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A & P > Chapter 10,11,12 Continue > Flashcards

Chapter 10,11,12 Continue Flashcards

1
Q

The process in which nerve action potentials lead to muscle action potentials

A

Excitation

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2
Q

Events that link the action potentials on the sarcolemma to activation of the myofilaments, thereby preparing them to contract

A

Excitation- contraction coupling

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3
Q

step in which the muscle fiber develops tension and may shorten

A

Contraction

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4
Q

When its work is done, a muscle fiber relaxes and returns to its resting length

A

relaxation

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5
Q

Arrival of nerve signal

opens voltage- gated calcium channels

A

step 1

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6
Q

Acetylcholine (ACh) release

Calcium enters the cell thru gates, opened by voltage

A

Step 2

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7
Q

Binding of ACh to receptor

two ACh molecules bind to each receptor protein, opening Na and K channels

A

Step 3

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8
Q

Opening of ligand- regulated ion gates; creation of end- plate potential
Na enters; shifting RMP goes from -90 mV to + 75 mV then K exits (Action Potential) and RMP returns to -90 mV; quick voltage shift end of plate potential

A

Step 4

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9
Q

Quick voltage shift

A

end- plate potential (EPP)

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10
Q

Opening of voltage- regulated ion gates; creation of action potentials
Voltage change (EPP) in end- plate region opens nearby voltage- gated channels producing an action potential that spreads over muscle surface
Causing Action Potential after Action Potential

A

Step 5

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11
Q

Action potentials propagated down T tubules

A

Step 6

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12
Q

Calcium released from terminal cisternae

Ca gets diffused thru the muscles

A

Step 7

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13
Q

Binding of calcium to troponin in thin filaments

A

Step 8

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14
Q

Shifting of tropomyosin; exposure of active sites on actin

Troponin- tropomyosin complex changes shape and exposes active sites on actin

A

Step 9

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15
Q

Hydrolysis of ATP to ADP + P; activation and cocking of myosin head
“Pull hammer on gun back” on myosin which is pulled back by ATP

A

Step 10

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16
Q

Fermat ion of myosin -actin cross- bridge

Myosin comes back and attaches to Actin

A

Step 11

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17
Q

head binds to actin active site forming a

A

myosin- actin cross- bridge

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18
Q

Binding of new ATP; breaking of cross- bridge

A

Step 13

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19
Q

Power stroke sliding of thin filament over thick filament

Myosin fires= ATP molecules

A

Step 12

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20
Q

Cessation of nervous stimulation and ACh release

Relaxation; stop stimulation

A

Step 14

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21
Q

ACh breakdown by acetylcholinesterase (AChE)

A

Step 15

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22
Q

Reabsorption of Calcium ions by sarcoplasmic reticulum

A

Step 16

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23
Q

Loss of calcium ion from troponin

Give myosin one final ATP

A

Step 17

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24
Q

Return of tropomyosin to position blocking active sites of actin

A

Step 18

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25
Q

the amount of tension generated by a muscle and the force of contraction depends on how stretched or contracted it was before it was stimulated

A

Length- tension relationship

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26
Q

a weak contraction results in thick filaments too clos to Z discs and cannot slide

A

Overly contracted

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27
Q

a weak contraction results little overlap of thin and thick does not allow for very many cross- bridges to form

A

Too stretched

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28
Q

produces greatest force when muscle contracts

A

Optimum resting length

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29
Q

central nervous system continually monitors and adjusts the length of the resting muscle , and maintains a state of partial contraction

A

muscle tone

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30
Q

cause sarcoplasmic reticulum to break down quickly and release calcium molecules begin to break down
hardening of muscle and stiffening of body beginning 3-4 hours after death

A

Rigor mortis

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31
Q

a chart of the timing and strength of muscle’s contraction

A

Myogram

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32
Q

the response of a muscle to weak electrical stimulus seen in a frog gastrocnemius

A

Sciatic nerve preparation

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33
Q

what does a weak electrical stimulus do

A

causes no contraction

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34
Q

minimum voltage necessary to generate an action potential in the muscle fiber and produce a contraction

