Chapter 2; Neurobiology Flashcards
(299 cards)
1
Q
How many neurons in the human brain?
A
85-100 billion
2
Q
Neurobiology is the study of the ____ ____ and how the ____ works. Basic operating principals of the ____ ____, right down to ____ and ____ properties.
A
nervous system
brain
nervous system
electrical, chemical
3
Q
The vertebrae neuron is ____ and measures approximately ____ ( _ x _ ^_ m) in diameter and up to more than a ____ in length.
A
microscopic
10 to 20 microns
1 x 10^-6, meter
4
Q
Neurons are ____ packed.
A
densely
5
Q
Glia: equal ____ to the neuron, and non-____ ____ cells.
A
volume
non-neuronal supporting
6
Q
What is evolutionarily conserved in regard to the neuron?
A
unchanged; the neuron is basically the same across all vertebrate animals
7
Q
Neurons are the ____ and ____ units of the nervous system.
A
structural
functional
8
Q
A nerve is ____ and consists of a bundle of dozens to hundreds of ____ packed together in a ____ ____ ____.
A
macroscopic
neurons
connective tissue sheath
9
Q
The neuron is a ____ cell used for ____ information between the ____ and your ____ from one region to another.
A
specialized
transmitting
brain
body
10
Q
How is the neuron information transmitted (what form)?
A
electrochemical signals
11
Q
Neuron sends information in what 2 ways?
A
Conduction of electrical impulses
Release of chemicals
12
Q
What is the conduction of electrical impulses?
A
Action Potential
13
Q
What is the release of chemicals?
A
Neurotransmitters
14
Q
What are recognized and received by another neuron?
A
Neurotransmitters
15
Q
How does the typical neuron send neurotransmitters? And what is it?
A
Across the synapse
Microscopic gap between cells
16
Q
What does the postsynaptic neuron do with the chemical signal (neurotransmitter)? What does this trigger? And that activates a release of what?
A
Converts to an electric signal
An action potential
It’s own neurotransmitters
17
Q
What are the 4 main components of a neuron?
A
Dendrites
Soma
Axon
Terminal Buttons
18
Q
The dendrites receive and recognize ____ released from other cells and ____ the ____ signal into an ____ ____ signal.
A
neurotransmitters
convert
chemical
intracellular electrical
19
Q
What signal travels down the dendrites? To what?
A
Electrical
Soma
20
Q
What contains all of the machinery for manufacturing neurotransmitters?
A
Soma
21
Q
What transmits the electrical signal from the dendrites?
A
Soma
22
Q
What are the two main functions of an axon?
A
Transport neurotransmitters from soma to terminal boutons
Generate and conduct action potential down to the terminal buttons
23
Q
Terminal buttons are responsible for ____ ____ for eventual release in response to arrival of an ____ ____ .
A
storing neurotransmitters
action potential
24
Q
3 ways neurons are classified
A
shape
function
location
25
____ neurons compromise majority of nervous system.
multipolar
26
____ neurons have ____ processes which functions with a ____ end and a ____ end. Where are these found?
```
Bipolar
Two
Sending
Receiving
The retina of the eye
```
27
What process is the sending end called?
axonal process
28
What process is the receiving end called?
dendritic process
29
____ have a ____ process attached to the soma. Where is this found?
Unipolar
Single
Sensory System
30
What are the four components of neuron covered in?
Cell membrane
31
The cell membrane is a ____-____ membrane that ____ the entire ____.
double-layered
envelops
neuron
32
What is the cell membrane composed of?
Phospholipid Bilayer
33
The phospholipid bilayer consists of ____ phosphate molecules ("head") sandwiching ____ fatty acids (____) in between ("____").
polar
non-polar
lipid
tail
34
Phosphate heads are ____ or attracted to ____ which is also polar.
hydrophilic
Attracted to water
Polar
35
Describe phosphate head and tails in relation to water?
Head interacts with water in extracellular space in cytoplasm of cell.
Tail avoids water and is protected by phosphate head.
36
The ____ ____ is a specialized ____ (small "organ" of the cell) that regulates movement of ____ in and out of the ____ which allows ____ between the ____ space of a cell's ____ and controlling the ____ changes of the neuron.
```
cell membrane
organelle
molecules
neuron
communication
extracellular
interior
electrical
```
37
____ permeability:
| ____ , ____ , and/or ____ molecules do not go through the ____ by ____ (or ____ ).
```
semi
large
polar
charged
membrane
diffusion
osmosis
```
38
What is a lipid?
fatty acids and insoluble in water
39
Difference between polar and nonpolar?
Polar: electrons unequally shared by two atoms
| Non-polar: electrons equally shared by two atoms
40
What kind of molecules readily diffuse through the membrane?
