Exam 2 Slide show Muscle Tissue (Pt2) Flashcards

1
Q

Why are skeletal muscle fibers unable to undergo mitosis?

A

Because they are multinucleated (more than one nuclei)

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2
Q

During embryonic development, what fuses together to form one skeletal muscle fiber?

A

Myoblasts

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3
Q

What are able to regenerate functional muscle fibers to a limited degree by fusing with themselves or with damaged muscle fibers?

A

Satellite cells

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4
Q

Damaged skeletal muscle tissue typically undergoes ____ which is the replacement of muscle fibers by fibrous scar tissue

A

Fibrosis

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5
Q

The plasma membrane of a muscle fiber is termed what?

A

Sacrolemma

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6
Q

What is the cytoplasm of a muscle fiber

A

Sarcoplasm

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7
Q

What gives skeletal muscles its striated appearance?

A

Myofibrils

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8
Q

What is the Sarcoplasmic reticulum?

A

The smooth endoplasmic reticulum of a muscle fiber

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9
Q

What does the sarcoplasmic reticulum do?

A

Stores calcium ions, and releases them when the muscle fiber is stimulated

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10
Q

How do T-tubules open?

A

Like a cul-de-sac, only to the outside

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11
Q

What is is the calcium-binding protein inside the sarcoplasmic reticulum called?

A

Calsequestrin

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12
Q

Is the Ca++ concentration in a relaxed muscle less or higher than the cytosl?

A

higher, (10,000 times higher)

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13
Q

What are the dilated regions that flank the T-tubules?

A

Terminal cisterns

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14
Q

Two terminal cisterns flanking one T-tubule is called a

A

Triad

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15
Q

What are myofibrils made of?

A

Filaments

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16
Q

What are the two types of filaments?

A

Thick and Thin

17
Q

What are thin filaments composed of? What is their nature?

A

Actin: contractile protein

Troponin: regulatory protein

Tropomyosin: regulatory protein

18
Q

What are thick filaments composed of? What is their nature?

A

myosin; contractile protein

19
Q

What can be said about the ratio between thick and thin filaments?

A

there are two thin filaments for every thick filament

20
Q

What are the basic functional units of a myofibril?

A

Sarcomeres

21
Q

In the sarcomere, which band only has thin filaments?

A

I band

22
Q

In the sarcomere, which zone only has thick filaments?

A

H zone

23
Q

In the sarcomere, which band has both thick and thin filaments?

A

A band

24
Q

Muscle fiber proteins comprise of what three categories?

A

Contractile, Regulatory, and Structural proteins

25
Q

Which proteins are considered contractile proteins?

A

Myosin and Actin

26
Q

Which proteins are considered Regulatory proteins?

A

Troponin and Tropomyosin

27
Q

Which proteins are considered structural proteins?

A

Titin, Myomesin, Dystrophin, and Sarcolemmal proteins