A

threshold

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35
Q

a quick cycle of contraction when stimulus is at threshold or higher
1-18 steps (1 time )

A

twitch

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36
Q

2 ms delay between the onset of stimulus and the onset of twitch response ; internal tension
time required for excitation- contracting coupling, and tension of elastic components of the muscle
everything before contraction

A

Latent period

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37
Q

force generated during latent period and no shortening of the muscle occurs
getting slack out

A

Internal tension

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38
Q

phase in which filaments slide and the muscle shortens
once elastic components are taut, muscle begins to produce external tension in muscle that moves a load
short- lived phase

A

Contraction phase

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39
Q

parts of body are moving

once elastic components are taut, muscle begin to

A

external tension

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40
Q

SR quickly reabsorbs Ca myosin releases the thin filaments, and tension declines
muscle returns to resting length
entire twitch lasts from 7- 100 ms

A

Relaxation phase

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41
Q

no contraction at all

didn’t get up to -55 mV

A

sub threshold stimulus

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42
Q

a twitch is produced

twitches caused by increased voltage are no stronger than those at threshold

A

threshold intensity and above

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43
Q

Do muscle fibers act the same to every spike no matter if its -55 or over ?

A

Yes

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44
Q

stimuli arriving closer together produce stronger twitches

A

stimulus frequency

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45
Q

in sarcoplasm can vary the frequency

A

concentration of Ca

46
Q 
Stimulus frequency 
Concentration of Ca 
stretch 
temperature 
PH 
State of hydration 
all influence what
A

how much force our muscles have

47
Q

how much ___ muscle was before it was stimulated

A

stretched

48
Q

___ of the muscles - warmed- up muscle contracts more strongly; enzymes work more quickly

A

Temperature

49
Q

Lower than normal __ of sarcoplasm weakens contraction- __

A

pH; fatigue

50
Q

___ of muscle affects overlap pH thick and thin filaments

A

State of Hydration

51
Q

Stimulating the nerve and higher and higher voltages produces
use more muscle with stronger voltage

A

stronger contraction

52
Q

the process of bringing more motor units into play

A

Recruitment or multiple motor unit (MMU)

53
Q

each stimulus produces identical twitches and full recovery between twitches
up to 10 stimuli per second

A

Twitch

54
Q

10-20 stimuli per second (staircase)
stimulus recovers fully between twitches but each twitch develops more tension than the one before
contraction get stronger and stronger and sarcoplasmic reticulum doesn’t have enough time to reabsorb Ca

A

Treppe

55
Q

20 -40 stimulus per second
ca cant be reabsorbed fast enough and myosin and actin don’t have enough time to relax
each new stimulus arrives before the previous twitch is over
higher tension

A

Incomplete tetanus

56
Q

muscle relaxes only partially between stimuli

produces a state of sustained fluttering contraction

A

Incomplete tetanus

57
Q

40 -50 stimuli per second tasd muscle lock up
muscle had no time to relax between stimuli
rapid then flat lines

A

Complete tetanus

58
Q

muscle is producing internal tension while an external resistance causes it to stay the same length or become longer

A

isometric muscle contraction

59
Q

muscle changes in the with no change in tension
concentric contraction
eccentric contraction

A

Isotonic muscle contraction

60
Q

muscle shortens as it maintains tension

A

Concentric contraction

61
Q

muscle lengthens as it maintains tension

A

eccentric contraction

62
Q

All muscles depend on what

A

ATP

63
Q

___ supply depends on availability of : oxygen and organic energy sources such as glucose and fatty acids

A

ATP

64
Q

__ is where production of ATP occurs

A

Mitochondria

65
Q

Two main pathways of ____ synthesis

Anaerobic fermentation and Aerobic respiration

A

ATP

66
Q

without oxygen
Enables cells to produce ATP in the absence of oxygen
yields little ATP and toxic lactic acid, major factor in muscle fatigue
ex. when running, hold breath

A

Anaerobic fermentation

67
Q

With oxygen
produces far more ATP
Less toxic and produces
requires a continual supply of oxygen

