Musculoskeletal System Flashcards
(167 cards)
1
Q
responsible for all voluntary movements such as running as well as some involuntary movements such as breathing
A
skeletal muscle
2
Q
responsible for the beating action of the heart
A
cardiac muscle
3
Q
creates the movement in many hollow internal organs such as the gut and is under the control of the autonomic (involuntary) nervous system
A
smooth muscle
4
Q
All three muscle types use the same – mechanism
A
sliding filament contractile
5
Q
skeletal muscle cells called – are large and have many nuclei
A
muscle fibers
6
Q
muscle fibers form through the fusion of many individual embryonic muscle cells called
A
myoblasts
7
Q
a specific muscle such as the biceps is composed of 100s or 1000s of muscle fibers bundled together by –
A
connective tissue
8
Q
Muscle contraction is due to the interact between contractile proteins – and –
A
actin and myosin
9
Q
thin filaments
A
actin filaments
10
Q
thick filaments
A
myosin filaments
11
Q
true or false the actin and myosin filaments lie parallel to each other
A
true
12
Q
Each muscle fiber is packed with – which are bundles of thin actin and thick myosin filaments arranged in an orderly fashion
A
myofibrils
13
Q
each thick myosin filament is surrounded by
A
6 thin actin filaments
14
Q
each thin actin filament sits within a triangle of
A
3 thick myosin filaments
15
Q
the myofibril consists of repeating units of contraction called –
A
sarcomeres
16
Q
where there are only actin filaments the myofibril appears –
A
light
17
Q
where there are both actin and myosin filaments the myofibril appears
A
dark
18
Q
bundles of myosin filaments are held in a centered position within the sarcomere by a protein called
A
titin
19
Q
between the ends of the myosin bundles and Z lines, titin molecules are very
A
stretchable
20
Q
In a relaxed skeletal muscle, resistance to stretch is mostly due to the – of titin molecules
A
elasticity
21
Q
As the muscle contracrs, the sarcomeres – and the band pattern changes
A
shorten
22
Q
H zone and the I band become narrower and the Z lines move toward the A band when the muscle
A
contracts
23
Q
consists of 2 long polypeptide chains coiled together, each ending in a large myosin globular head
A
myosin molecule
24
Q
a myosin filament is made up of many myosin molecules arranged in parallel, with their heads projecting – at each end of the filament
A
sideways
25
consists of actin monomers polymerized into a long molecule that looks like two stands of pearls twisted together
actin filament
26
the myosin heads can bind to specific sites on actin forming -- between the myosin and actin filaments
cross-bridges
27
the myosin heads also have -- activity, when they are bound to actin they can bind and hydrolyze ATP
ATPase
28
the stiffening of muscles soon after death
rigor mortis
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ATP is needed to break the -- so when ATP production ceases with death, the muscles stiffens
actin-myosin bonds
30
Each myosin filaments has -- head(s) at both ends
many
31
muscle cells are -- because their plasma membranes can generate and conduct action potentials
excitable
32
in skeletal muscle fibers, AP are initiated by motor neurons arriving at a
neuromuscular junction
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the axon terminals of motor neurons are generally -- and form synapses with hundreds of muscle fibers
highly branched
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A motor neuron and al of the fibers with which it forms synapses constitute a --
motor unit
35
The fibers contract -- when its motor neuron fires
simultaneously
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Increase a muscle's strength of contraction by
increasing the firing rate of an individual motor neuron or recruit more motor neurons
37
The muscle fiber's plasma membrane is continuous with a system of T tubules that descend into its cytoplasm or
sarcoplasm
38
T tubules come very close to the ER of the muscle cell which is also called the
sarcoplasmic reticulum
39
When the muscle fiber is at rest, there is a -- concentration of Ca2+ in the sarcoplasmic reticulum and a lower concentration in the --
higher; sarcoplasm
40
spanning the space between the membranes of the T tubes and the membranes of the sarcoplasmic reticulum are --
two proteins
41
located in the T tubules membrane; it is voltage-sensitive and changes it conformation when an AP reaches it
dihydropyridine (DHP) receptor
42
located in the sarcoplasmic reticulum membrane; it is a Ca2+ channel
ryanodine receptor
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has three subunits that binds: actin, tropomyosin, and Ca2+
troponin
