Exam 2 Slide show Muscle Tissue (Pt2)

Question 1

Why are skeletal muscle fibers unable to undergo mitosis?

Answer 1

Because they are multinucleated (more than one nuclei)

Question 2

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

Answer 2

Myoblasts

Question 3

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

Answer 3

Satellite cells

Question 4

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

Answer 4

Fibrosis

Question 5

The plasma membrane of a muscle fiber is termed what?

Answer 5

Sacrolemma

Question 6

What is the cytoplasm of a muscle fiber

Answer 6

Sarcoplasm

Question 7

What gives skeletal muscles its striated appearance?

Answer 7

Myofibrils

Question 8

What is the Sarcoplasmic reticulum?

Answer 8

The smooth endoplasmic reticulum of a muscle fiber

Question 9

What does the sarcoplasmic reticulum do?

Answer 9

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

Question 10

How do T-tubules open?

Answer 10

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

Question 11

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

Answer 11

Calsequestrin

Question 12

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

Answer 12

higher, (10,000 times higher)

Question 13

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

Answer 13

Terminal cisterns

Question 14

Two terminal cisterns flanking one T-tubule is called a

Answer 14

Triad

Question 15

What are myofibrils made of?

Answer 15

Filaments

Question 16

What are the two types of filaments?

Answer 16

Thick and Thin

Question 17

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

Answer 17

Actin: contractile protein

Troponin: regulatory protein

Tropomyosin: regulatory protein

Question 18

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

Answer 18

myosin; contractile protein

Question 19

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

Answer 19

there are two thin filaments for every thick filament

Question 20

What are the basic functional units of a myofibril?

Answer 20

Sarcomeres

Question 21

In the sarcomere, which band only has thin filaments?

Answer 21

I band

Question 22

In the sarcomere, which zone only has thick filaments?

Answer 22

H zone

Question 23

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

Answer 23

A band

Question 24

Muscle fiber proteins comprise of what three categories?

Answer 24

Contractile, Regulatory, and Structural proteins

Question 25

Which proteins are considered contractile proteins?

Answer 25

Myosin and Actin

Question 26

Which proteins are considered Regulatory proteins?

Answer 26

Troponin and Tropomyosin

Question 27

Which proteins are considered structural proteins?

Answer 27

Titin, Myomesin, Dystrophin, and Sarcolemmal proteins