A

Aerobic respiration

68
Q

Oxygen need is briefly supplied by myoglobin for limited amount of aerobic respiration at onset- rapidly depleted
Muscle meet moser of ATP demand by borrowing phosphate groups from other molecules and transferring them to ADP

A

Short intense exercise (100m dash)

69
Q

Two enzyme systems control these phosphate transfers

A

Myokinase

Creatine kinase

70
Q

Transfer P from one ADP to another converting the latter to ATP

A

Myokinase

71
Q

Obtain P from phosphate storage molecule creatine phosphate (CP)
Fast acting system that helps maintain the ATP level while other ATP generating mechanisms are being activated

A

Creatine kinase

72
Q

ATP and CP collectively
Provides nearly all energy used for short bursts of intense activity
1 min, 6 seconds of sprinting or fast swimming, important in activities requiring brief but max effort
Ex football baseball weightlifting

A

Phosphagen system

73
Q

As the phosphagen system is exhausted muscles shift to what

A

Anaerobic fermentation

74
Q

Not getting oxygen to the tissue
Muscle obtain glucose from blood and their own stores glycogen
I absence of oxygen glycolysis can generate a net gain of 2 ATP for every glucose molecule consumed
Converts glucose to Latin acid

A

Anerobic fermentation

Short term energy

75
Q

The pathway from glycogen to lactic acid

A

Glycogen lactic acid system

76
Q

Anerobic fermentation produces enough ATP for how many seconds of max activity
Short term energy

A

30 to 40 seconds

77
Q

To split sugar to make ATP

A

Glycolysis

78
Q

After 49 seconds so the respiratory and cardiovascular systems catch up and deliver oxygen to the muscles fast enough for aerobic respiration to meet most of the ATP demands

A

Long term energy

79
Q

Aerobic respiration produce 36 ATP per glucose
Efficient means of meeting the ATP demand sod prolonged exercise
Ones rate of oxygen consumption rises from 3 to 4 minutes and levels off to a steady state in which aerobic ATP production keeps pace with demand
Little lactic acid accumulates under steady state condition

A

Long term energy

80
Q

Progressive weakness and loss of contractility from prolonged use of the muscles
Repeated squeezing of rubber ball
Holding textbook out level to the floor

A

Muscle fatigue

81
Q

ATP synthesis declines as glycogen is consumed
ATP shortage slows down the Na K pumps compromises their ability to maintain the resting membrane potential and excitability of the muscle fibers
Lactic acid lowers pH sacroplasm
Inhibited enzymes involved in contraction ATP synthesis and other aspects of muscle function
More acidic less likely to contract will fatigue

A

Fatigue is thought to result from

82
Q

Aerobic activity the ability to maintain high intensity exercise for more than 4 to 5 mins
Determined in large part by ones maximum oxygen uptake (VO2 max)

A

Endurance

83
Q

Taking oral creatine increase level of creatine phosphate in muscle tissue and increases speed of ATP regeneration
Carbohydrate loading

A

Beating fatigue

84
Q

Dietary regimen
Packs extra glycogen into muscle cells
Extra glycogen is hydrophilic and add 2.7 g water per gram of glycogen
Athletes feel sense of heaviness

A

Carbohydrate loading

85
Q

Abundane mitchondria, myoglobin , capillaries deep red color
Adapted aerobic respiration and fatigue resistance
Relative long twitch lasting about 100 ms
Soules of calf and postural muscles of the back
Walking
Aerobic

A

Slow oxidative( SO) slow twitch red type T fibers

86
Q

Fibers are well adapted for quick responses but not for fatigue resistance
Rich in enzymes of phosphagen and glycogen lactic acid systems generate lactic acid causing fatigue
Poor in mitchondria myoglobin and blood capillaries which gives pale appearance
Extrinsic eye muscles gastrocnemius and biceps brachi
Anaerobic respiration

