Foundations of neuroscience week 6 Flashcards
(133 cards)
1
Q
Neurons have several maim parts common to all human cells
A
Soma
Nucleus
Membrane
2
Q
Dendritic are covered in
A
Dendritic spines
3
Q
Dendritic spines
A
Small protruding structures found on thr surface of dendritic in neurons
4
Q
Acts
A
Acts as a receiving point for chemical release by other neurons
5
Q
Neuronal azons are coated in
A
Myelin
6
Q
Myelin sheath
A
Is a insulting material derived fringe specialized giap cells
7
Q
Acts
A
To speed up action potentials (the electrical signals of neurons)
8
Q
There are some (fewer) __ in the brain
A
Unmyelinated neurons
9
Q
Schwann cells
A
Are glial cells that produce myelin but can only myelinate a single axon; they are located in the peripheral nervous system
10
Q
Oligodendrocytes
A
Are glial cells that produce mylin, and can myelintlate mutiple; they are located in the central nervous system
11
Q
Myelin is produced by
A
Glial cells
12
Q
In the vrain myelin is produced by
A
Oligodendrocytes
13
Q
Nodes of ranvier
A
Gaps in myelin
14
Q
what happens when myelin is damaged
A
neuron signaling slows down
15
Q
this is the cause of
A
multiple sclerosis
16
Q
multipe sclerosis
A
a chronic disease of the central nervous system (thought to be an autoimmune disease) caused by the loss of myelin around neuronal axons
17
Q
membrane
A
a lipid bilayer surrounding neurons, controlling ion flow, signal reception and cell communication for neuron function
18
Q
in neurons the membrane plays a crucial role in
A
regulating electrical activity of the cell
19
Q
embedded in the membrane are
A
proteins
20
Q
such as
A
ion channels
21
Q
resting potential
A
is the baseline electrical charge across a neurons membrane when at rest
22
Q
the extracellular fluid
A
the difference in charge between inside the cell and outside the cell
23
Q
this electrical charge is about
A
-70 millivolts
24
Q
this charge is maintained by two key features
A
ion channels
sodium potassium pump
25
ion channels
specialized proteins in the cell membrane that selectively allow specific ions like sodium, potassium, calcium and chloride to pass through
26
sodium potassium pump
a cellular protein that actively transports sodium ions out of cells and potassium ions into cells, maintaining ion balance essential for cell function
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these two mechanisms maintain the __ negative charge inside of the neuron
-70m charge
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this charge is relative to the
extracellular fluid (cytoplasm)
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The resting potential is required for
action potentials to occur
30
what is required for action potentials to occur
the resting potential
31
action potential
is a very brief shift in a neurons electrical charge that travels along an axon
32
during an action potential there is
there is a sudden reversal in the electrical charge of the cell
33
__ from the extracellular fluid rush into the cell
Ions
34
the electrical charge from inside the neuron rapidly, reverses from about
-70mv to about +30mv
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this reversal is called
depolarization
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action potential typically beginds near
the soma of the neuron
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it then
propagates down the length of the axon rapidly
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this is aided by
myelin
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it increases the speed so
this charge can propagate down the length of the axon
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this allows
individual neurons to send information over quite long distances ( the length of their axon
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when an action potential begins __ executed
full executed
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what happens when simulation of a neuron reaches a certain threshold
it triggers a full- strength action potential while sub-threshold stimuli do not produce any response
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what is the all-or-none law
neurons either fire an action potential or they don't
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since action neurons only have on and off states intensity of stimuli
must be codded
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action potentials can occur at very
high rates
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some neurons can fire action potentials
tens or hundreds of times per second
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faster firing =
more intense
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after the reversal of the neurons charge there is
a brief period before it can reset back to normal resting potential
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during this period its is not possible for
the neurons to fire again
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absolute refractory period
the minimum length of time after an action potential during which another action potential cannot begin
51
neuronal axons out to __ with other neurons
communicate
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those axons often reach the __
dendrites of another neuron
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we call the first neuron
pre-synaptic
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we call the second neuron post-synaptic
the neuron receiving a signal
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pre-synaptic
the neuron sending a signal
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post-synaptic
the neuron receiving a signal
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when neurons form a connection with other neurons
synapse
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synapse
is a specialized junction or connection between two neurons that allows for the tranelectrochemical signals
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it is where __ and __ occur in the nervous system
communication and signal transmission
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it enables
neurons to transmit information to other cells
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most neurons dont __ each other
touch
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synaptic gap
the small space between the axon terminal of a pre-synaptic neuron and post-synaptic neuron
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what happens here
chemicals are released form the pre-synaptic neuron onto the post-synaptic heron
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allows for
neurons to communicate chemically
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the primary mechanism by which neurons communicate is
through chemical transmission
