EXAM 1 Study Guide Flashcards
(177 cards)
1
Q
Wide dark band of thick filaments in the center of the sarcomere
A
A-band
2
Q
During the action potential, you won’t get another action potential no matter how strong a second stimulus is.
A
absolute refractory period
3
Q
Acetylcholine is found is the (PNS/CNS/both)
A
both
4
Q
Neurons that use acetylcholine are known as
A
cholinergic neurons
5
Q
This chemical acts at muscarinic (G-protein coupled) receptors
A
Acetylcholine
6
Q
This chemical acts at nicotinic (ion channels) receptors
A
Acetylcholine
7
Q
Where are nicotinic receptors found?
A
at the neuromuscular junctions of skeletal muscules.
8
Q
Where does the degradation of ACh occur?
A
synaptic cleft
9
Q
What enzyme is responsible for the degradation of ACh?
A
acetylcholinesterase (AChE)
10
Q
Degradation of ACh is as follows
Acetylcholine -> ______ + _______
A
acetate + choline
11
Q
What inhibits acetylcholinesterase and what is the result of the inhibition?
A
Sarin (Nerve Gas); causes a buildup of ACh in the synaptic cleft.
12
Q
Interconnected proteins that anchor actin thin filaments
A
Z=line
13
Q
A cross-sectional view of a skeletal muscle fiber through the H zone reveal the presence of what?
A
Myosin, but no actin
14
Q
formed by globular actin that is polymerized into a single stand called filamentous actin
A
Actin
15
Q
Each actin has _______ binding sites
A
myosin
16
Q
Why are myosin binding sites important on actin?
A
They are important in developing muscle contraction
17
Q
A double helix of F-actin is called:
A
Actin strand
18
Q
What are the two important regulatory molecules on actin filaments
A
Troponin and Tropomyosin
19
Q
A long fibrous molecule that blocks the myosin binding sites
A
Tropomyosin
20
Q
A complex of three different proteins that binds tropomyosin, actin, and Ca2+
A
Troponin
21
Q
What three different proteins binds to troponin?
A
Actin, Tropomyosin, and Ca2+
22
Q
What does Ca2+ binding to troponin do?
A
shifts tropomyosin away from the myosin binding sites
23
Q
True or False
Action potentials are generally slow and may repeat at frequencies of several hundred per minute.
A
False
generally fast and may repeat at frequencies of several hundred per second
24
Q
The ability to generate action potentials is known as:
A
excitability
25
A large change in membrane potential is known as
an action potential
26
Also known as an "all or none" response
action potential
27
In order to cause an action potential, a cell must utilize (_at least one/ several)_ type(s) of ion channel(s).
several
28
What type of channels often serve as the initial stimulus for an action potential?
ligand-gated channels and mechanically gated channels
29
What type of channel gives the membrane the ability to undergo action potential by allowing the rapid depolarization and repolarization phases of the response?
Voltage gated channels
30
channels that conduct ions such as Na+, K+, Ca2+, or Cl- are referred to as:
voltage gated channels
31
**Mechanisms of Neurotransmitter release:**
What is the active zone?
the release region of the presynaptic membrane; SNARE proteins dock vesicles in this region
32
the release region of the presynaptic membrane; SNARE proteins dock vesicles in this region
Active zone
33
What three ways can muscle fiber form ATP?
1. Creatine phosphate
2. Anaerobic metabolism
3. Aerobic metabolism
34
What supplies the energy for muscle contraction
ATP
35
Without ___ no contraction can take place
ATP
36
oxidative phosphorylation occurs through (_aerobic/ anaerobic)_ metabolism
aerobic
37
Glycolysis occurs through (_aerobic/ anaerobic)_ metabolism
anaerobic
38
(_afferent/efferent/ Inter)_ neurons transmit information from peripheral system to CNS
afferent
39
(_afferent/ efferent/ Inter)_ neurons cell body is often found in ganglion.
afferent
40
a collection of cell bodies is called a :
ganglion
41
_(afferent/ efferent/ Inter)_ neurons are the most numerous type of neuron.
interneurons
42
_(afferent/ efferent/ Inter)_ neurons are all located in the CNS
Interneurons
43
_(afferent/ efferent/ Inter)_ neurons process afferent abd efferent signals.
interneurons
44
_(afferent/ efferent/ Inter)_ neurons are key in reflexes
Interneurons
45
_(afferent/ efferent/ Inter)_ neurons transmit information from the CNS to the peripheral system.