Small or lipid-derived molecules
41
What gives the cell membrane the ability to regulate cellular communication?
Membrane-Embedded Protein (MEP)
42
What three ways do the cell get the molecules through the membrane?
Transporter, Channel, and Receptors
43
How does the Transporter work (MEP)?
It functions like a pump. It spans the thickness of the membrane and uses energy (ATP) to actively transport nondiffusible molecules into and out of the cell.
44
What is ATP and what is it the source of?
Adenosine triphosphate; the cell's source of energy
45
How does a Channel work (MEP)?
They are specific for particular ions and can be opened and closed depending on conditions. This is selective permeability.
46
Which MEP does not transmit molecules across the membrane?
Receptors
47
How does a Receptor work (MEP)?
Like a lock on a door. A molecule, like a neurotransmitter, connects or binds to a receptor that is specific for that molecule.
48
With a Receptor (MEP), after the molecule is binded, what happens?
The receptor changes, sends a piece of that information into the cell, letting the cell know the message from the extracellular space has been "received."
49
What are amino acids?
Building blocks of proteins
50
What are most neurotransmitters derived from?
amino acids
51
Where are neurotransmitters made?
In the vicinity of the nucleus of the cell
52
Where is the nucleus of the cell?
Found in the soma
53
What structure of the cell contains chromosomes?
The nucleus
54
What are chromosomes?
Densely packed strands of DNA
55
Many neurotransmitters consist of a single ____ ____ that has been modified slightly.
amino acid
56
Neurotransmitter serotonin is just a modification of the dietary amino acid ____
tryptophan
57
In making of a neurotransmitter, what is split apart and what is it transcribed into?
the double helix of the DNA
| mRNA (messenger ribonucleic acid)
58
mRNA is a ____ ____ of ____ with ____ pairs that correspond to the ____ ____ molecule.
single strand
nucleotides
base
parent DNA
59
In making of the neurotransmitter, after the DNA is transcribed into mRNA, what is translated to assemble chains of what?
The mRNA is translated to assemble changes of amino acids
60
What determines which amino acids are to be taken from the cytoplasm and assembled into proteins?
The unique sequence of nucleotides
61
The ____ is another intracellular ____ that runs down the ____ reading three ____ sequences at a time that correspond to a specific ____ acid.
```
Ribosome
organelle
mRNA
nucleotide
amino
```
62
A ____ is a particular sequence of ____ that codes for the production of a specific ____ or ____ .
gene
nucleotides
protein
trait
63
Proteins are ____, like muscle or keratin, or ____, like enzymes.
Structural
| Regulatory
64
____ proteins regulate ____ reactions, controlling a wide variety of processes such as ____ synthesis, ____ (ie. breakdown), and thousands of other ____ functions.
```
Regulatory
chemical
neurotransmitter
degradation
metabolic
```
65
Starting with the soma, walk me through the steps to a neurotransmitter?
```
Soma to
cell body to
nucleus
To chromosomes (densely packed DNA) and
DNA splits and transcribed to
mRNA that is translated into
Amino Acids
```
66
Where are the newly synthesized neurotransmitters processed?
The Golgi Apparatus
67
What is the Golgi Apparatus?
Encloses the neurotransmitters inside a synaptic vesicle
68
What is a synaptic vesicle?
A bag of membranes that contains the neurotransmitters
69
Neurotransmitters have to be ____ (ie. stored and protected) inside of ____ in order to protect them from ____ ____.
sequestered
vesicles
degradative enzymes
70
What are degradative enzymes, and what can this lead to?
break down and permanently alter chemical structure, which can lead them to be inoperative
71
Where are the neurotransmitters sent to after being stored into the vesicles?
They are sent to the terminal buttons.
72
Where are neurotransmitters stored?
Terminal buttons
73
When the Golgi is complete, organelles known as ____ function as a conveyer belt for ____ vesicles down the length of the ____ through a process called ____ ____ .
microtubules
transporting
axon
axoplasmic transport
74
The vesicles that store the ____ keep them stored until they release the ____ into the ____ .
neurotransmitters
neurotransmitters
synapse
75
The arrival of what causes the release of a packet of neurotransmitters?
Action potential
76
What two things travel down the axon towards the terminal? Which is faster?
```
Synaptic vesicles
Action Potentials (faster)
```
77
Action Potentials represent movement of ____ charge and travel down the ____ in time measured in ____ .
electrical
axon
milliseconds
78
Axoplasmic transport takes ____ to ____ to occur and involves ____ movement of ____ .
hours
days
physical
molecules
79
Half of the volume of the brain consists of ____ - ____ cells known as ____ which are also known as ____ cells.
non-neuronal
glia
supporting
80
What are the four kinds of Glial Cells?
astrocytes (star-cell)
Microglia
Eligodendrocytes
Schwann
81
Which type of glial cells provides nutritional and physical support for neurons?
