Musculoskeletal Development II Flashcards

1
Q

What are the 4 stages in the differentiation of skeletal muscle tissue? Describe 3/4 stages

A

Myogenic cells:

  • Originate in somites
  • Resemble mesenchymal cells
  • Mitotic cells

Myoblasts:

  • Derived from myogenic cells
  • Postmitotic

Myotubes:
-Formed when Myoblasts line up and adhere to each other

Muscle Fibers

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

What 2 factors keep Myogenic cells in the mitotic state?

A

FGF

TGF- beta

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

What do Myotubes require?

A

Calcium-dependent CAMs

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

What are Myotubes involved in?

A

mRNA and protein synthesis

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

What characterizes Myotubes?

A

The appearance of Actin, Myosin, Troponin, and Tropomyosin

Nuclei moving to the periphery

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

Where do Satellite cells attach?

A

To myotubes before the basal lamina is laid down

Located between the sarcolemma and the basal lamina of the myofiber

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

What is the function of satellite cells in terms of muscle growth?

A

Act as stem cells

Can become mitotic in times of stress:
- When Hepatic growth factor binds to the C-Met receptor

Gives rise to myogenic precursor cells to replace damaged skeletal muscle

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

Myotubes can be broken down into primary and secondary myotubes. When do primary myotubes form?

A

After fusion of early (embryonic) myoblasts

This differentiation occurs before innervation

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

Myotubes can be broken down into primary and secondary myotubes. When do secondary myotubes form?

A

Formed alongside primary myotubes from late (fetal) myoblasts

This differentiation occurs after innervation

*Smaller than primary

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

What causes myogenic cells to lose their mitotic capability?

A

p21- produced by myogenic cells in response to myogenic-regulatory factors, MyoD family

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

Describe myogenic-regulatory factors, MyoD family

A

Able to convert non-muscle cells to cells capable of expressing muscle proteins

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

What is the pathway from myogenic precursors to myofibers?

A

Pax-3 and Myf-5 separately activate MyoD and cause myogenic cells to become myoblasts

Myoblasts express myogenin

Myogenin results in the expression of myotube genes of Myf-6

Myf-6 leads to the expression of Myofibers

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

Limb muscles arise from what?

A

The ventrolateral demomyotome

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

Tendons of limb muscles arise from what?

A

Lateral plate of the mesoderm

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

Where is cardiac muscle derived from?

A

Splanchnic mesoderm

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

Early cardiac muscle does not express what?

17
Q

Cardiac muscle cells remain as _______ cells and attach to each other via _______ ______

A

Mononucleated

Intercalated Discs