Efferent
46
_(afferent/ efferent/ Inter)_ neurons transmit information from CNS to effector cells such as muscle or gland
efferent
47
_(afferent/ efferent/ Inter)_ neurons cell body is located in the CNS
efferent
48
_(afferent/ efferent/ Inter)_ neurons soma in CNS
efferent
49
Small interneurons in the brain that dampen activity within neural circuits
GABA neurons
50
Somatic efferent neurons are also known as:
motor neurons
51
What organic chemical is directly correlated with Alzheimer's Disease?
Acetylcholine
52
The degradation of neurons associated with the ACh system:
Alzheimer's Disease
53
Associated with a decreased amount of ACh in certain areas of the brain
Alzheimer's disease
54
The loss of postsynaptic neurons that responded to ACh:
Alzheimer's disease
55
Results in declining language and perceptual abilities, confusion, and memory loss:
Alzheimer's disease
56
The sixth-leading cause of death in the US
Alzheimer's disease
57
Astrocytes can be found in the (_CNS/PNS)_
CNS
58
This is most abundant in the Glial cell:
Astrocytes
59
Define ***primary active transport***
The direct use of ATP in ion channels
60
What is an autocrine substance?
it acts on the same cell that secreted the substance
61
What is paracrine substance?
They target cells in close proximity to site of release of paracrine substance
62
Where are paracrine substances found
Local Cells
63
Where are autocrine substances found?
Local Cells
64
\_\_\_\_ from many neurons are packaged together along with connective tissues to form a nerve
Axons
65
**Structure of a Neuron:**
Sends information away from the cell body by impulses called action potentials
Axon
66
**Structure of a Neuron:**
Connected to the soma at the axon hillock
Axon
67
**Structure of a Neuron:**
Connected to the soma at the initial segment
Axon
68
**Structure of a Neuron:**
Does not branch, may have collaterals
Axon
69
**Structure of a Neuron:**
has axon terminals
Axons
70
**Structure of a Neuron:**
Releases neurotransitter
Axon Terminal
71
This membrane transports glucose out of the cell
basolateral membranes
72
This membrane transports glucose into the cell
apical membrane
73
Interferes with SNARE proteins at excitatory synapses that activate muscles
Clostridium botulinum bacili toxin
74
\_\_\_\_\_\_\_\_ is characterized by muscle paralysis
botulism
75
Used to treat facial wrinkles, severe sweating, and uncontrollable blinking
botulinum toxin (Botox)
76
**Structure of a Neuron:**
Receives information, direct information towards the cell body
Dendrites
77
**Structure of a Neuron:**
Short branching
Dendrites
78
**Structure of a Neuron:**
Axons can synapse here
Dendrites
79
Composed of the brain and the spinal cord
Central nervous system (CNS)
80
What glial cells are found in the CNS
* Astrocytes
* Ependymal cells
* Microglia
* Oligodendrocytes
81
This cells function in the CNS is to guide developing neurons into making the correct connections
Astrocytes
82
This cells function in the CNS is to modulate synaptic activity
astrocyte
83
This cells function in the CNS is to help maintain the proper electrolyte composition of the extracellular fluid
astrocyte
84
This cells function in the CNS is to protect against toxic substances by forming the Blood-Brain barrier
Astrocyte
85
This cells function in the CNS is to form an epithelia that lines portions of the ventricle system of the brain and the spinal cord
Ependymal Cells
86
This cells function in the CNS is to produce cerebral spinal fluid (CSF)
ependymal cells
87
This cell in the CNS is ciliated
ependymal cells
88
Why are ependymal cells ciliated?
to help in the movement of cerebral spinal fluid
89
This cell in the CNS is small and elongated with short irregular processes.
Microglia
90
This cells function in the CNS is to respond to infection
microglia
91
This cells function in the CNS is to protect the CNS by removing foreign material and the remains of dead or injured cells
microglia
92
This cells function in the CNS is to perform phagocytosis
microglia
93
This cells function in the CNS is to protect against oxidative stress
microglia
94
This cell in the CNS is a large cell body, thin-flat processes that wrap repeatedly abound the portions of the axon
oligodendrocytes
95
This cells function in the CNS is to produce a myelin sheath around the axons of neurons
oligodendrocytes
96
What is the purpose of myelination
allows for rapid transmission of action potentials (electrical signal within the neuron)
97
**True or False**
Each oligodendrocyte can myelinate multiple axons
True
98
**True or False**
Neuron outnumber glial cells 10 to 1 in the CNS
False
Glial cells outnumber neurons 10 to 1
99
Serotonin is a (_CNS/PNS_) neurotransmitter
CNS
100
Chemical synapses ar the most common in \_\_\_\_\_\_\_.