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When the muscle is at rest, the -- strands are positioned so that they block the sites on the actin filament where myosin heads can bind
tropomyosin
45
difference between cardiac and skeletal muscle
cardiac muscle cells are much smaller and only have on nucleus
46
cardiac muscle cells branch and the branches of adjoining cells interdigitate into a meshwork that is resistant to --
tearing
47
adding to the strength of cardiac muscles are -- that provide strong mechanical adhesions between adjacent cells
intercalated disc
48
protein structures that allow cytoplasmic continuity between cells in intercalated discs offer low-resistance pathways for ionic currents to flow between cells
gap junctions
49
AP initiated at one point in the heart spreads -- through a large mass of cardiac muscle
rapidly
50
-- and -- have low density of actin and myosin filaments but they initiate and coordinate the rhythmic contractions of the heart
pacemaker and conducting cells
51
pacemaker cells make the vertebrate heartbeat -- meaning it it generated by the heart itself
myogenic
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A heart removed from a vertebrate can continue to beat with no input from the nervous system; although input from the ANS modifies the -- of the pacemaker cells it is not essential for their continued rhythmic function
rate
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In cardiac muscle cells, the T-tubues are larger and the voltage-sensitive DHP proteins in the T tubules are-- and are not physically connected with the ryanodine receptors in the sarcoplasmic reticulum
Ca2+ channels
54
structurally the most simple muscle cells
smooth muscle cells
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smooth muscle cells are smaller than skeletal muscle cells and are usually -- and have 1 nucleus
long and spindle-shaped
56
Some smooth muscle tissue such as the wall of the digestive tract have cells that are arranged in sheets and individual cells in a sheet are in -- contact with one another through gap junctions as they are in cardiac muscle
electrical
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plasma membrane of smooth muscle cells are sensitive to
stretch
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Smooth muscle contracts after being stretched, and the harder it is stretched, the -- it contracts
harder
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changes in vascular smooth muscle-- are responsible for controlling the distribution of blood in the body
tone
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The neurotransmitters of the sympathetic and parasympathetic postganglionic cels alter the -- of smooth muscle cells
membrane potential
61
minimum unit of contraction
twitch
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the level of tension an entire muscle generates depends on the number of -- and the frequency at which --
number of motor units activated and the frequency at which the motor units fire
63
in muscles responsible for fine movements (fingers), a motor neuron may innervate - muscle fibers
one or a few
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in muscles that produces large forces (biceps) a motor neuron innervates -- muscle fibers
many
65
At the level of a muscle fiber, a single AP stimulates a -- twitch
single
66
If APs reaching the muscle fiber are adequately separated in time, each twitch is discrete,
all-or-none phenomenon
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Twitches sum at high levels of stimulation because the calcium pumps in the sarcoplasmic reticulum are not able to -- the Ca2+ ions from the sarcoplasm between AP
clear
68
eventually a stimulation frequency can be reached that results in continuous presence of Ca2+ in the sarcoplasm at high enough levels to cause continuous activation of the contractile machinery a condition called
tetanus
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The lack of ATP causes -- since the action of ATP is to break actin-myosin bonds
fatigue
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energy released from the hydrolysis of ATP "re-cocks" the -- allowing them to cycle through another power stroke
myosin heads
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Many muscles of the body maintain a low level of -- even when the body is at rest
tension
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comes from the activity of a small but chaining number of motor units in a muscle
muscle tone
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have high ATPase activity that can recycle their actin-myosin cross-bridges rapidly
fast-twitch fibers
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have lower ATPase activity that develop tension more slowly but can maintain it longer
slow-twitch fibers
