Chapter 2

Question 1

describe the order of a muscle cell starting with muscle fascicle.

Answer 1

muscle fascicle –> muscle fiber –> myofibril –> sacromeres –> actin/myosin

Question 2

How does a muscle fiber diameter affect force?

Answer 2

the larger the diameter, the larger the force

Question 3

define hypertrophy

Answer 3

increase in muscle size

Question 4

define hyperplasia

Answer 4

cell splitting into two cells (increase in number)

Question 5

What are intermediate proteins?

Answer 5

they are helper proteins

Question 6

Order the different muscle compartments, mysium. largest–> smallest

Answer 6

epimysium, perimysion, endomysium

Question 7

other name for thick and thin filament?

Answer 7

myosin, actin

Question 8

Calcium released from AP will bind to troponin and pull

Answer 8

true

Question 9

Role of titin?

Answer 9

“sticky spring”, thought to be used for support

Question 10

Describe process of translation and transcription.

Answer 10

DNA is transcribed into RNA in the nucleus, the RNA is the brought into cytoplasm, ribsomes can then translate it into usable protein

Question 11

where is a satellite cell located?

Answer 11

between plasmalemma and basement membrane

Question 12

Function of satellite cells?

Answer 12

involved in the growth and development of skeletal muscles

Question 13

when are satellite cells usually activated?

Answer 13

in reponse to training or injury

Question 14

what happens when a satellite cell divides?

Answer 14

splits into a mature muscle cell and a satellite cell that replaces the old one

Question 15

Describe the ER and ribsomones of a muscle cell

Answer 15

poorly developed ER bc it keeps the protein for itself, a lot of ribosome

Question 16

T/F muscle cell requires large activation to create protein

Answer 16

False, very sensitve to movement

Question 17

Explain sliding filament theory?

Answer 17

myosin has two binding sites for ATP and actin
calcium is released from the SR, binds to troponin, tropomyosin is removed from actin
myosin binds to actin. Myosin released ATP and grabs actin, pulls disks closer together

Question 18

describe relaxation after filament theory?

Answer 18

requires energy, myosin releases actin, ATP hydrolyzed and myosin resets. Calcium is removed from sarcomplasm by SERCA

Question 19

how long is a single contraction period? how much of that is needed for activation v.s actual movement?

Answer 19

100 msec. 5 msec needed for activation. 95 needed for movement

Question 20

Describe the three phases of a twitch?

Answer 20

Latent period is when the signal is released, action potential is generated, calcium released, troponin/ tropomyiosin action
Contraction is the generation of tension and formation of cross-bridges
Relaxation is when the muscle returns to its normal length

Question 21

define temporal summation?

Answer 21

potentials come in at different times but for the same location

Question 22

what happens to calium exposure during temporal summation?

Answer 22

increase in exposure causing more force

Question 23

Phases of temporal summation?

Answer 23

twitch. unfused tetanus. fused tetanus. fatigue

Question 24

what is a twitch?

Answer 24

smallest contractile respone of a muscle fiber to a stimulus

Question 25

Motor units vary is force depending on frequency. T/F

Answer 25

true

Question 26

what is tentanus?

Answer 26

peak force

Question 27

what is rate coding?

Answer 27

the rate at which a motor unit is firing. determining the force being created

Question 28

what is spatial summation?

Answer 28

signals coming from different locations at the same time

Question 29

T/F units are recruited from large to small

Answer 29

false, small units will be recruited first

Question 30

what is the main difference in force generation between untrained and trained individuals

Answer 30

untrained individuals rely on spatial summation for force generation. Trained individuals rely on both spatial summation and rate coding

Question 31

what does it mean to be an optimal sacromere length?

Answer 31

length that has the best overlap of thick and thin filaments. bodys natural resting length maximizes ability to generate force

Question 32

What is the optimal sacromere length range?

Answer 32

2.0-2.25 micrometers

Question 33

What does the force-velocity relationship measure?

Answer 33

affect of speed on force applied

Question 34

with a concentric contraction what happens to force when speed increases? eccentrically?

Answer 34

decrease, increases

Question 35

why does the force-velocity relationship occur?

Answer 35

with a slower contraction speed, there is more time for cross- bridge formation

Question 36

significance of length tension- velocity

Answer 36

at high velocity, little force is developed regardless of length. at low velocity force is developed related to length

Question 37

how many forms does muscle fiber come in?

Answer 37

1 slow form, 3 fast form (IIA,X,B)

Question 38

rank the fiber forms from fastest to slowest

Answer 38

IIB --> IIX --> IIA --> Ib

Question 39

what are IIAX fibers?

Answer 39

display IIA in trained individuals and IIX in untrained.

Question 40

is a IIX a fit or non-fit fiber?

Answer 40

non-fit

Question 41

why does Rhabdomyolysis occur?

Answer 41

after intense physical activity the skeletal muscle will break down causing a loss of myoglobin and cellular contents in urine