occurs in both graded and action potentials. True or False
False - Summation only occurs in graded potentials
63
What happens in summation?
The stimulus is added together to increase the amplitude of the graded potential (build upon each other)
64
What is temporal summation?
Summation in the postsynaptic cell of input over time - occurs over time
65
What is Spatial Summation
Intergration by a postsynaptic neuron of inputs from multiple sources - Comes from different sources
66
What Is EPSP and IPSP and what kind of potential are they?
Excitatory Postsynaptic Potential Inhibitory Post Synaptic Potential Both are graded potentials
67
EPSP cause depolarization and IPSP causes Hyperpolarization. True or False
True
68
EPSP open chemically gated ion channels that allow ___ and ___ fluxes to occur simulatneously.
Na+ and K+
69
IPSP opens what kind of channels? (2)
K+ and Cl-
70
The first gate opened by voltage-gated channels is ____ followed by ____
First is Na+ channels followed by K+ channels
71
Explain peak membrane potential of EPSP
depolarization that moves the membrane potential 0mV
72
Explain the peak membrane potential of IPSP
hyperpolarization that moved the membrane toward -90mV
73
A single EPSP cannot induce an action potential. True or False
True
74
When threshold is reached by the gated potential what happens
an action potential fires
75
An action potential will occur if the membrane potential crosses its threshold. However, if it does not reach its threshold what will happen?
The leakage channels will retore the membrane potential to -70mV
76
Describe a Diverging Circuit
One input with many outputs a single neuron in the brain can activate 100 or more neurons in the spinal cord and thousands of skeletal muscle fibers
77
Describe a Converging Circuit
when different stimuli can all elicit the same memory
78
Describe reverberating Circuit
circuit that has signals travelling through a chain of neurons, with each feeding back to the previous neuron. Hold memory information

ANP1106 (10 decks)

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