A

Fast glycolysis (FG) fast twitch white type 2 fibers

87
Q

Ratio of different fiber types have genetic predisposition

Muscles are a combination of both but may be more of one than the other

A

Born sprinter

88
Q

Exists because of unequal electrolyte distribution between extracellular fluid and intercellular fluid
Results from combined effect of three factors
Ions diffuse down their concentration gradient through the membrane
Plasma membrane is selectively permeable and allows some ions to pass easier than others
Electrical attraction of cations and anions to each other

A

Resting membrane potential

89
Q

Have the greatest influence of RMP
Plasma membrane is more permeable to K than any other ion
Leaks out until electrical charge of cytoplasmic anions attracts it back in and equilibriumvia reached and net diffusion of K stops
k is about 49 times as concentrated in the ICF as in the ECF

A

Potassium ion

90
Q

Cannot escape due to size or charge( phosphates , sulfate a, small organic acids, proteins, ATP, and RNA )

A

Cytoplasmic anions

91
Q

Point where a nerve fiber meets its target cell (intervates)

A

Synapse

92
Q

When target cell is a muscle fiber (neuron and muscle cell)
Each terminal branch of the nerve fiber within the NMJ forms separate synapse with the muscle fiber
One nerve fiber stimulates the muscle fiber at several points within the NMJ

A

Neuromuscular junction (NMJ)

93
Q

Swollen end of nerve fiber
Contains synaptic vesicles filled with acetylcholine (ACh)
Connects to muscle cell nuerotransmitter

A

Synaptic knob

94
Q

Tiny gap between synaptic knob and muscle sacrolemma

A

Synaptic cleft

95
Q

Envelopes and isolates all of the NMJ from surronding tissue fluids (insulation protect NMJ)

A

Schwann cell

96
Q

Undergo Exocytosis releasing ACh into synaptic cleft

A

Synaptic vesicles

97
Q

__ proteins incorporated into muscle cell plasma membrane

Junction folds

A

50 million ACh receptors

98
Q

Of sacrolemma beneath synaptic knob
Increase surface area holding ACh receptors
Lack of receptors leads to paralysis in disease myasthenia graves

A

Junctional folds

99
Q

Thin layer of collagen and Glycoprotein separates Schwann cell and entire muscle cell from surrounding tissues
Contains acetylcholinesterase (AChE) that breaks down ACh after contraction causing relaxation
Connective tissue layer that surrounds everything

A

Basal lamina

100
Q

Slightly more K leaves the cell than Na entering

Drops the membrane voltage 1 or 2 mV more neg than the original RMP neg overshoot hyper polarization or after potential

A

K gates stay open longer than N gates

101
Q

_ and _ switch places across the membrane during an action potential

A

Na and K

102
Q

___ layers of the cytoplasm next to the cell membrane is affected
In reality very few ions are involved

A

Only a thin layer

103
Q

Action potential is called __ because it happens fast

A

Spike

104
Q

Out of 3 Na for every 2 K it brings in
Works continuously to compensate for Na and K leakage and requires great deal of ATP
70% of the energy requirement of the nervous system
Necessitates glucose and oxygen be supplied to nerve tissue
Pump contributes about -3 mV to the cells resting membrane potential of -70 mV

A

Na k pumps

105
Q

__ concentrated outside of cell

A

Na

106
Q

_ concentrated inside cell

A

K

107
Q

__ is a rapid up and down shift in the membrane voltage
Depolarize the membrane
Threshold

A

Action potential

108
Q

Critical voltage to which local potentials must rise to open the voltage regulated gates
-55 mV

A

Threshold

109
Q

When threshold is reached neuron __ and produces and action potential

A

Fires

110
Q

More and more Na channels open in the trigger zone in a positive feedback cycle creating a rapid rise in membrane voltage called

A

Spike

111
Q

When rising membrane potential passes _ mV Na gates are inactivated
Begin closing when all closed the voltage peaks at + 35 mV
Membrane now positive on the inside and beg on the outside
Polarity reversed from RMP depolarization

A

0 mV

112
Q

By the time the voltage gates peaks the slow ___ are fully open
K repelled by the positive intercellular fluid now exit the cell
Their outflow repolarizes the membrane shifts the voltage back to neg numbers retiring toward RMP

A

Slow K gates

A & P (4 decks)

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