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Muscle test Flashcards

(64 cards)

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1
Q

Skeletal muscle tissue

A

Attached to bones and skin
Striated
Voluntary (i.e., conscious control)
Powerful

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2
Q

Cardiac muscle tissue

A

Only in the heart
Striated
Involuntary

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3
Q

Smooth muscle tissue

A

In the walls of hollow organs
Not striated
Involuntary

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4
Q

functions of muscle

A

Movement of bones or fluids
Maintaining posture and body position
Stabilizing joints
Heat generation

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5
Q

skeletal muscle characteristics

A

Excitability
Contractility
Extensibility
Elasticity

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6
Q

excitability

A

responsiveness or irritability: ability to receive and respond to stimuli

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7
Q

Contractility

A

ability to shorten when stimulated

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8
Q

Extensibility

A

ability to be stretched

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9
Q

Elasticity

A

ability to recoil to resting length

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10
Q

Epimysium

A

dense regular connective tissue surrounding entire muscle

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11
Q

Perimysium

A

fibrous connective tissue surrounding fascicles (groups of muscle fibers)

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12
Q

Endomysium

A

fine areolar connective tissue surrounding each muscle fiber

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13
Q

muscle flow chart

A

muscle is covered by epimysium
muscle is made up of fasicles covered by perimysium
fasicles are made of muscle fibers (muscle cells) covered by endomysium
muscle fibers made of myofibrils which are made up of filaments (actin and myosin)

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14
Q

muscles attach directly

A

epimysium of muscle is fused to the periosteum of bone or perichondrium of cartilage

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15
Q

muscles attach indirectly

A

connective tissue wrappings extend beyond the muscle as a ropelike tendon or sheetlike aponeurosis

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16
Q

skeletal muscle cells

A

Cylindrical cell up to 30 cm long
Multiple peripheral nuclei
Many mitochondria
myofibrils, sarcoplasmic reticulum, and T tubules
densely packed rodlike elements (80 percent of cell volume)
striations

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17
Q

glycosomes for

A

glycogen storage

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18
Q

myoglobin for

A

oxygen storage

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19
Q

striations in muscle cells

A

perfectly aligned repeating series of dark A bands and light I bands

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20
Q

Sarcomere

A

Smallest contractile unit (functional unit) of a muscle fiber
The region of a myofibril between two successive Z discs
Composed of thick and thin myofilaments (actin myosin)

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21
Q

thick filaments (myosin)

A

run the entire length of an A band

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22
Q

thin filaments (actin)

A

run the length of the I band and partway into the A band

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23
Q

Z disc/line

A

coin-shaped sheet of proteins that anchors the actin and connects myofibrils to one another