Astrocytes
82
Which type of glial cell are small, branches cells that wrap their tentacles around capillaries?
Astrocytes
83
When a neuron dies, which glial cell secretes extracellular material that replaces the lost neuron with scar tissue (sclerosis)?
Astrocytes
84
What glial cell helps the immune system rid the brain of foreign material and cellular debris by holding on to and presenting these substances to the macrophages of the immune system that engulf (phagocytose) the material in order to remove it?
Microglia
85
What glial cell has processes that wrap around axons and create the myelin sheath?
Oligodendrocytes
86
What is an insulative covering?
The myelin Sheath
87
Myelin is a ____ substance that insulates ____.
fatty
| axons
88
What is the CNS?
Central nervous system
89
What is the PNS?
Peripheral nervous system
90
The PNS contains only ____ cells (a glial cell) which are the analogs of the CNS's ____ .
Oligodendrocytes
91
What enables action potentials to be conducted down the axon very efficiently and rapidly?
The myelin sheath
92
Which type of vertebrate completely lacks myelin?
Invertebrates
93
What is a physical parameter that "resists" the flow of electrical signals?
Resistance
94
Resistance can ____ down signals and make them ____ across distance.
slow
| dissipate
95
Vertebrates have ____ resistance? (low/high)
high
96
Do vertebrate neurons conduct action potentials at a faster rate compared with invertebrates or slower? Why?
Higher
| Special properties of the myelin sheath
97
Technical term for cutting axons is what?
Denervation
98
In CNS, do denervated axons attach to their target?
No, they do not reattach.
99
The spinal cord and brain consist of a very ____ and complex array of ____ .
dense
| neurons
100
Differences in post-denervation recovery are conferred by major differences in the ____ in CNS vs PNS
glia
101
What is the fundamental different between the two myelin sheath-prodcuing cells? Examples of oligodendrocyte and Schwann
how they wrap around the axon.
Oligoendrocyte has several branches that warps around handful of axons so when the neuron is denervated, the branches wither back and if there is an attempt to grow back there is no guide.
Schwann wraps its whole body around a single axon and remains in place after denervation, when it grows back there is a path of tunnels still in tack.
102
Which has better neuronal recovery: CNS or PNS?
PNS
103
What triggers a neurotransmitter's release from the synaptic vesicles waiting in the terminal boutons?
An action potential
104
Neurons are ____ batteries (in contrast to nerves that are ____ )
microscopic
| macroscopic
105
The neuron stores ____ energy
potential
106
What is potential energy?
Energy that is stored-up, to allow for its later release
107
Potential energy in a neuron comes in the form of what?
membrane potential
108
Membrane Potential is defined as a difference in ____ on the ____ ( ____ ) of a cell vs. the ____ of the cell ( ____ ____).
```
voltage
inside
cytoplasm
outside
extracellular fluid
```
109
What is it called when the membrane potential is at rest or not doing anything in particular, not firing an action potential?
Quiescent
110
The membrane potential registers at ____ ____ (mV0.
-70 millivolts
111
The reading of -70mV represents the ____ ____ .
Resting potential
112
The membrane potential is the difference in ____ whereas the resting potential represents the ____ .
voltage
| -70mV
113
What is the goal between the soma to the terminal?
To fire an action potential
114
It is the deviation from 0mV that represents and gives rise to the potential ____ .
energy
115
The action potential comes in the form of a release of the stored ____ ____ or a resting cell and a tremendous positive deviation in ____ ____ away from the negative ____ ____ .
potential energy
membrane potential
resting potential
116
The action potential will represent a swing from ____ mV all the way up to about ____ mV.
-70
| +40
117
Every living cell contains ____ and is bathed in ____ fluid.
cytoplasm
| extracellular fluid
118
Cytoplasm and extracellular fluid contain a large number of ____ .
molecules
119
Particular important to membrane potential are the charged elemental particles knows as ____ .
ions
120
Positively charged ions are ____ and negatively charged ions are ____ .
cations
| anions
121
Extracellular fluid is basically saline as it compromised of ____ ( ____+)( ____(type of ion)), and ____ ( ____ -)( ____ (type of ion)) ions.
sodium Na+ cation
| Chloride cl- anion
122
There are Na+ and Cl- ____ the cell as well as other ions inside and outside of the cell (like ____ ( ____ +)), organic ____ ( ____ and ____ acids), and ____ ( ____ ++).
