Skeletal Muscles Flashcards

1
Q

which muscles can regenerate?

A

smooth (uterus)

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2
Q

which muscles cannot regenerate easily?

A

skeletal

cardiac

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3
Q

what do the intercalated discs represent?

A

where one cardiac cell joins with another

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4
Q

which type of muscle is most prominent?

A

smooth muscle

skin, uterogenital, etc, etc

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5
Q

endomysium

A

wrapping that surrounds a single muscle fiber

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6
Q

perimysium

A

wrapping that surrounds a fascicle (bundle of single muscle fibers)

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7
Q

epimysium

A

wrapping that surrounds an entire muscle

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8
Q

thick filament

A

myosin

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9
Q

thin filament

A

actin (globular actin)
tropomyosin
troponin

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10
Q

dark band

A

A- band
(anisotropic)
-thick and thin filament

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11
Q

light band

A

I-band
(isotropic)
-only thin filament

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12
Q

which type of fiber moves during muscle contraction?

A

thin filament

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13
Q

why is the z-line so important?

A

distance between z to z gets shorter when contraction takes place

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14
Q

sarcomere

A

from z-to-z

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15
Q

titin

A

muscle protein that is attached to the thick filament in the sarcomere (helps recoil)

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16
Q

what does the H zone contain?

A

only myosin (no thin filament)

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17
Q

which band disappears when muscle contracts

A

I-band

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18
Q

where is Ca stored in the skeletal muscle fiber?

A

sarcoplasmic reticulum

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19
Q

sarcoplasmic reticulum

A

modified smooth ER inside muscle cells

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20
Q

sarcolema

A

plasma membrane of muscle cell

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21
Q

transverse tubules (t-tubules)

A

go into the muscle cells from outside to in

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22
Q

what are the three subunits of troponin?

A
troponin C (binds to calcium)
troponin T (binds to tropomyosin)
troponin I
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23
Q

what kind of tissue is epimysium?

A

dense irregular CT

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24
Q

what kind of tissue is perimysium?

A

dense irregular CT

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25
what kind of tissue is endomysium?
loose areolar
26
fascia
supports and surrounds entire organs and muscles
27
superficial fascia
separates muscle from skin | loose areolar CT
28
deep fascia
holds muscles with similar functions together | dense irregular CT
29
compartment syndrome
muscle swells, but fascia does not give, which occludes blood supply because of pressure on tissues - treatment is fasciotomy - swelling peaks 48-72 hours after trauma
30
aponeurosis
broad, sheath-like tendon
31
what does the m-line contain?
thick filament with protein
32
what are the structural proteins in muscle?
``` actin, myopsin, dystrophin, attaches to myofibrils and the other end is attached to plasma membrane (anchors myofibrils) titin, myomesin ```
33
muscular dystrophy
duchennes-x-linked recessive -genetic defect where dystrophin is abnormal, architecture of the muscle is out of wack and muscle fibers degrade and normal muscles turn into adipose tissue
34
myoglobin
cell that carries oxygen to the muscles (supposed to be inside the cell)
35
who is the primary intracellular cation?
potassium (K+)
36
rabdomyolosis
breakdown of muscle fibers that leads to myoglobin in blood which is toxic to kidneys and can cause kidney damage - trauma - overexcersion
37
sudden surge of potassium from muscle cells can cause
stopping of heart | renal failure
38
glycogen
storage form for glucose | -stored in skeletal muscle and liver
39
which type of filament is more prominent in muscle?
thin filament
40
what type of design does thin filament make around thick filament?
hexagonal
41
concentric
contraction with shortening
42
isometric
contraction without shortening
43
eccentric
contraction with lengthening
44
how do the ends of muscles move?
one end stays stationary while the other end shortens
45
what are the two binding sites on myosin?
1. thin filament | 2. ATP
46
what happens during the resting state?
concentration of cytoplasmic calcium is low (stored in sarcoplasmic reticulum) myosin are in an energized state
47
allosteric modification
adjacent binding sites modify the affinity of binding in other sites (when ATP binds to myosin head, it decreases affinity to bind to tropomyosin site)
48
excitation-contraction coupling
sarcolemma of the muscle fibers leads to cross-bridge formation and contraction
49
what type of leakage channels does sarcolemma have?
Na+ (goes out) and K+(has more of these) (goes in)
50
what established gradient of Na and K
sodium potassium pump
51
what is the resting membrane potential?
-70mV
52
action potential completes before what?
contraction
53
what is the threshold?
-55mV
54
what is the maximum gradient of an AP?
+30mV
55
what is the triad?
t-tubule is connected to sarc. reticulum on either side
56
what is the foot protein involved in calcium release?
ryanodine receptor (forms a calcium channel)
57
what is responsible for returning calcium to the SR?
calcium-ATPases
58
motor end plate
area that is modified in the skeletal muscle that has the receptor for the nerve transmitters -contains envagination called junction folds
59
motor neuron terminal
contains acetylcoline
60
motor unit
single motor neuron and all the muscle fibers it innervates
61
somatic motor (efferent) neurons
cell bodies in brain and ventral gray matter of spinal cord largest diameter axons in body myelinated
62
nicotinic receptors
cholinergic receptors at the motor end plate
63
cholinergic receptors come in two types
nicotinic receptors | muscurinic receptors
64
what ions are allowed to flow when an acetylcholine comes through the motor end plate?
Na and K
65
what clears out acetylcholine?
acetylcholinesterase
66
acetylcholinesterase inhibitors
used for Alzheimers medicines | -may slow illness slightly, but does not do much else
67
IPSP
inhibitory post synaptic potential
68
what types of ion channels are present in sarcolemma and along axons of neurons
individual voltage gated sodium and potassium channels
69
curare
binds to nicotinic receptor but does not open Na channels - is not degraded - muscle paralysis including respiratory muscles
70
gallamine
similar to curare | used to induce muscle paralysis during surgery when the airway is controlled
71
organophosphates
insecticides and nerve cases inhibits acetylcholinesterase -maintain depolarization -receptors become insensitive
72
botox
prevents vesicular fusion needed to acetylcholine release from motor neuron synaptic end bulb