Muscle II

Question 1

What determines the speed of contraction/

Answer 1

Myosin ATPase

Question 2

What determines the speed of relaxation?

Answer 2

Ca-ATPase pump

Question 3

Calcium is pumped back into SR at the rate of?

Answer 3

Ca / ATP

Question 4

The feet region is between?

Answer 4

Polarized T-tubule membrane and SR membrane

Question 5

DHP

Answer 5

Slow voltage-sensitive Ca channel on T-tubule membrane

Question 6

Ryanodine

Answer 6

Ca release channel on SR membrane

Question 7

3 steps of muscle contraction

Answer 7

1. Attachement
2. Cockin
3. Power stroke and detachment

Question 8

What happens when Ca releases from SR?

Answer 8

Myosin attaches to actin

Question 9

What is “cocking”?

Answer 9

ATP binds to muscle ATP complex → chemical energy is converted to mechanical

Question 10

What is “power stroke”?

Answer 10

ATP → ADP + Pi

Thin filament is pulled over the thick filament

Question 11

Rate limiting factor of muscle contraction

Answer 11

Power stroking and detachment

Question 12

The 3 events of contraction

on the test so know it apparently

Answer 12

1. Electrical event
2. Chemical event
3. Mechanical event

Question 13

2 types of series elastic elements

Answer 13

1. Tendon

2. Hing region

Question 14

3 types of parallel elastic elements

Answer 14

1. Sarcolemma
2. Blood vessels and ln.
3. CT

Question 15

Contractile elements = ?

Answer 15

Sarcomere

Question 16

2 types of muscle contraction

Answer 16

1. Isometric

2. Isotonic

Question 17

If force of a weight > force produced by m. → ?

Answer 17

Weight doesn’t move

Question 18

If force of a weight

Answer 18

Muscle shortens and weight moves

Question 19

What is the difference between isometric and isotonic contraction?

Answer 19

The contractile elements get shorter, but the elastic elements only stretch during isometric

Question 20

Active tension is due to?

Answer 20

Contractile elements

Question 21

Passive tension is due to?

Answer 21

1. Sarcolemma
2. CT
3. Blood vessels and nn.
4. Hinge region of myosin

Question 22

Is tension important of muscle fiber type?

Answer 22

Yes. It’s very important to know this apparently.

Question 23

Total force production is dependent on?

Answer 23

Cross-sectional area of muscle

Question 24

l(0) maximizes?

Answer 24

Active sites of myosin-actin binding and cross-bridge interaction

Question 25

Result of exercise training on cardiac myocyte?

Answer 25

Gets longer

Question 26

Result of pressure overload on cardiac myocyte?

Answer 26

Myocyte gets thicker

Question 27

Velocity = ?

Answer 27

Distance / time

Question 28

“Slope” on a graph with time and distance

Answer 28

Velocity of contraction

Question 29

Velocity of contraction changes as a function of?

Answer 29

Weight (larger velocity → lighter weight)

Question 30

V(0) = ?

Answer 30

Maximal velocity of contraction

Question 31

Maximal velocity of contraction is dependent on?

Answer 31

Cross-bridge cycline rate

Question 32

P(0) = ?

Answer 32

Isometric contraction

Question 33

Isometric contraction is dependent on?

Answer 33

Number of cross-bridges between actin and myosin

Question 34

Cross-bridge cycling rate (velocity) is affected by?

Answer 34

1. Type of myosin ATPase (fast or slow)
2. Temp
3. pH

Question 35

Force is affected by?

Answer 35

1. Sarcomere length + # of cross-bridges

2. Degree of activation

Question 36

What does “degree of activation” mean in regards to force?

Answer 36

More Ca released → more cross-bridges formed

Question 37

What is temporal association?

Answer 37

Frequency of firing of an alpha-motor neuron

Question 38

What is spatial summation?

Answer 38

Recruitment of different alpha-motor neurons

Question 39

Greater firing frequqnecy of motor n. is correlated with?

Answer 39

Greater frequency of action potential