```
inside
Potassium, K+
anions
proteins and amino acids
Calcium, Ca++
```
123
The differential distribution of specific ions on the ____ and ____ of the neuron will give rise to the ____ ____ , and actual movement of ions through the ____ ____ will generate the ____ ____ .
```
inside
outside
membrane potential
cell membrane
action potential
```
124
What is the push or pull on ions that compels them to move in a direction into or out of a cell?
Force
125
What is the actual movement of ions during an action potential?
Flux
126
What is the difference between force and flux of ions?
Force is the compelling push or pull whereas the flux is the actual movement during action potential
127
Extracellular fluid (saline) means that what will be found outside of cells due to that higher concentration (measured in ____ )?
Na+ and Cl-
128
Na+ and Cl- ____ in a solution.
dissociate
129
____ + operates in nearly every way opposite of Na+
K
130
If Na+ is found in a higher concentration outside the cell, what is found in higher concentration inside the cell?
K+
131
What are the two forces that act on ions?
Concentration gradient (CG) and electrostatic pressure (EP)
132
In a concentration gradient, the ions will want to move from areas of a ____ concentration to a ____ concentration.
higher
| lower
133
In a concentration gradient, ions strive towards a ____ state.
balanced
134
Concentration gradient or the ____ of ____ .
force of diffusion
135
The size of the ____ for a given ion can be measured ____
force
| empirically
136
Forces are measured in ____ (in ____ values)
mV
| absolute
137
CG Na = ____ mV
50 in
138
CG Cl = ____ mV
70 in
139
CG K = ____ mV
90 out
140
The cell membrane is polarized, hyperpolarized(more neagative), or depolarized(more positive)?
Polarized
141
The ____ ____ is determined by the uneven distribution of ____ ( ____ particles) between the inside and outside of the cell, and by the different ____ of the membrane to different types of ____
```
resting membrane
ions
charged
permeability
ions
```
142
Why can't the ions pass directly through the hydrophobic lipid regions of the membrane?
Because they are charged
143
What do charged ions use to get across the membrane?
Specialized channel proteins that are hydrophilic tunnels
144
Some channels known as ____ channels are open in resting neurons. Others are closed in resting neurons and only open in ____ to a signal.
leak
| response
145
The resting ____ ____ depends mainly on movement of ____ + through ____ ____ channels.
membrane potential
k+
potassium leak
146
What are the rules of attraction for ions?
Opposites attract and charges repel
147
Ions get pushed or pulled due to their ____ ____ (or forces due to charge)?
electrostatic pressure
148
What is the resting potential of the neuron?
-70mV
149
What is the mV of the inside of the cell?
-70 mV
150
Is the inside of the cell negative of positive?
negative
151
EP Na = ____ mV
70 in
152
EP Cl = ____ mV
70 out
153
EP K = ____ mV
70 in
154
What does net forces mean?
sum total forces
155
Calculate the net force by ____ the individual net forces per ion, or ____ if the two forces are in the opposite directions.
adding
| subtracting
156
NF Na = ____ mV
120
157
NF Cl = ____ mV
0
158
NF K = ____ mV
20
159
The values and forces can vary across species. The net ____ and relative ____ are consistent across species. The numbers are not a specific representation.
direction
| magnitude
160
Forces determine the actual movement of ions across the cell membrane is known as what?
Ion Flux
161
How does the flux occur?
In the same direction as the force.
162
A property of a membrane is ____ .
permeability
163
What is permeability?
The ease with which ions can pass through the membrane.
164
Charged particles like ions do not readily ____ through ____ ____ .
move
| cell membrane
165
The movement of ions into and out of the cell is completely impeded by the very structure of the ____ ____ .
Lipid bilayer
166
What type of MEP (membrane embedded protein) confers some permeability under certain situations?
Ion Channels
167
Ion channels are ____ molecules that are ____ in and ____ the thickness of the ____ ____ .
protein
embedded
transverse
cell membrane
168
What serves as passageways for ions to travel through the cell membrane allowing for influx and efflux?
Ion Channels
169
What is an influx?
inward flux
170
What is an efflux?
outward flux
171
Are the ion channels simply just tunnels? Why?
No, they have specificity
172
Ion channels allow ____ for only ____ type of ____ .
flux
one
ion
173
The ____ of an ion channel can be modulated up or down by ion channel ____ .
permeability
| gates
174
Channel gates are ____ structures within the channel that can close off a channel or open up to allow passage of ____ depending upon ____ .
protein
ions
conditions
175
What conditions are depending on a channel gate opening or closing?
