Muscle Phys III

Question 1

what protects motor units against fatigue?

Answer 1

Asynchronys Fatigue

Question 1

Why might you recruit all motor units at once?

Answer 1

power lifting

Question 2

What are the three phases of a muscle twitch

Answer 2

latent, contraction, relaxation

Question 3

period of muscle twitch before the contraction starts

Answer 3

Latent

Question 4

period of muscle twitch where cross bridge cycling occurs and tension is developing

Answer 4

contraction

Question 5

period of muscle twitch where the muscle begins to relax after a twitch

Answer 5

relaxation

Question 6

the active process of generating a force within a muscle by cross bridge activity

Answer 6

contraction

Question 7

the force exerted by muscle on an object

Answer 7

muscle tension

Question 8

the weight or force exerted by an object on a muscle

Answer 8

load

Question 9

muscle changes length BUT tension remains constant throughout

Holding a baby in a constant position

Answer 9

Isotonic Contraction

Question 10

muscle shortens - doing work

Answer 10

concentric

Question 11

muscle contracts as it lengthens

• muscle being stretched by external force, resisting stretch

Answer 11

eccentric

Question 12

tension develops at CONSTANT muscle LENGTH

• occurs in muscles that act to remain posture, stabilize joints, etc. or when the load is more than tension

(A person trying to lift up a car– muscles are contracted, but length is not changing)

Answer 12

Isometric contraction

Question 13

Sources of ATP production in muscle cells

Answer 13

1. Creatine Phosphate (CP)
2. Anaerobic Glycolysis Pathway
3. Aerobic Pathway

Question 14

A type of very fast ATP production

Problem: it is a 1:1 ratio, low product yield. Can be depleted very quickly (very short amount of time)

Answer 14

Creatine Phosphate (CP)

Question 15

in order to produce muscle contractions you need ___

Answer 15

ATP

Question 16

Why do people use creatine supplementation

Answer 16

increase creatine in muscle cells which then produces more Creatine phosphate, which yields more ATP

• good for powerlifters and sprinters
• Rate of ATP production is fast

Question 17

What is the very fast ATP production that goes through glucose rapidly

Answer 17

Anaerobic Glycolysis

Question 18

1 gulcose produces 2 ATP (low yield, but produces more than CP) what pathway is it?

Answer 18

Anaerobic Pathways

Question 19

glucose is derived from?

Answer 19

Glycogen

Question 20

fast contractions for a short amount of time.. what pathway?

Answer 20

Anaerobic Pathways

Question 21

does Anaerobic Pathways need oxygen?

Answer 21

No

Question 22

the pathway that is important in recovery

Answer 22

Aerobic pathway

Question 23

why does the Aerobic pathway need oxygen?

Answer 23

it is dependent on the cardiovascular and respiratory system

Question 24

Does Aerobic pathway have a high or low yield of ATP?

Answer 24

Very high! 1 glucose = 36 ATP BUT takes a long time

Question 25

occurs when exercising muscle can no longer respond to stimulation with same degree of contractile activity

Answer 25

muscle fatigue

Question 26

point in a graph where anaerobic glycolysis and aerobic metabolism cross

Answer 26

Anaerobic Threshold

Question 27

does creatine phosphate pathway need oxygen?

Answer 27

No

Question 28

the motion during the bicep curl when the load is raised in an arc towards the body is what type of contraction (shortening the muscle)

Answer 28

isotonic concentric

Question 29

After a dumbbell curl while lowering the dumbbell is the result of (muscle becoming long again)

Answer 29

eccentric contraction

Question 30

aiming a bow is a type of what contraction

Answer 30

isometric

Question 31

muscle has not shortened. sarcomeres shorten, generating force, but elastic elements stretch, allowing muscle length to remain the same

Answer 31

isometric contraction

Question 32

sarcomeres shorten more but, because elastic elements are already stretched, the muscle must shorten

Answer 32

isotonic contraction

Question 33

supplies about 10 seconds worth of energy and is used for short bursts of exercise, such as a 100-meter sprint

Answer 33

CP pathway

Question 34

for endurance you would use this type of ATP pathway

Answer 34

aerobic

Question 35

Adenosine inhibits supraspinal dopaminergic neurons - supraspinal dopinergic transmission is associated with increased arousal, motivation, spontaneous motor activity, and prolonged exercise time

Answer 35

central fatigue

Question 36

what are the 4 stages of cross-bridge cycling

Answer 36

1. Crossbridge Formation (activated myosin head attaches to actin) 2. Power stroke (ADP released, myosin head pivots, pulls z disc forward) 3. myosin head release (detachment from actin) 4. reactivation of myosin head (reset) z lines move closer and closer to the m line

Question 37

each myosin head allows binding sites for two things: what are they?

Answer 37

Actin (top) ATP (bottom)

Question 38

during the powerstroke phase of the crossbridge cycle what occurs?

Answer 38

ADP and Pi (phosphate group) are released. pulls the z disc closer to the m line

Question 39

ATP is binded to myosin head until what occurs?

Answer 39

until a new ATP molecule binds

Question 40

After death, our bodies can no longer replenish ATP reserves, which leads to . ATP decreased but myosin heads increase. muscles get stiffer and stiffer. muscles running out of ATP

Answer 40

Rigor Mortis

Question 41

how does a myosin head allow weight lifting - generate enough tension ?

Answer 41

it depends on teamwork. Not a single myosin head does it. Huge number of individual myosin heads undergo crossbridge cycling, which allows the ability to generate high tension force

Question 42

each thick filament pulls inward __ thin filaments

Answer 42

6 thin filaments

Question 43

importance of calcium in crossbridge cycling-- what are the 2 important proteins?

Answer 43

- tropomyosin (long protein) - Troponin (short)

Question 44

what protein covers all the myosin binding sites on actin

Answer 44

tropomyosin

Question 45

calcium binds to troponin molecules and changes the structure of tropomyosin. Myosin heads are now free and not covered and they now can perform what?

Answer 45

cross bridge