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24
Q

H zone

A

lighter midregion where filaments do not overlap

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25
m line
line of protein myomesin that holds adjacent thick filaments together
26
protein myosin tails contain
2 interwoven, heavy polypeptide chains
27
protein myosin heads contain
2 smaller, light polypeptide chains that act as cross bridges during contraction Have binding sites for actin of thin filaments Also have binding sites for ATP Has ATPase enzymes
28
Actin contains
Twisted double strand of fibrous protein F actin | Tropomyosin and troponin
29
F actin consists of
of G (globular) actin subunits
30
G actin consists of
active sites for myosin head attachment during contraction
31
tropomyosin
block binding site for myosin
32
troponin
changes shape when calcium binds to it which moves tropomyosin out of the way
33
thick filament
myosin molecules whose heads protrude at opposite ends
34
thin filament
two strands of actin subunits twisted into a helix plus troponin and tropomyosin
35
Sarcoplasmic Reticulum
network of smooth endoplasmic reticulum surrounding each myofibril Pairs of terminal cisternae form perpendicular cross channels Functions in the regulation of intracellular Ca2+ levels
36
T-tubules
Continuous with the sarcolemma Penetrate the cell’s interior at each A band–I band junction part of triads conduct impulses deep into muscle fiber
37
triad
terminal of cisternae of SR, t tubule, terminal of cisternae of SR
38
t tubule proteins
voltage sensors
39
SR foot proteins
gated channels that regulate calcium release from the SR cisternae
40
why does generation of force does not necessarily cause shortening of the fiber
when the load is greater than the muscle can move, the muscle doesnt shorten ex trying to pick up a car
41
Shortening occurs when
tension generated by cross bridges on the thin filaments exceeds forces opposing shortening
42
muscle contraction steps with actin and myosin: relaxed state
In the relaxed state, thin and thick filaments overlap only slightly
43
muscle contraction steps with actin and myosin: during contraction
myosin heads bind to actin, detach, and bind again, to propel the thin filaments toward the M line
44
As H zones shorten and disappear
sarcomeres shorten, muscle cells shorten, and the whole muscle shortens
45
steps to contraction
activation and excitation
46
activation
neural stimulation at a neuromuscular
47
Excitation-contraction coupling
Generation and propagation of an action potential along the sarcolemma Final trigger: a brief rise in intracellular Ca2+ levels
48
skeletal muscle stimulation travel path
Skeletal muscles are stimulated by somatic motor neurons Axons of motor neurons travel from the central nervous system via nerves to skeletal muscles Each axon forms several branches as it enters a muscle Each axon ending forms a neuromuscular junction with a single muscle fiber
49
neural muscular junction
Situated midway along the length of a muscle fiber contain synaptic cleft Synaptic vesicles of axon terminal contain the neurotransmitter acetylcholine (ACh) Junctional folds of the sarcolemma contain ACh receptors
50
how neural muscular junction works
Nerve impulse arrives at axon terminal ACh is released and binds with receptors on the sarcolemma Electrical events lead to the generation of an action potential which travels down t tubule to cause SR to dump calcium which causes troponin to shift and unblock tropomyosin
51
ach affects are terminated by
achesterase
52
What does achesterase do
which prevents continued muscle fiber contraction in the absence of stimulation
53
steps after ach binds to receptor on sarcolemma when crossing synaptic cleft
local depolarization (end plate potential) generation and propagation of action potential repolarization
54
local depolarization (end plate potential)
ACh binding opens chemically (ligand) gated ion channels Simultaneous diffusion of Na+ (inward) and K+ (outward) More Na+ diffuses, so the interior of the sarcolemma becomes less negative and loses polarity
55
Generation of an action potential
End plate potential spreads to adjacent membrane areas Voltage-gated Na+ channels open Na+ influx decreases the membrane voltage toward a critical threshold If threshold is reached, an action potential is generated
56
propagation of an action potential
Local depolarization wave continues to spread, changing the permeability of the sarcolemma Voltage-regulated Na+ channels open in the adjacent patch, causing it to depolarize to threshold
57
repolarization of an action potential
Na+ channels close and voltage-gated K+ channels open K+ efflux rapidly restores the resting polarity Fiber cannot be stimulated and is in a refractory period until repolarization is complete Ionic conditions of the resting state are restored by the Na+-K+ pump
58
What maintains polarity
3 clacium going out and 2 potassium going in leads to repolarization
59
latent period
Time when E-C coupling events occur | Time between AP initiation and the beginning of contraction
60
stopping contraction At low intracellular Ca2+ concentration
Tropomyosin blocks the active sites on actin Myosin heads cannot attach to actin Muscle fiber relaxes
61
stopping contraction At higher intracellular Ca2+ concentrations
Ca2+ binds to troponin Troponin changes shape and moves tropomyosin away from active sites Events of the cross bridge cycle occur When nervous stimulation ceases, Ca2+ is pumped back into the SR and contraction ends Continues as long as the Ca2+ signal and adequate ATP are present
62
cross bridge cycle
Cross bridge formation—high-energy myosin head attaches to thin filament Working (power) stroke—myosin head pivots and pulls thin filament toward M line Cross bridge detachment—ATP attaches to myosin head and the cross bridge detaches “Cocking” of the myosin head—energy from hydrolysis of ATP cocks the myosin head into the high-energy state (pull back to gain another actin)
63
what makes myosin heads let go and cock
atp makes it let go, hydrolysis makes it cock
64
why rigamortes people are stiff
stiff dead person, no ATP made so cross bridges are stuck. When pumps stop, calcium leaks and causes myosin heads to grab, get stiff, but ATP is gone so cant move

Anatomy (29 decks)

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