Membrane voltage or if a neurotransmitter is being received
176
When channel gates are ____ , ____ is high, and ion ____ proceeds.
open
permeability
flux
177
When channel gates are ____ , ____ is low, and ion ____ is impeded or stopped.
closed
permeability
flux
178
Ion channels and gates serve to give the cell ____ ____ .
selective permeability
179
Selective permeability is selectivity for particular ____ under ____ conditions, depending on the status of the ____ .
ions
specific
gates
180
Cl- has a net force of 0 which means there is ____ ____ flux, which means it is in a state of ____
no net
| equilibrium
181
Cl- ions are ____ and ____ at the same rate, which means they are in ____ .
influxing
effluxing
balance
182
At rest, Cl- ____ is high, which means the gates are relatively ____ .
permeability
| open
183
Instead of not moving, Cl- readily moves ____ and ____ of the cell but at ____ rates, hence equilibrium.
in and out
| equivalent
184
Na+ is sitting ____ the cell, with this large inward ____ at rest, you have to have low ____ to thwart Na+ from constantly rushing into the cell.
outside
force
permeability
185
The ____ to Na+ at rest is very ____ and resists the large ____ .
permeability
low
force
186
K+ is trying to ____ the cell with comparatively much less ____ .
escape
| force
187
Having ____ permeability for K+
high.
188
Does Cl- contribute to the resting potential?
Not really.
189
Na+ is attempting to ____ its way into the cell but is resisted by ____ ____ .
push
low
permeability
190
K+; a small outward ____ pushing against low resistance or ____ permeability.
force
| high
191
Small amount of flux is a ____ .
leak
192
At resting potential, Na+ leaks ____ and K+ leaks ____ .
in
| out
193
The unequal distribution of ions would dissipate if the leak was unchecked which result in a drift of -70mV to 0 and the loss of ?
resting potential, losing the potential energy
194
What is the cell's way of compensating for the leakage -what process?
Active Transport.
195
Active transport pumps the leaked ions in the ____ direction of the leak, just enough to compensate for the leakage.
opposite
196
In active transport, a ____ uses ATP to actively ____ molecules into and out of the cell.
transporter
| pump
197
What is the particular transporter called in active transport (compensating for the leaking)?
Na-K transporter
198
The ions are pumped in a ____ ratio, as ____ leaks in slight more than ____ leaks out.
3:2
Na+
K+
199
The Na-K transporter has to continue running to maintain the ____ ____ in an ionic balance called which differs from ____ in that the steady state require the input of ____.
resting potential
steady-state
equilibrium
energy
200
If a cell is deprived of ____ , then not enough ATP (Adenosine triphosphate; the cell's source of energy) can be manufactured to provide ____ for the Na-K transporter.
oxygen
| energy
201
If the Na-K transporter is shut down, the ____ ____ would degrade toward ____ mV, and there would not be enough ____ ____ to fire an ____ ____ and therefore transmit " ____ ". This means, the neuron ____ ____ .
```
resting potential
0
potential energy
action potential
information
shuts down
```
202
It takes a continuous expenditure of ____ to maintain the ____ ____ of the ____ ____ necessary to subsequently do some work (ie. generate an ____ ____ ).
energy
potential energy
resting potential
action potential
203
An ____ ____, once triggered, does not rely upon the input of more energy - it relies completely upon the ____ previously ____ .
action potential
energy
stored
204
In a neuron, it takes work to maintain ____ .
rest
205
The Equilibrium Potential (EqPot) is measured empirically in a laboratory. It is defined as the ____ ____ at which a particular ion reaches its own unique ____. EqPot is when the ____ and ____ for a given ion would be ____ , but in ____ directions.
```
membrane potential
equilibrium
CG
EP
equivalent
opposite
```
206
The EqPot is therefore the ____ ____ at which the ____ ____ equals zero.
membrane potential
| net force
207
EqPot Na+ = ____ mV
55
208
EqPot Cl-= ____ mV
-70
209
EqPot K+= ____ mV
-75
210
What forces change during ion flux and how?
Electrostatic Pressure, in reverse
211
Understanding EqPot. Na+ were to ____ into the cell, then the inside of the cell becomes more ____ creating a diminution of the size of the ____ ____ . At a high enough membrane potential, the EP will ____ and become ____ , eventually becoming equal in size but ____ direction to the concentration gradient. In other words, the membrane potential has to go as high as +55mV in order for Na+ to reach its ____ .
```
influx
positive
electrostatic pressure
reverse
larger
opposite
equilibrium
```
212
____ ____ represents a dramatic increase in ____ that reverses ____ of the cell.
action potential
voltage
polarity
213
The change in the ____ ____ in the ____ direction is called depolarization.
membrane potential
| positive
214
The membrane potential will chance from ____ ,pass ____ ,move into the ____ range, approaching ____ mV, and then return to ____ , all in the matter of less than ____ ms. This burst is known as a ____, the " ____ of ____ " used by the ____ ____ to ____ .