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neurons send __ across the synaptic gap
molecules
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neurotransmitters
chemical messengers that facilitate communication between neurons
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there are 8 key stages in neurotransmission
1) synthesis
2) transportation and storage
3) release
4) binding
5) deactivation
6) autoreceptor activation
7) reuptake
8) degradation
69
in order for neurotransmitters to be released, they
they must first be produced
70
neurotransmitters are produced within
neurons from precursor molecules
71
synthesis
the process by which the body produces neurotransmiters which are essential for nerve cell communication
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where are neurotransmitters stored
stored in containers called vesicles
73
synaptic vesicle
a small structure within a neuron that stores neurotransmitters, releasing them into the synaptic cleft to facilitate communication with other neurons
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neurotransmitters produced in the cell body of a neuron must then be
transported to the axon where they will be released
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the release of neurotransmitters is triggered by action
action potentials
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action potentials travel
down the axons length
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when they reach the end there are
axon terminals
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when the action potential reaches an axon terminal it causes
neurotransmitters to be release into the synaptic gap
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exocytosis
the process of moving molecules form within a cell to the exterior of the cell
80
neurotransmitters travel across the synapse and bind to the post-synaptic cell causing
some biological change/activity in the post-synaptic cell
81
receptors
proteins on the surface of neurons that neurotransmitters bind to, allowing for the transmisson of signals between the nerve cells
82
what happens when a reurotransmitter reaches a post- synaptic neuron
neurotransmitters bind to a receptor which can excite or inhibit the neuron that they bound to
83
this makes it
either more or less likely to fire an action potential
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excitation
occurs when neurotransmitters increase a neurons potential for firing an action potential
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inhibitition
happens when neurotransmitters decrease a neurons potential for firing an action potential
86
after binding the effects of neurotransmitters must be
neutralized
87
this occurs when
the neurotransmiteer unbinds from these receptors
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prevents
neurotransmiters from having neveer0-ending effects in the synapse
89
deactivation
the process of terminating or reducing the effect of a neurotransmitter in the synaptic cleft to ensure controlled neural signaling
90
what happens to neurotransmitters left unbound in the synaptic gap
91
there are three main prcoesses by whihc neurotransmitters are elmintaed form the synapse
1) diffusion
2) reuptake
3) degradation
92
diffusion
neurotransmitters simply drift out of the synaptic cleft where they are absorbed by glial cells
93
some neurotransmitters also bind to the neuron that
released them
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autoreceptors
receptors on the releasing (pre-synaptic) neuron
95
reuptake
the reabsorption of a neurotransmitter by the presynaptic neuron after it has been released into the synaptic cleft
96
some neurotransmitters may also be removed form the synaptic gap by
being reabsorbed by the pre-synaptic neuron
97
enzymes can facilitate deactivation by
breaking apart neurotransmitter molecules
98
enzymatic degradation
when enzymes in the synaptic cleft break down neurotransmitter molecules into inactive byproducts terminating their signaling effect
99
neurons produces many
different types of neurotransmitters
100
some neurotrasnmitters are only produced by
specific small groups or neuorns in the brain
101
neurotransmitters share four common properties
1) they are synthesized in the neuron
2) they are stored in the synaptic terminals
3) they are released when a neuron has an action potential
4) they are deactivated/removed form the synapse after neurotransmisson
102
the primary inhibitory neurotransmitter in the brain
GABA
103
when it binds to GABA receptors it
neuronal excitation when it binds to GABA receptors
104
the primary excitatory neurotransmitter in the brain
glutamate
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when it binds to glutamate receptors it
increases neuronal excitation when it binds to glutamate receptors
106
serve as the
the most abundant-common neurotransmitter in the brain that serve these two functions
107
both are narrowly or widely distributed throughout the brain
widely
108
many anti-anxiety drugs work by
targeting GABA
109
two examples
Benzodiazepines valium/diazepam
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works by
suppressing CNS activity
111
this is because
GABA is a primarily inhibitory neurotransmitter ( reduces GABA is a primarily inhibitory neurotransmisson/arousal)
112
monoamines
are a group of GABA is a primarily inhibitory neurotransmitter
113
say 3 examples
dopamine, noradrenaline (norepinephrine) and serotonin
114
dopamine is involved in
moment and reward (pleasure)
115
give two examples when its released
eating, sex, etc.
116
noradrenaline
mobilize the brain and body for action, increases attention and vigilance; released during stress/fear (fight-or flight response)
117
serotionin
involved in many complex behaviours/cognitions
118
gives three examples of cognitions its involved in
sleep, mood, memory
119
dopamine is secreted
small group of neurons in the brains
120
when these become damages it leads to
parkison's disease
121
parkinsons disease
a progressive neurological disorder characterized by symptoms like tremors, slowness of movement, muscle stiffness and balance problems
122
many antidepressant drugs target
serotonin
123
give an example
Selective serotonin reuptake inhibitors
124
SSIs function by
blocking serotonin reuptake which leaves more serotonin in the synaptic gap
125
Norepineprhine is synthesized form
dopamine
126
acts as
a neurotransmitter and as a hormone
127
Drigs fro attention deficit disroders typically traget
NE
128
Give an example
Amphetamines
129
Amphetamines ___ Ne levels in the ___
increase brain
130
Acetylcholine is the only
transmitter between motor neurons and voluntary muscles
131
required for
all movement
132
primary neurotransmitter of the
parasympathetic nervous system
133
some posions block acetylcholine give two examples
atropa belladonna (deadly nightshade)