neurons
101
What are the different types of neuronal chemical synapses:
* Neuron to neuron
* Neuron to effector cell (neuromuscular junction)
* Neuron to non-neuron or non-muscle cell
102
\_\_\_\_\_\_\_\_\_\_ neurons rlease neurotransmitter from their axon terminals
Presynaptic
103
**Anatomy of a chemical synapse:**
has a high density of membrane potentials
postsynaptic density
104
**Anatomy of a chemical synapse:**
Has 10-20 nm extracellular space
synaptic cleft
105
**Anatomy of a chemical synapse:**
Prevents direct propagation of current
synaptic cleft
106
**Anatomy of a chemical synapse:**
a chemical messenger released from the presynaptic axon terminal
neurotransmitter
107
These cells connect, anchor, and support the structures of the body
Connective Tissue cells
108
A deadly arrowhead poison used by indigenous peoples of South America
Curare
109
This binds to ACh receptors. It does NOT open their ion channels and acetylcholinesterase does NOT destroy it
Curare
110
ACh cannot bind to receptor when occupied by this chemical
Curare
111
This chemical can cause death by asphyxiation
Curare
112
What are the four steps of ***cross-bridge cycling***
## Footnote
******
1. Attachment of a cross-bridge to a thin filament (Activated myosin head binds to actin, forming a cross-bridge)
2. movement across the cross bridge
3. Detachment of the cross bridge (Let it go)
4. Energizing the cross bridge again so that it can attach to the thin filament
113
During the cross-bridge cycle, when is the myosin head in high energy form?
when the ATP that is attached to the myosin is hydrolyzed from ATP to ADP + Pi
114
The (_high/low_) energy form of myosin has a high affinity for actin
High
115
The (_high/low)_ energy form of the myosin head has No ATP, ADP, or Pi bound to itself and remains bound to actin
low
116
What does the cross-bridge cycle rely on?
ATP hydrolysis
117
Explain the figure at each step of the cross-bridge cycle
1. Cross-bridge binds to actin
2. Cross-bridge moves
3. ATP binds to myosin, causing cross-bridge to detach
4. Hydrolysis of ATP energizes cross-bridge
118
Activation of Cross-bridge cycling is by
(_Na+ / K+ / Ca2+)_
Ca2+
119
What is the role of Ca2+ in cross-bridge cycling?
1. Ca2+ binds to troponin
2. Tropomyosin exposes the cross-bridge binding site on actin
3. Cross-bridge binds to actin and generates force
120
Low cytosolic Ca2+ = (_activated/relaxed)_ muscle
relaxed
121
High cytosolic Ca2+ = (_activated/relaxed)_ muscle
activated
122
**Mechanism of cytosolic increase in Ca2+**
Where does the Ca2+ come from?
The sarcoplasmic reticulum within the muscle fiber
123
Once an action potential is triggered in the muscle, it travels along the __________ and into the \_\_\_\_\_\_\_\_\_\_
sarcolemma; T-tubules
124
Where are T-tubules located?
Between the terminal cisternae of the sarcoplasmic reticulum
125
A voltage-gated Ca2+ channel located inside a
t-tubular system
dihydropyridine receptors (DHPR)
126
DHPR directly contacts and opens these Ca2+ channels located on the sarcoplasmic reticulum
ryanodine receptors
127
What are considered the *_cargo trucks_* in **axonal transport**
Kinesin and dynein
128
What is considered the *_road_* in **axonal transport**
microtubules
129
(_Kinesin/Dynein)_ transport is mainly retrograde (towards the cell body)
Dynein
130
(_Kinesin/Dynein_) transport is mainly anterograde
(from cell body towards axon terminal)
Kinesin
131
Which type of axonal transport moves processively (step by step)
Kinesin transport
132
What type of _cargo_ is carried in **kinesin transport**
nutrients, neurotransmitter-filled vesicles
133
What type of *_cargo_* is carried in **d****ynein****transport**
recycled membrane vesicles, growth factors
134
creatine phosphate provides (_slow/fast)_ energy production
fast
135
how long does the energy from creatine phosphate last?
