muscular physiology

Question 1

are somatic motor neurons voluntary

Answer 1

yes

Question 2

what is one motor unit

Answer 2

one motor neuron

all muscle fibers connected to it

Question 3

how many neurons can be on one muscle fiber

Answer 3

one

Question 4

do muscle fibers of one motor unit contract in unison or separately

Answer 4

in unison

Question 5

where is where a nerve fiber and muscle fiber meet

Answer 5

synapse

Question 6

where is the gap between the axon terminal and sarcolemma

Answer 6

synaptic cleft

Question 7

how is the sarcolemma modified to allow for more Ach receptors

Answer 7

folds

Question 8

what “eats” Ach and makes movements not carry on

Answer 8

acetylcholasterase

Question 9

what is the swollen end of a nerve fiber

Answer 9

axonal terminal

Question 10

what happens right after the arrival of a nerve signal

Answer 10

Ach releases from vesicles

Question 11

what happens after ACh releases from synaptic vesicles and it binds to the receptor

Answer 11

depolarization of the membrane

Question 12

at rest, what part of the membrane is + / -

Answer 12

+: extracellular

-: intracellular

Question 13

what is the difference in electric potential between the inside and outside of a cell called

Answer 13

membrane potential / membrane voltage

Question 14

what 3 ions are in excess on the outside of a cell during membrane potential

Answer 14

sodium
calcium
chlorine

Question 15

what ion is in excess on the inside of a cell during membrane potential

Answer 15

potassium

Question 16

what is the increase of positivity of membrane potential

Answer 16

depolarization

Question 17

what ion is constantly leaking out of the membrane

Answer 17

potassium

Question 18

what determines the negative resting potential of the membrane

Answer 18

potassium leaking out of the cell and negative proteins within the cell

Question 19

what causes sodium channels to open

Answer 19

ACh binding to receptors

Question 20

sodium channels opening cause a the cell membrane to be ________

Answer 20

depolarized

Question 21

what is the cause of repolarization of the cell

what closes and what enters

Answer 21

sodium channels close and potassium channels open and K goes back into the cell

Question 22

what is the time after a muscle fiber has been stimulated to pass before the muscle can be stimulated to contract again

Answer 22

hyperpolarization

Question 23

what refers to the increase in negativity of membrane AGAIN

Answer 23

hyper polarization

Question 24

what is excitation contraction coupling

Answer 24

the fact that a contraction FOLLOWS an action potential

Question 25

where does an action potential propagate down to reach the deep part of a muscle fiber

Answer 25

T tubules

Question 26

what is calcium's job in muscle contraction

Answer 26

to bind to troponin so that tropomyosin will roll off of actin

Question 27

what is occurring during a recovery stroke _____ of the head

Answer 27

hydrolysis of ATP to ADP and Pi cocking

Question 28

during a power stroke, what is happening

Answer 28

myosin is sliding over the actin

Question 29

what breaks the cross bridge between actin and myosin

Answer 29

ATP binds to myosin

Question 30

what causes the shortening of muscles

Answer 30

sarcomeres shortening

Question 31

what are pulled closer together during a muscle contraction

Answer 31

Z discs

Question 32

where does calcium travel

Answer 32

Down t tubules

Question 33

how does a muscle stop itself from contracting once its fatigued or has run out of ATP (2)

Answer 33

acetylcholinesterase reabsorption of Ca by the sarcoplasmic reticulum

Question 34

what refers to the fact that the amount of tension generated by a muscle depends of how shortened it was before it was stimulated

Answer 34

length tension relationship

Question 35

what is the optimum resting length what does it maintain

Answer 35

2-2.5 um muscle tone

Question 36

why is a muscle contraction weak if the muscle is too relaxed

Answer 36

there is minimal overlap between myosin and actin

Question 37

why is there a weak contraction when a muscle is overly shortened

Answer 37

myosin will bump into z discs and won't be able to contract any farther

Question 38

what is a quick cycle of contraction and relaxation when stimulus is at or above the threshold

Answer 38

a twitch

Question 39

what is the graph that illustrates the amount of tension of a muscle over time

Answer 39

a myogram

Question 40

what are the 3 phases of a twitch

Answer 40

latent contration relaxation

Question 41

what period the delay between stimulus and contraction called why is this required this generates ______ tension

Answer 41

latent period time required for excitation and tensing of elastic components of muscle internal

Question 42

the contraction phase generates ______ tension

Answer 42

external

Question 43

what is the force generated to overcome a load and produce movement

Answer 43

external tension

Question 44

when is the phase where tension declines to the baseline how much time does this take relatively what is absorbed to stop muscle contraction

Answer 44

relaxation phase longer than contraction Ca

Question 45

_____ muscles work more quickly during exercise ______ influences cross bridges

Answer 45

warm hydration

Question 46

what is the process of bringing more motor units into play with stronger stimuli

Answer 46

recruitment of multiple motor units

Question 47

what is the principle that states that weak stimuli recruit small units while strong units recruit large units for powerful movements

Answer 47

size principle

Question 48

what is the theory that states that after a certain threshold, muscles will contract with the same force

Answer 48

all or nothing theory

Question 49

muscle twitches have _____ peaks

Answer 49

identical

Question 50

during imcomplete tetanus / temporal summation, what happens is this normal what causes this to happen what is the "incomplete" referencing

Answer 50

each new twitch rides on the previous one and produces a stronger muscle contraction yes more release of Ca incomplete relaxation between stimuli

Question 51

during complete/ fused tetanus, what happens is this normal

Answer 51

steady contractions no

Question 52

what is isometric muscle contraction

Answer 52

holding tension (internal tension but external resistance)

Question 53

what is isotonic contraction

Answer 53

muscle changes length but not tension

Question 54

what is a contraction where the muscle shortens

Answer 54

concentric contraction

Question 55

what is a contraction where the muscle lengthens

Answer 55

eccentric contraction

Question 56

when is calcium released from the SR to bind to troponin

Answer 56

after an action potential has propagated down the length of the muscle