Muscles Test

102 cards

ASU Summer '11 Muscle Test 


 
  
Created Jun 20, 2011
by
jackiealbert12

 

 
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1
Muscle cells capable of shortening and converting the chemical energy of ____ into ______ energy
 
ATP; mechanical
2
3 types of muscle
 
cardiac, smooth, skeletal
3
5 characteristics of muscle
 
responsiveness, conductivity, contractility, extensibility, and elasticity
4
Skeletal muscle
 
voluntary, striated, attached to bones. Myofibers as long as 30 cm. Alters light and dark transverse...
5
Fascicles
 
myofibers bundled together
6
perimysium
 
separates each fascicle from neighboring ones 
7
epimysium
 
outer edge of muscle, holds all fibers together; grade imperceptibily into connective tissue...
8
characteristics of collagen (2)
 
extensible and elastic; stretches slightly under tension and recoils when released (this protects...
9
2 types of elastic components
 
parallel components to parallel muscle cells; series components joined to ends of muscle
10
muscle fiber nuclei; fused and unfused
 
flattened inside cell membrane; fusion by multiple myoblasts during development; unfused satellite...
11
Sarcolemma
 
plasma membrane of a muscle fiber; has tunnel-like infoldings or transverse (T) tubules that...
12
sarcoplasm
 
cytoplasm; filled with myofibrils (bundle of myofilaments) and glycogen for stored energy and...
13
sarcoplasmic reticulum
 
smooth ER; network around each myofibril; dilated end-sacs (terminal cisternea) that store...
14
triad
 
T tubule and 2 terminal cisternea
15
myofilament
 
bundle of parallel protein microfilaments
16
3 types of myofilaments
 
thick, thin, elastic
17
thick filaments
 
made of 200-500 myosin molecules; 2 entwined polypeptides (golf clubs); arranged in a bundle...
18
central area
 
bare zone with no heads in thick filaments
19
thin filaments
 
two intertwined strands of fibrous (F) actin; composed of globular (G) actin with an active...
20
tropomyosin
 
held in groove of thin filaments; each block 6-7 active sites of G actin to prevent myosin...
21
troponin
 
calcium-binding molecule attached to each tropomyosin molecule
22
Elastic filaments
 
composed of springy protein called titin; anchor each thick filament to Z disc. Prevents over...
23
contractile proteins
 
myosin (thick filaments) and actin (thin filaments); do the work of shortening the muscle fiber
24
regulatory proteins
 
tropomyosin and troponin; switch that starts/stops shortening of muscle cell; contraction activated...
25
A band
 
thick filament region; lighter, central H band area contains no thin filaments
26
I band
 
thin filament region; bisected by z disc protein connectin, anchoring elastic and thin filaments
27
Muscle cells shorten because their ____ shorten
 
individual sarcomeres; (pull z discs closer together)
28
Neither thick or thin filaments change in length during shortening T/F? 
 
True
29
skeletal muscle must be stimulated by ___ or it won't contract
 
a nerve
30
cell bodies of somatic motor neurons are found _____
 
brainstem and spinal cord
31
somatic motor fibers
 
axons of somatic motor neurons; lead to skeletal muscles with each terminal branch supplying...
32
motor unit
 
each motor neuron and all the muscle fibers it innervates; dispersed throughout muscle causing...
33
postural control
 
ability to sustain long-term contraction as motor units take turns resting
34
Fine control
 
small motor units contain as few as 20 muscle fibers per nerve fiber (i.e. eye muscles)
35
strength control
 
gastrocnemius muscle has 1,000 fiber per nerve cell
36
neuromusclar junction (synapse)
 
functional connection between nerve fiber and muscle cell
37
synaptic cleft
 
tiny gap between nerve and muscle cells
38
acetycholine/ACh
 
neurotransmitter released from nerve fiber that stimulates muscle cell
39
synaptic knob
 
swollen end of nerve fiber; contains ACh in synaptic vesicles
40
junctional folds of sarcolemma
 
increase surface area for ACh receptors; contain acetycholinesterase that breaks down ACh and...
41
basal lamina
 
thin layer of collagen and glycoprotein over all of muscle fiber
42
pesticides
 
cholinesterase inhibitors; binds to acetycolinesterase and prevents it from degrading ACh;...
43
tetanus/lockjaw
 
spastic paralysis caused by toxin of Clostridium bacteria; blocks glycine release...
44
Flaccid paralysis 
 
limp muscles; due to curare that competes with ACh; respiratory arrest
45
resting membrane potential due to ___ outside of cell and ___ inside of cell
 
Na+ outside of cell; K+ (and other ions) inside the cell
46
resting membrane potential
 
difference in charge across the membrane (-90mV cell)
47
stimulation opens ion gates in membrane...
 