10-15 seconds
136
What are the 3 major phases of muscle twitch?
1. Latent period
2. Contraction Phase
3. Relaxation Phase
137
**Name the major muscle phase:**
The period of time from the action potential to the onset of contraction
Latent period
138
**Name the major muscle phase:**
The action potential sweeps across the sarcolemma
latent period
139
**Name the major muscle phase:**
Ca2+ ions are released from the sarcoplasmic reticulum
Latent Period
140
**Name the major muscle phase:**
Lasts about 2 seconds
Latent phase
141
**Name the major muscle phase:**
This is the time that tension is developing due to the cross-bridge cycling
Contraction Phase
142
**Name the major muscle phase:**
Ca2+ binds to troponin revealing binding sites for myosin on the actin filament
Contraction Phase
143
**Name the major muscle phase:**
Cross-bridges form
Contraction phase
144
How long does the contraction phase last?
10-100 msec
145
**Name the major muscle phase:**
This is the time the tension is decreasing
relaxation phase
146
**Name the major muscle phase:**
Ca2+ is actively transported back into the sarcoplasmic reticulum
Relaxation Phase
147
**Name the major muscle phase:**
Myosin binding sites are covered up by tropomyosin
Relaxation phase
148
How long does the relaxation phase last?
10-100msec
149
What's the contraction time of fast twitch fibers?
~10 msec
150
What's the contraction time of slow twitch fibers?
~100 msec or longer
151
Define ***Isometric twitch***
Twitches that generate tension but do not shorten the muscle (constant length)
152
When the load is greater than the force generated by the muscle, an (_isometric/isotonic)_ twitch occurs
isometric
153
Define ***Isotonic twitch***
the muscle contracts with a greater force than resistance; causing the muscle to shorten.
154
Occurs when the load is greater than the tension
Isometric twitch
155
Trying to lift a car with your arms or maintaining posture is an example of:
Isometric twitch
156
occurs when the load is less than the tension
isotonic twitch
157
**Name the twitch contraction:**
Has a short latent period
Isometric twitch
158
**Name the twitch contraction:**
Has a long period of force generation
Isometric twitch
159
**Name the twitch contraction:**
Tension begins to increase as soon as the first cross-bridge attaches
isometric twitch
160
**Name the twitch contraction:**
Latent period is only due to the excitation-contraction coupling delay
isometric twitch
161
**Name the twitch contraction:**
Longer latent period
isotonic twitch
162
**Name the twitch contraction:**
Latent period includes both times for:
1) excitation-contraction coupling and
2) the extra time it takes to accumulate enough attached cross-bridges to lift the load off of the platform
Isotonic twitch
163
**Name the twitch contraction:**
The period of muscle shortening is shorter
Isotonic twitch
164
What are the characteristics of twitch dependent on?
1. The type of contraction (isotonic or isometric)
2. The magnitude of the load being lifted
165
The force generated by an individual muscle fiber depends on the number of active \_\_\_\_\_\_\_.
cross-bridges
166
The force generated by an individual muscle fiber depends on the number of active cross-bridges. **The number of cross-bridges is influenced by:**
1. Frequency of stimulation
2. Fiber diameter
3. Length of fiber
167
The whole muscle contraction is dependent on the number of ______ stimulated.
fibers
168
A single action potential in a skeletal muscle fiber lasts ______ ms and the twitch lasts up to ______ ms.
1-2 ; 100
169
When a stimulus is applied before a fiber has completely relaxed from a twitch, it induces a contractile response with a peak tension greater than that produced in a single twitch, This is called:
Summation
170
The Tension vs Time graph below is an example of:
Summation
171
**True or False:**
Postsynaptic potential summation observes the effect if additional attached cross-bridges
False
**_Summation_** (Frequency- Tension Relation) observes the effect of additional attached cross-bridges.
172
**True or False:**
Postsynaptic potential summation involves additive voltage effects on the membrane
True
173
A maintained contraction in response to repetitive stimulation is known as a:
Tetanus (tetanic contraction)
174
The Tension vs Time graph below is an example of:
a tetanus (tetanic contraction)
175
What is the significance of muscle fiber diameter in a whole muscle contraction?
It influences the force-generating capacity of a fiber
176
The (_smaller/larger)_ the fiber, the greater the force
larger
177
The force generated by a muscle contraction also depends on the length of the _______ within a muscle before contraction occurs
sarcomeres
