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anatomy exam 2 > muscular physiology > Flashcards

muscular physiology Flashcards

1
Q

are somatic motor neurons voluntary

A

yes

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2
Q

what is one motor unit

A

one motor neuron

all muscle fibers connected to it

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3
Q

how many neurons can be on one muscle fiber

A

one

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4
Q

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

A

in unison

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5
Q

where is where a nerve fiber and muscle fiber meet

A

synapse

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6
Q

where is the gap between the axon terminal and sarcolemma

A

synaptic cleft

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7
Q

how is the sarcolemma modified to allow for more Ach receptors

A

folds

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8
Q

what “eats” Ach and makes movements not carry on

A

acetylcholasterase

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9
Q

what is the swollen end of a nerve fiber

A

axonal terminal

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10
Q

what happens right after the arrival of a nerve signal

A

Ach releases from vesicles

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11
Q

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

A

depolarization of the membrane

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12
Q

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

A

+: extracellular

-: intracellular

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13
Q

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

A

membrane potential / membrane voltage

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14
Q

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

A

sodium
calcium
chlorine

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15
Q

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

A

potassium

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16
Q

what is the increase of positivity of membrane potential

A

depolarization

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17
Q

what ion is constantly leaking out of the membrane

A

potassium

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18
Q

what determines the negative resting potential of the membrane

A

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

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19
Q

what causes sodium channels to open

A

ACh binding to receptors

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20
Q

sodium channels opening cause a the cell membrane to be ________

A

depolarized

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21
Q

what is the cause of repolarization of the cell

what closes and what enters

A

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

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22
Q

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

A

hyperpolarization

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23
Q

what refers to the increase in negativity of membrane AGAIN

A

hyper polarization

24
Q

what is excitation contraction coupling

A

the fact that a contraction FOLLOWS an action potential

25
Q

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

A

T tubules

26
Q

what is calcium’s job in muscle contraction

A

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

27
Q

what is occurring during a recovery stroke

_____ of the head

A

hydrolysis of ATP to ADP and Pi

cocking

28
Q

during a power stroke, what is happening

A

myosin is sliding over the actin

29
Q

what breaks the cross bridge between actin and myosin

A

ATP binds to myosin

30
Q

what causes the shortening of muscles

A

sarcomeres shortening

31
Q

what are pulled closer together during a muscle contraction

A

Z discs

32
Q

where does calcium travel

A

Down t tubules

33
Q

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

A

acetylcholinesterase

reabsorption of Ca by the sarcoplasmic reticulum

34
Q

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

A

length tension relationship

35
Q

what is the optimum resting length

what does it maintain

A

2-2.5 um

muscle tone

36
Q

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

A

there is minimal overlap between myosin and actin

37
Q

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

A

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

38
Q

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

A

a twitch

39
Q

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

A

a myogram

40
Q

what are the 3 phases of a twitch

A

latent
contration
relaxation

41
Q

what period the delay between stimulus and contraction called

why is this required

this generates ______ tension

A

latent period

time required for excitation and tensing of elastic components of muscle

internal

42
Q

the contraction phase generates ______ tension

A

external

43
Q

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

A

external tension

44
Q

when is the phase where tension declines to the baseline

how much time does this take relatively

what is absorbed to stop muscle contraction

A

relaxation phase

longer than contraction

Ca

45
Q

_____ muscles work more quickly during exercise

______ influences cross bridges

A

warm

hydration

46
Q

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

A

recruitment of multiple motor units

47
Q

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

A

size principle

48
Q

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

A

all or nothing theory

49
Q

muscle twitches have _____ peaks

A

identical

50
Q

during imcomplete tetanus / temporal summation, what happens

is this normal

what causes this to happen

what is the “incomplete” referencing

A

each new twitch rides on the previous one and produces a stronger muscle contraction

yes

more release of Ca

incomplete relaxation between stimuli

51
Q

during complete/ fused tetanus, what happens

is this normal

A

steady contractions

no

52
Q

what is isometric muscle contraction

A

holding tension (internal tension but external resistance)

53
Q

what is isotonic contraction

A

muscle changes length but not tension

54
Q

what is a contraction where the muscle shortens

A

concentric contraction

55
Q

what is a contraction where the muscle lengthens

A

eccentric contraction

56
Q

when is calcium released from the SR to bind to troponin

A

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

anatomy exam 2 (6 decks)

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