Chapter 17: Muscle Skeletal system

Question 1

Characteristics of Muscle fibers

Answer 1

Irritability: ability to receive stimuli
Contractability: shortening in muscle length
Extensibility: ability to stretch or lengthen
Elasticity: ability to respond to resting length after being stretched

Question 2

Muscle fiber structure

Answer 2

Epimysium -> Fasicle -> Muscle Fiber -> Myofibrils

Question 3

What cover fasicle? muscle fibers? myofibrils?

Answer 3

perimysium
endomysium
sarcolemma

Question 4

Contents of a muscle fiber?

Answer 4

Nuclei/ Mitochondrion
SR and T-tubules
Myofibrils
Sarcolemma

Question 5

Contents of myofibril

Answer 5

sacromeres

Question 6

What is sacromere composed of?

Answer 6

Actin/ Myosin
Z disc, M line (central line of sarcomere)
H zone: only myosin
A band: overlapped myosin and actin
I band: only actin

Question 7

What are the components of actin?

Answer 7

troponin (C and I) and tropomyosin

Question 8

What is responsible for conduction of action potential in muscle fibers?

Answer 8

T- tubules, run deep from epimysium to myofibrils

Question 9

What trigger the release of Ca2+? Where does it release?

Answer 9

action potential conduction in T-tubules
Sarcoplasmic reticulum (SR)

Question 10

When does the power stroke of myosin occur?

Answer 10

the release of ADP and P(i)

Question 11

How is the length of myosin and actin filament during muscle contraction?

Answer 11

they are not changing but sarcomeres do

Question 12

Where is in the sarcomere there are more intermediate elastic filament? What does it do?

Answer 12

from Z-disc to central line

help sarcomere to contract

Question 13

What are the muscle fibers type? and each motor neuron type

Answer 13

Slow oxidative (type 1 alpha motor neuron)
Fast glycolytic (type 2 alpha motor neuron)
Fast oxidative glycolytic (type 2 alpha motor neuron)

Question 14

What type of muscle fiber that can swing between SO and FG?

Answer 14

FOG

Question 15

How is the force generate by FG and FOG

Answer 15

they are the same

Question 16

What are the chacteristics of slow oxidative fiber?

Answer 16

high mitochondrion, capilaries, myoglobin, oxidative enzyme

high triglyceride and low glycogen

Question 17

What are the characteristics of FG?

Answer 17

high phosphate creatine store, high glycogen,

myosin-ATPase

Question 18

How is the size of motor neuron of FG and FOG compared to SOG?

Answer 18

they are larger in size and well myelinated

Question 19

What muscle fiber type can recruit more motor neurons than the other?

Answer 19

FOG and FG

Question 20

How is the proportion of slow oxidative fiber in female compare to male?

Answer 20

female has higher slow oxidative fiber than male

Question 21

How is the proportion of fast twitch fiber in both sex?

Answer 21

they are the same

Question 22

What is the characteristic of myosin?

Answer 22

they contain 2 heads and a rod-like tail

Question 23

The process whereby the electrical events in the sarcolemma are linked to
movement in the myofibril is called?

Answer 23

excitation-coupling reaction

Question 24

The fast and slow property of muscle fibers depends on what subcategory

Answer 24

alpha motor neurons type and the enzyme activity of ATPase

Question 25

What is required for both activation of myosin head and detachment of myosin and actin?

Answer 25

ATP

Question 26

How is the fiber type relative to the motor unit?

Answer 26

Only one type of fiber in one motor unit

Question 27

How many percent muscles account for male and female?

Answer 27

40-45%

23-25%

Question 28

What is the different name for skeletal muscle fiber?

Answer 28

extrafusal muscle fibers