```
rest
zero
positive
+40
rest
3
spike
unit of information
nervous system
communicate
```
215
The sending of the ____ down the axon to the ____ causes ____ to be released.
spike
terminals
neurotransmitters
216
Action Potential consists of simply a ____ of ____ ____ - energy that was previously ____ during ____ ____ (remember the ____ - ____ transporter?).
```
release
potential energy
stored
resting potential
Na-K
```
217
Na+ sits ____ the cell with a large ____ ____ that is kept at bay by ____ permeability.
outside
inward force
low
218
Na+ wants to move into the cell but the gates are mostly ____ at ____ preventing Na+ from getting through the ____ .
closed at rest
| channels
219
Na+ wants to bring the cell to ____ .
EqPot 55mV
220
Na+ represents the ____ ____ that will be released to form the ____ ____ .
potential energy
| action potential
221
What is the region of the cell between the soma and the axon that is really the beginning of the Axon?
Axon Hillock
222
Axon Hillock represents the location on the cell where an ____ ____ is first generated.
Action Potential
223
What is the first region of a cell that has the kinds of channels that allow Na+ to come rushing in the cell to create an Action Potential?
Axon Hillock
224
What is the particular condition that allows the gates that are mostly blocking these channels at rest to suddenly begin to open?
When the membrane potential reaches -60mV
225
When the membrane potential reaches the ____ of - ____ mV, the gates ____ up and allow ____ to influx.
voltage
-60
open
Na+
226
- ____ mV represents a ____ voltage necessary for triggering an ____ ____ . This membrane potential is called the ____ ____ ____ or action potential ____ .
```
60
voltage
action potential
threshold of excitation
threshold
```
227
What decides whether or not to fire an action potential?
The axon hillock
228
What is the decision point of the cell?
The axon Hillock
229
What causes the gates to open?
The voltage
230
When the ____ ____ exceeds the threshold, the ____ structure of the gate ____ changes, causing the Na+ ____ to increase; this allows Na+ to ____ .
```
membrane potential
chemical
proteins
permeability
influx
```
231
What Na+ channels trigger change to their permeability by changes in membrane voltage that bring the membrane potential above the threshold?
Voltage-gated
232
Having a ____ gives the action potential a unique feature.
threshold
233
Action potential is triggered in a " ____ or ____ " manner. There is no turning back.
all or none
234
An action potential comes from the ____ of Na+ via ____ - ____ Na+ channels who gates ____ when the membrane potential reaches the ____ of ____ .
influx
voltage-gated
open
threshold of excitation
235
Where do voltage changes happen before the hillock?
in the soma and dendrites
236
Where does a cell typically receive information from other cells?
The reception of neurotransmitters
237
What is the essence of neuronal communication? To release ____ from its ____ to the next neuron.
neurotransmitters
| terminal
238
In order to trigger an action potential in a post-synaptic neuron, the binding of the neurotransmitter must be ____ into an ____ ____ that gets transmitted to the hillock.
transformed
| electronic signal
239
Neurons transform received ____ information (binding the ____ in dendrites) into ____ information (in the form of ____ ____ in the axon) and then back again to ____ information - in the form of release ____ from the terminal.
```
chemical
neurotransmitters
electrical
action potentials
chemical
neurotransmitters
```
240
What is the type of neurotransmitter that actives cells (ie. leads the receiving cell closer to firing an action potential)?
An excitatory neurotransmitter.
241
Excitation refers to moving the ____ ____ closer to the ____ of ____ and thereby ____ the likelihood of the next neuron firing an ____ ____ .
membrane potential
threshold of excitation
increasing
action potential
242
An excitatory neurotransmitter ____ to a ____ and triggers the ____ to have an effect on ____ + ____ , namely to cause Na+ ____ to ____ up (a small number of them) allowing Na+ to ____ causing a small ____ in the dendrites. That receptor is called ____ (causing a change in ions) which means it is ____ with an ____ channel and thus able to have an effect on the ____ 's gates.
```
binds
receptor
receptor
Na+ channels
gates
open
influx
depolarization
dendrites
ionotropic
coupled
ion
channel
```
243
The resulting depolarization that occurs in the dendrites and soma is called a ____ ____ .
post-synaptic potential (PSP)
244
The post-synaptic potentials are triggered by a ____ binding to an ____ receptor, which, in turn, modifies ____ ____ gates; this configuration is referred to as ____ - ____ .
neurotransmitter
ionotropic
ion channels
ligand-gated
245
A ____ is a generic word for any chemical that binds to a receptor.
ligand
246
If the gates that are opened are ____ channels (allowing ____ to ____ at ____ ____ ) then an ____ ____ ( ____ ) is triggered, meaning that the membrane potential is elevated closer to the ____ of ____ (and therefore more likely to fire an ____ ____ .
