Class 2 Flashcards

1
Q

During development, all 3 types of muscle originate from where?

A

Somatic mesoderm

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

What migrates out of the somatic mesodermal germ layer to form muscle fibers

A

Myoblasts

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

Differentiation of myoblasts into their cell fate and what are believed to be highly correlated?

A

Cell lineage

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

Coelomic Graft model was used for?

A

To investigate whether muscle type differentiation is determined by myoblast cell lineage, independent of external influences

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

What is the coelom?

A

Body cavity formed during embryonic development when mesoderm is split into two layers

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

Satellite cells indicates that cell lineage is not as strong a determinant for what muscle type

A

Skeletal muscle type

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

Satellite cells are found where?

A

Between the basal lamina and plasma membrane

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

How are satellite cells activated?

A

After muscle injury or intensive exercise

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

Satellite cells fuse to what and why?

A

Fuse to themselves to create new muscle fibers or fuse to damaged muscle fibers to repair damage

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

A satellite cell can transform itself into a muscle fiber of what type?

A

Fast or slow MyHC isoforms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Nerve-evoked electrical activity is an external signal that can (-) muscle phenotype

A

Change

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

When a nerve from a fast muscle is transplanted into a slow muscle and vice versa —

A

Both re-innervated, muscles change phenotype

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

Type I motor units, receive (-) amounts of impulses delivered in (-) frequency sequences

A

High, low

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

Type II motor units, receive (-) amounts of impulses delivered in (-) frequency sequences

A

Low, high

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

Slow-to-fast muscle phenotype change

A

Difficult, or impossible

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

Fast-to-slow muscle phenotype change

A

Easy, possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why is it difficult to go from slow-to fast muscle phenotype?

A

The amount of background activity will dominate

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

Depolarization leads to what in muscle?

A

Shortening or mechanical tension

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

What is possibly more important for muscle activity? Neural or action potential?

A

Neural

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

Can muscles heal after atrophy?

A

Yes

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

Changes in muscle usage will lead to what?

A

Changes in muscle phenotype

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

Factors that can serve as messengers for muscle activity

A
  • Free intracellular Ca
  • Metabolites
  • hypoxia
  • tension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Regulation of force is a question of what?

A

Regulating fiber size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Size can be achieved by regulating three conditions that are?

