Muscle Fiber Type (Exam 4)

Question 1

What are the 2 types of muscle fibers?

Answer 1

Red fibers

White fibers

Question 2

What is the superficial portion of the pig semitendinosus (eye of round) composed of?

Answer 2

80% white fibers

20% red fibers

Question 3

What is the deep portion of the pig semitendinosus (eye of round) composed of?

Answer 3

80% red fibers

20% white fibers

Question 4

What kind of muscle fiber is infraspinatus?

Answer 4

Red

Question 5

What kind of muscle fiber is rhomboideus?

Answer 5

White

Question 6

What kind of muscle fiber is complexus?

Answer 6

Red

Question 7

What kind of muscle fiber is multifidus dorsi?

Answer 7

Red

Question 8

What kind of muscle fiber is spinalis dorsi?

Answer 8

Red

Question 9

What kind of muscle fiber is longissimus dorsi?

Answer 9

White

Question 10

What kind of muscle fiber is latissimus dorsi?

Answer 10

White

Question 11

What kind of muscle fiber is trapezius?

Answer 11

Red

Question 12

What are the 2 characteristics that differ among muscle fiber types?

Answer 12

Speed of contraction

Primary type of energy metabolism

Question 13

What types of muscle fibers do muscles have?

Answer 13

All

Question 14

What types of metabolism do muscle fibers have?

Answer 14

All

Question 15

How is muscle fiber type categorized by the speed of contraction?

Answer 15

ATPase

Question 16

What is the actomyosin complex?

Answer 16

When myosin heads bind to actin molecules

Question 17

What does actomyosin ATPase activity do?

Answer 17

Get myosin ready to form cross-bridge with actin

Question 18

What is the primary protein responsible for contraction?

Answer 18

Myosin

Question 19

What is the S1 globular head extremely sensitive to?

Answer 19

pH changes

Question 20

If there is greater ATPase activity, what is speed like?

Answer 20

It is greater

Question 21

What are the 3 actomyosin ATPase activity categories?

Answer 21

Type I: slow, oxidative fiber
Type 2A: fast, oxidative fiber
Type 2B: fast, glycolytic fiber

Question 22

What is a key step in typing ATPase activity?

Answer 22

Incubating muscle fibers varying pH

Question 23

What does a pH of 4.3 do?

Answer 23

Inactivates the ATPase in fast fibers

Question 24

What does a pH of 10.4 do?

Answer 24

Inactivates the ATPase in slow fibers

Question 25

What are the ways muscle fibers can be categorized based on how muscle predominately generates energy?

Answer 25

Aerobic or anaerobic metabolism

Glycolytic or oxidative metabolism

Question 26

How is typing by metabolism done?

Answer 26

Energy generated through series of metabolic reactions catalyzed by enzymes

Question 27

What enzyme is involved in glycolytic/anaerobic metabolism?

Answer 27

Lactate dehydrogenase

Question 28

What enzymes are involved in oxidative/aerobic metabolism?

Answer 28

Succinate dehydrogenase
Isocitrate dehydrogenase
Nicotinamide adenine dinucleotide tetrazolium reductase

Question 29

How is a slow twitch, oxidative fiber classified?

Answer 29

β red

Question 30

How is a fast twitch, glycolytic fiber classified?

Answer 30

α white

Question 31

How is a fast twitch, oxidative fiber classified?

Answer 31

α red

Question 32

In the pig longissimus, what is the muscle fiber like?

Answer 32

fast twitch intermediate fiber

α white

Question 33

Look at characteristics

Answer 33

Look at characteristics

Question 34

What is an oxidative fiber like?

Answer 34

Great oxidative enzyme activity
Low glycolytic markers
Low ATPase activity
Low peak force, fatigue resistant
Tonic mode of action: slow but sustained

Question 35

What is a glycolytic fiber like?

Answer 35

Low oxidative enzyme activity
High glycolytic markers
High ATPase activity
High peak force, fatigue susceptible
Phasic mode of action: short burst but quick fatigue, not sustained