```
Na+
Na+
influx
resting potential
excitatory PSP
(EPSP)
threshold of excitation
action potential
```
247
EPSP (excitatory post-synaptic potentials) are subthreshold ____ (individually, they don't typically push the ____ ____ above the - ____ mV threshold).
depolarizations
membrane potential
-60 mV
248
When ____ raise the membrane potential a small deviation and do not exceed the threshold of ____ , the membrane potential returns to ____ as time passes.
depolarizations
excitation
rest
249
The membrane potential exceeds the ____ and triggers and ____ ____ because of the adding of all of the ____ together.
threshold
action potential
EPSP
250
When the ____ is reached at the axon hillock, then an ____ ____ will be triggered.
voltage
| action potential
251
The process of adding EPSPs together is called ____ .
summation
252
EPSPs summate through a combination of ____ ____ (close in time) and ____ ____ (from multiple inputs being received at different parts of the cell).
temporal summation
| spatial summation
253
EPSPs are triggered in the ____ and must travel down them and across the ____ of the ____ . When they travel through the ____ they spread ____ (in all directions) and eventually reaching the ____ .
```
dendrites
cytoplasm
soma
cytoplasm
omnidirectionally
hillock
```
254
As EPSPs spread or ____ across the cell, they lose ____. This ____ is lost due to ____ . With EPSP conduction, resistance of the ____ causes the ____ change of the SPSP to diminish back towards the resting potential. This type of conduction is called ____ ____ , meaning the ____ change ____ over ____ as the EPSP spreads.
```
conduct
energy
energy
resistance
cytoplasm
voltage
decremental conduction
voltage
decreases
distance
```
255
EPSPs are always ____ ; as long as the sum of the EPSPs exceeds the ____ of ____ , then you will get an ____ ____ .
summating
threshold of excitation
action potential
256
EPSPs can consists of ____ of various sizes ( ____ ), which is referred to as a ____ response. What would make a PSP large would be a release of large amounts of ____ onto that cell. A small PSP would mean that small amounts of ____ were released.
```
depolarization
amplitude
graded
neurotransmitters
neurotransmitters
```
257
IPSPs are ____ ____ ____ ____ .
inhibitory post-synaptic potentials
258
IPSPs are triggered by an ____ ____ .
inhibitory neurotransmitter
259
IPSPs work to bring the membrane potential further away from the ____ of ____ (more ____ ) and therefore reduce the cell's changes of firing an ____ ____ .
threshold of excitation
negative
action potential
260
Na+ wants to ____ until 55+ mV.
influx
261
What are anxiolytic?
anxiety-reducing drugs
262
Anxiolytic drugs promote the ____ of ____ and tone down activity in parts of the brain subserving anxiety reactions.
influx
| Cl-
263
The nuerotransmitter ____ ____ ____ ____ ( ____ ) is an ubiquitous (ie. ____ ) neurotransmitter in the brain that regulates overall activity of ____ ____ . ____ accomplishes this by modulating ____ - conductance.
```
gamma amino butyric acid
GABA
brain circuitry
GABA
Cl-
```
264
____ + ____ for IPSPs.
K+ efflux
265
____ + ____ lowers the membrane potential, giving rise to ____ .
K+ efflux
| IPSPs
266
Neurons may receive a mixture of ____ and ____ . When they summate at the hillock, both positive and negative potential changes will get algebraically added and subtracted together. Whatever the ____ ____ happens to add up to at the ____ is the key. it will determine whether or not the ____ - ____ ____ + channels open up and trigger the ____ ____ .
```
EPSPs and IPSPs
membrane potential
hillock
voltage-gated Na+
action potential
```
267
The membrane potential ____ from rest to a very high positive level, and then it dives back down to rest ( ____ ).
depolarizes
| repolarization
268
K+ wants to bring the MP to ____ mV.
-75mV
269
Na+ wants to bring the MP to ____ mV.
55mV
270
Once the threshold is reached, the ____ starts off slowly and then very quickly depolarizes rather dramatically ( ____ ____ ).
depolarization
| exponential acceleration
271
The ____ - ____ ____ + channels begin to open up and allows for some Na+ ____ .
voltage-gated
Na+
influx
272
The Na+ channels ____ open up at the same time as it happens ____ time. Na+ ____ , the membrane potential ____ , causing more ____ to open, leading to more Na+ ____ , and so on.
```
don't
over
influxes
depolarizes
channels
influx
```
273
Slowing down of depolarization is partly because the Na+ ____ are starting to close and therefore slowing down the ____ of Na+. And then the ____ +channel opens and accelerating rapidly which allows for the ____ + ____ .