A
  • number of nuclei
  • rate of protein synthesis
  • rate of protein degradation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Hypertrophy is generally accompanied by:
Addition of new nuclei
26
How are new nuclei created in muscle cells?
Satellite cells fusing with pre-existing muscle fiber
27
What is myostatin?
Member of the trans-transforming growth factor B (superfamily)
28
Myostatin function
Role during development where it acts as inhibitor of muscle growth
29
Disruption of the myostatin gene leads to
Development of grossly enlarged muscles, increase in number of fibers and fiber size
30
Activity is regulated by IGF-binding proteins acting as carriers in blood, or locally binding IGF-I to the extracellular matrix describes what?
Insulin-like growth factor I
31
What organ supplies 75% of circulating IGF-I
Liver
32
What factor has been implicated as a factor promoting hypertrophy
IGF-1
33
IGF-1 function
- increase myotube diameter - suppress proteolysis - stimulate protein synthesis - induce higher number of nuclei - promote myoblast synthesis
34
Hormone for muscles
Testosterone
35
What is the structure where axonal branches of a motor neuron form contact to a group of target muscle fibers within a single motor unit through presynaptic buttons
Motor end-plate
36
There is one somatic motor neuron per (-)
One motor unit
37
Muscles for fine control have (greater, fewer) muscle fibers per motor unit
Fewer
38
There are/is (multiple, one) muscle fibers per motor unit
Multiple
39
Axonal branches from presynaptic motor neuron form swellings that occupy depression of the muscle fiber are
Presynaptic buttons
40
Is there direct contact between presynaptic button and the postsynaptic terminal
No
41
Synaptic button that occupies a depression is known as
Primary synaptic cleft
42
Sarcolemma of the muscle fiber that forms the infolding deep junctional fold is what?
Secondary synaptic cleft
43
What kind of synapse if the neuromuscular junction?
Chemical Synapse
44
What separates the presynaptic button and the postsynaptic terminal?
Synaptic clefts
45
Synaptic vesicles are derived from the what?
Neuronal soma (cell body)
46
What step is: acetylcholine is enclosed by synaptic vesicles and transported by kinesin along the axon by anterograde axonal transport
Step 1 in synaptic transmission within the neuromuscular junction of the skeletal muscle
47
What is a neuromuscular junction?
A chemical synapse between a motor neuron and a muscle fiber
48
Acetylcholine is enclosed by the membrane-bound (-)
Synaptic vesicles
49
Where are synaptic vesicles located where?
Presynaptic terminals
50
Molecular motor proteins are what?
Kinesin
51
What is the highway of the axon?
Microtubule of the axon
52
What step is: depolarization of the axon terminal activates the voltage-gated Ca channels, increase in Ca induces exocytosis of synaptic vesicles, releasing ACh?
Step 2
53
Vesicular docking proteins are found where?
Synaptic vesicles
54
What do vesicular docking proteins allow synaptic vesicles to do?
Attach at the presynaptic terminals rich in membrane docking proteins
55
Depolarization triggers (influx, or efflux) of Ca
Influx
56
Increase in Ca concentration induces what?
Exocytosis of synaptic vesicles and releasing ACh
57
What step is AChE terminates the signal by hydrolyzing Ach into forming choline and acetyl CoA?
Step 3
58
How can Ach be enzymatically degraded and where?
In the synaptic cleft by acetylcholinesterase (AChE)
59
Where is AChE found?
Located in the post-synaptic membranes
60
Hydrolyzing ACh forms what?
Choline and acetyl CoA
61
Choline can be re-uptaked back to pre-synaptic terminal and recycled back into forming (-) by (-)?
ACh by Choline acetyltransferase
62
Kinesin-mediated that carries cargos from axon terminal toward soma are (anterograde, retrograde)
Anterograde
63
Dynein-mediated that carries cargos from axon terminal toward soma are (anterograde, retrograde)
Retrograde
64
Axonal transport requires 3 things:
- axonal cytoskeleton - motor proteins (kinesin and dynein) - hydrolysis of ATP
65
What are the 2 motor proteins?
Kinesin and dynein
66
Anterograde transport of vesicles and mitochondria is mediated by what?
Kinesin
67
Retrograde transport of a vesicle along a microtubule is mediated by what?
Dynein
68
Rabies virus is a neurotropic virus that is able to infect what?
Nerve cells
69
Rabies virus is capable of binding to the (-) and replicates in the (-)
Acetylcholine receptor, muscle tissue
70
The viral rabies particle migrated by (-) to the (-)
retrograde axonal transport to the cell body of neurons supplying affected muscle
71
Does rabies virus continue to replicate within infected neurons? Where does this occur?
Yes, in the CNS
72
Rabies virus is transported by (-) by the peripheral nerves to the (-)
Anterograde axonal transport, salivary glands
73
How is rabies transported?
Transmitted by the bite
74
A potent neurotoxin produced by clostridium tetani is what?
Tetanus
75
Tetanus uses (-) to enter the (-)
Retrograde axonal transport to enter the CNS
76
What does tetanus cause?
Spasm contraction of jaw, exaggerated reflexes, respiratory failure
77
Tetanus blocks the release of (-) a the spinal synapse
Inhibitory mediators
78
Varicella zoster causes
Chicken pox and shingles
79
Zoster virus enter the nerve body using (retrograde, anterograde) axonal transport and stay (-) in the nerves
Retrograde, dormant
80
Zoster virus reactivated by (-) and uses (anterograde, retrograde) axonal transport to move to nerve ending
Stress, anterograde
81
Shingles starts at the muscle and then is transported to the skin (T/F)
True
82
Curare produces what symptoms?
Muscle paralysis
83
Curare bind to Ach receptor and prevents binding of Ach to the (-)
Nicotinic acetylcholine receptors
84
Nicotinic acetylcholine receptors are located where?
Postsynaptic membrane
85
Botulinum toxin is an exotoxin that prevents the release of (-) at the (-)
Acetylcholine at the presynaptic terminal
86
Botulinum toxin produces what symptoms?
Muscle paralysis and dysfunction of the autonomous nervous system
87
Myasthenia gravis is an autoimmune disease with antibodies against (-) which
Ach receptors which prevent binding of Ach to the nicotinic acetylcholine receptors
88
Myasthenia gravis symptoms
Muscle weakness
89
Lambert-Eaton myasthenic syndrome is an autoimmune disease with antibodies against (-)
Voltage-gated Ca channels
90
Lambert-Eaton myasthenic syndrome reduces (-) into intracellular space
Calcium
91
Lambert-Eaton myasthenic syndrome symptoms
Muscle weakness