lecture 5- muscle mechanisms

Question 1

antagonistic muscle

Answer 1

flexors & extensors

Question 2

fluid pressure on muscles

Answer 2

distant muscles push & extend on contracted muscle

Question 3

2 factors that allow for graded contraction

Answer 3

of muscle fibers & tension

Question 4

motor unit

Answer 4

1 neuron + fibers it innervates

Question 5

motor unit recruitment

Answer 5

more motor units = stronger contraction

Question 6

small vs large motor units

Answer 6

small - precise - eyes/fingers
large- powerful, quads

Question 7

how is muscle fatigue avoided?

Answer 7

if contractions are maximized aschrononously

Question 8

what does contraction frequency depend on?

Answer 8

and length of the motor units involved

Question 9

twitch summation

Answer 9

increasing frequencies to cause a tetanus response

Question 10

tetanus

Answer 10

repeated stimulation 3-4x stronger than a twitch

Question 11

T or F: tetanus has more tension than twitch

Answer 11

T

Question 12

what are 2 factors that affect tetanus?

Answer 12

1. steady state of high Ca levels during active contraction
2. stretching time
   - if restimulated = slower relaxation = greater tension build up - like elastic band

Question 13

T or F: muscles don’t stretch more than 30%

Answer 13

T

Question 14

resting vs stretching muscle cross bridges

Answer 14

resting- max # of cross bridges

stretching- fewer cross bridges

Question 15

tension transmission

Answer 15

tension -> connective tissue -> bone

Question 16

how many bones is 1 muscle attached to

Answer 16

2

Question 17

attachment site

Answer 17

moves with stationary muscle

Question 18

insertion site

Answer 18

moves with moving muscle

Question 19

2 types of contractions

Answer 19

isotonic & isometric

Question 20

isotonic contraction

Answer 20

muscle tension remains constant as muscle changes length
- work is done

Question 21

isometric contraction

Answer 21

muscle is prevented from shortening & tension does not remain constant
- work is not being done

Question 22

concentric

Answer 22

muscle shortens, type of isotonic contraction

Question 23

eccentric

Answer 23

muscle lengthens, isotonic contraction

Question 24

sphincters

Answer 24

rings of skeletal muscle - anchor to themselves

Question 25

concentric vs eccentric on load & velocity

Answer 25

C- larger load = slower velocity
E- larger load = faster velocity

Question 26

level systems mechanims

Answer 26

interactive units - spring like mechanism - has faster efficiency bc energy transfer is quicker

Question 27

3 ways ATP can be produced for muscle use & what one is the slowest

Answer 27

creatine phosphate
anaerobic pathway (glycolysis)
aerobic pathway (TCA cycle) - slowest

Question 28

ratio of creatine phosphate to ATP

Answer 28

5:1

5 creatine phosphate, 1 ATP

Question 29

slow oxidative fibers

Answer 29

high resistance to fatigue

Question 30

fast oxidative fibers

Answer 30

intermediate resistance to fatigue

Question 31

fast glycolytic fibers

Answer 31

low resistance to fatigue

Question 32

T or F: muscle fatigue causes drop in ATP & increase in ADP

Answer 32

T

Question 33

T or F: extracellular K accumulates during muscle fatigue due to reduction in membrane potential

Answer 33

T

Question 34

T or F: smooth muscle is 10% of body weight

Answer 34

T

Question 35

T or F: smooth muscle lacks tropomyosin & troponin

Answer 35

T

Question 36

smooth muscle- passive vs gradual depolarization

Answer 36

passive- depolarization at threshold of initial AP

gradual- triggers AP & responds to changes in Na rates

Question 37

T or F: different neurotransmitters can be used as inputs for same place

Answer 37

T

Question 38

phasic vs tonic

Answer 38

phasic- smooth muscle contracts in bursts

tonic- smooth muscle is partially contracted at all times

Question 39

phosphagen- what is it, location & example

Answer 39

energy storing compound, found in muscle & nervous tissue

example) creatine kinase