Na+ rushes into cell, K+ rushes out of cell
48
action potential
 
quick up-and-down voltage shift; (from negative RMP to a positive value and then back to negative)
49
4 actions involved in muscle contraction and relaxation
 
excitation, excitation-contraction coupling, contraction, relaxation
50
excitation
 
nerve action potentials lead to action potentials in muscle fiber
51
5 steps in excitation
 
nerve signal opens voltage-gated calcium channels; Calcium stimulate exocytosis of synaptic...
52
4 steps in excitation-contraction coupling
 
action potential spreading over sarcolema enters T tubules; voltage-gated channels open in...
53
4 steps in contraction
 
myosin ATPase in myosin head hydrolyzes and ATP molecule, activating the head and cocking it...
54
5 steps of relaxation
 
nerve stimulation ceases and acetylcholinesterase remove ACh from receptors; stimulation of...
55
rigor mortis
 
stiffening of the body 3-4 hours after death; deteriorating SR releases Ca; Ca activates myosin-actin...
56
length-tension relationship
 
amount of tension generated depends on length of muscle before it was stimulated 
57
overly contracted
 
weak contraction results; thick filaments too close to Z discs and can't slide
58
too stretched
 
weak contraction results; little overlap of thin and thick filaments doesn't allow for very...
59
optimum resting length
 
produces greatest force when muscles contract; CNS maintains optimal length producing muscle...
60
threshold
 
voltage producing an action potential; a single brief stimulus at that voltage produces a quick...
61
3 phases of a twitch contraction
 
latent period, contraction phase, and relaxation phase
62
latent period
 
delay; only internal tension is generated; no visible contraction occurs since only elastic...
63
contraction phase
 
external tension develops as muscle shortens
64
relaxation phase
 
loss of tension and return to resting length as calcium returns to SR
65
multiple motor unit summation
 
bringing more motor units into play/recruitment; i.e. lift a glass of milk versus a gallon...
66
twitch
 
low frequency (up to 10 stim./sec), produces an identical twitch response
67
treppe
 
moderate frequency (10-20 stim./sec); each twitch has time to recover but develops more tension...
68
temporal or wave summation
 
higher frequency stimulation (20-40/sec) generates gradually more strength of contraction;...
69
complete tetanus
 
maximum frequency (40-50/sec); muscle has no time to relax at all; twitches fuse into smooth,...
70
isometric muscle contraction
 
develops tension without changing length; important in postural muscle function and antagonistic...
71
isotonic muscle contraction
 
contraction with a change in length but no change in contraction
72
concentric isotonic contraction
 
tension while shortening
73
eccentric isotonic contraction
 
tension while lengthening
74
pathways of ATP synthesis (2)
 
anaerobic fermentation and aerobic respiration
75
anaerobic fermentation
 
ATP production limited; without oxygen, produces toxic lactic acid
76
aerobic respiration
 
more ATP produced; requires continuous oxygen supply, produces H2O and CO2
77
immediate energy needs
 
short, intense exercise (i.e. 100 m dash); oxygen need is supplied by myoglobin
78
Phosphagen system 
 
myokinase transfers Pi groups from ADP to make ATP; creatine kinase transfers Pi groups from...
79
short term energy needs
 
glycogen-lactic acid system takes over; produces ATP for 30-40 seconds of maximum activity...
80
long term energy
 
aerobic respiration needed for prolonged exercise; produces 36 ATP/glucose molecules; after...
81
fatigue
 
progressive weakness of muscles from prolonged use; ATP synthesis declines as glycogen is consumed;...
82
Endurance
 
ability to maintain high-intensity exercise >5 mins; determined by maximum oxygen uptake
83
maximum oxygen uptake (VO2 max)
 
proportional to body size, peaks at age 20, larger in trained athlete and males
84
carbohydrate loading
 
used by some athletes; packs glycogen into muscles; adds water at the same time (2.7g h20 with...
85
oxygen debt
 
heaving breathing after strenuous exercise; 
86
4 purposes oxygen debt used for
 
replaces oxygen reserves; replenishes phosphagen system, reconverts lactic acid to glucose...
87
slow oxidative, slow twitch fibers
 
more mitochondria, myoglobin, and capillaries; adapted for aerobic respiration and resistance...
88
fast glycolytic, fast twitch fibers
 
rich in enzymes for phosphagen and glycogen-lactic acid system; SR releases calcium quickly...
89
resistance training
 
weight lifting; stimulates cell enlargement due to synthesis of more myfilaments
90
endurance training
 
aerobic training; produces an increase in mitochondria, glycogen, and density of capillaries
91
strength of contraction
 
muscle size and fascicle arrangement; 3-4 kg/cm2 of cross sectional area; size of motor units...
92
smooth muscle
 
fuisform cells with one nucleus; no striations, sarcomeres, or z discs; thin filaments attach...
93
Multiunit smooth muscle
 
largest arteries, iris, pulmonary air passages; terminal nerve branches synapse on myocytes;...
94
single unit smooth muscle
 
most blood vessels and viscera as circular and longitudinal muscle layers; electrically coupled...
95
excitability
 
ability for cell to respond to a stimulus, especially the ability of nerve and muscle cells...
96
contractility
 
ability to shorten; amount of force that a contracting muscle fiber generates for a given stimulus
97
origin
 
where attached to bone, doesn't move
98
insertion
 
attached to joint, etc, and is moveable
99
prime mover
 
the muscle primarily responsible for a given joint action
100
antagonist
 
muscle that opposes the prime mover/agonist at a joint
101
fixator
 
 holding base solid : ie moving shoulder, fixator muscles allow scapula to stay in place;...
102
synergist
 
muscle that works with prime mover/agonist to assist


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