```
channels
influx
K+
K+
efflux
```
274
The membrane potential dips below the rest is called ____ .
hyperpolarization
275
Action Potentials are generated in the ____ ____ and travel to the ____ to trigger the release of ____ .
axon hillock
terminal
neurotransmitters
276
Starting with the ____ of the Na+ and ____ of K+ at the hillock, an ____ ____ will be released at that place in the cell. To conduct an ____ ____ down the axon, there is going to be a trigger of new ____ ____ sequentially along the length of the axon - not the same ____ ____ . This ____ aspect of it dictates that once it is triggered at the ____ ,it will conduct down the axon and create ____ ____ in the terminal.
```
influx
efflux
action potential
action potential
action potential
action potential
regenerative
hillock
action potentials
```
277
Resting Potential requires the continuous ____ of ____ ( ____ - ____ transporter requires ATP), whereas the action potential requires no additional ____ as it relies upon the ____ stored up during resting potential.
input of energy
Na-K
energy
energy
278
Action potentials spread a wave of ____ triggering the influx of na+ and the efflux of k+ creating a new action potential. Think of it like a ____ or a pulse.
depolarization
| spike
279
There is no ____ ____ in invertebrate nuerons.
myelin sheath
280
The ____ ____ allows neurons to be very small in ____ by speeding up ____ of the action potentials.
myelin sheath
diameter
conduction
281
The myelin sheath has gaps in it separated by fixed segmental lengths of ____ . These gaps, known as ____ ____ ____ , represent places on the axon not covered by ____ and therefore have membranes exposed to the extracellular space; the ____ allow for influx/efflux of ____ as the ____ does not allow for ion flux.
```
myelin
nodes of ranvier
sheath
nodes
ions
sheath
```
282
When an action potential is generated, local membrane ____ occurs.
depolarizations
283
PSPs conduct ____ .
omnidirectionally
284
Action potentials always travel in ____ ____ and ____ the terminal. Phenomenon is called ____ conduction.
one direction
terminal
orthodromic
285
____ period is when the voltage-gated channels need a little time to reset themselves.
refractory
286
An action potential releases the neurotransmitters from the terminal through ____ .
Exocytosis
287
When the action potential reaches the terminal, a new set of ____ - ____ ion channels opens, this time allowing the influx of ____ +. ____ + is needed to promote the actions of an enzyme as an ____ ____ . Once promoted, this enzyme starts the process of ____ .
```
voltage-gated
Cl+
Cl+
enzymatic cofactor
exocytosis
```
288
Exocytosis:
The synaptic vesicles ____ to the presynaptic membrane. The vesicles make physical contact with the presynaptic membrane and ____ together. Then the cell membrane-synaptic vesicle fusion point forms the ____ ____ and then pulls apart, emptying the contents of the ____ into the ____ ____ . Now the vesicle has become part of the ____ ____
```
migrate
fuse
omega complex
vesicle
synaptic cleft
presynaptic membrane
```
289
Vesicles and cell membranes are constructed of the same ____ ____ .
lipid bilayer
290
When the membrane pinches off internally and forms a new vesicle to avoid enlarging, recycling the vesicular membrane, what is that process called?
pinocytosis
291
Does a vesicle have a fixed quantity of neurotransmitters?
Yes
292
What law states that the higher rates of action potentials arriving at the terminal translate into more Ca++ influx, which in turn leads to more exocytosis of synaptic vesicles?
Rate
293
____ function to help the cell releasing the neurotransmitter monitor and regulate the amount of neurotransmitter being released.
autoreceptors
294
What is the strength of binding called?
binding affinity
295
What is the process when a neurotransmitter is deactivated by pumping them back into the pre-synaptic cell via a transporter? It actually removes the NT from the synapse and regulates the amount that binds to receptors. Also recycles NTs which reduces the amounts that need to be manufactured.
Reuptake
296
____ ____ change the chemical structures of neurotransmitters so they no longer are recognized as ligands by the receptors and can be broken down to their constituent compounds ( ____ ____ ____ ).
enzymatic degradation
| single amino acids
297
Do some neurotransmitters diffuse in the extracellular away from the synapse?
Yes
298
Name four fates of neurotransmitters
Diffuse in extracellular space
Enzymatic Degradation
Reuptake
Binding to post of pre synaptic (pre being autoreceptors)
299
____ ____ ion channels open in response to voltage (i.e. when the cell gets depolarized) where as ____ ____ channels open in response to a ligand (some chemical signal) binding to them. ... The ligand gated channels open up and allow the influx of sodium, which depolarizes the cell.
Voltage-gated
| ligan gated