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oxidative or red muscle because they contain myoglobin, have many mitochondria and well supplied with blood vessels
slow-twitch fiers
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slow-twitch fibers have substantial reserves of -- so they can maintain steady prolonged production of ATP as long as oxygen is available
fuel (glycogen and fat)
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glycolytic or white muscle have few mitochondria, little or no myoglobin, and fewer blood vessels
fast-twitch fibers
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good for short-term work that require maximum strength
fast-twitch fibers
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there are fast-twitch fibers that are somewhat oxidative and therefore -- in their properties between slow-twitch and fast glycolytic fibers
intermediate
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intermediate fibers can become more oxidative with -- training and more glycolytic with strength training
endurance
81
The most important determinant of you muscle fiber types is your
genetic heritage
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When a muscle is stretched and the sarcomeres are lengthened, there is less overlap between the actin and myosin filaments; therefore fewer -- can form and less -- produced
fewer cross-bridges; less force
83
if the -- are stretched too much, actin and myosin do not overlap and no force can be produced
sarcomeres
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anaerobic activities increase
strength
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aerobic activities increase
endurance
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-- is a function of the cross-sectional area of muscles: the more actin and myosin filaments in a muscle fiber, the more muscle fibers in a muscles, the more tension it can produce
strength
87
stress on a muscles does minor -- (soreness) but it also induces the formation of new actin and myosin filaments in existing muscle fibers
tissue damage
88
after serious muscle damage, new muscle fibers can also be produced from stem cells called -- in muscle
satellite cells
89
In general, the major effect of strength truing is to produced -- rather than more muscle fibers
bigger
90
aerobic exercise enhances muscles' -- involving greater number of mitochondria, increases in enzymes in energy use, and increases in density of capillaries that deliver oxygen to muscles
oxidative capacity
91
oxygen-bind protein that has a higher affinity for oxygen that hemoglobin
myoglobin
92
uses preformed ATP and creatine phosphate that are rapidly exhausted
immediate system = 10 kilocalories
93
metabolizes carbohydrates to lactate and pyruvate within a few seconds but lacks sustained efficient
glycolytic system
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metabolizes carbohydrates or fats all the way to water and carbon dioxide producing sustained efficiency but kicks in after about 1 minute
oxidative system
95
True or False: ATP is present in muscles in very small amounts
true
96
muscle fibers contain a storage compound called -- that stores energy in a phosphate bond which it can transfer to ADP
creatine phosphate (CP)
97
the rate at which oxidative metabolism can make ATP available to do work is -- than the the rate at which the other two systems can supply ATP
slower
98
the rate at which muscle glycogen is replenished depends on --
diet
99
high muscle glycogen replenishing
high-carbohydrate diet
100
low muscle glycogen replenishing
high-fat diet
101
intermediate muscle glycogen replenishing
mixed
102
Carbo-loading: for 3 to 5 days, athletes exercise at a level that -- muscle glycogen; then 2 or 3 days before the even they taper down their level of truing and eat a diet rich in complex carbs which results in -- in which the restoration of muscle glycogen stores "overshoots" and reaches above-normal levels
depletes; glycogen supercompensations
103
-- muscle has the greatest rate of cycling
insect
104
vertebrate (and most invertebrate) striated muscle is called -- because the cycling of the contractile mechanism is linked to the firing of the motor neurons
synchronous
105
the contractile cycling and the resulting frequency are not tied to the firing rate of the -- motor neurons
flight
106
rigid supports against which muscles pull to create directed movement
skeletal muscles
107
cnidarians, annelids, and other soft-bodied invertebrates have -- consisting of a volume of fluid enclosed in a body cavity surrounded by muscle
hydrostatic skeletons
108
constriction of circular muscles -- and -- the segments, pushing them forward
narrows and elongates
109
constriction of longitudinal segments -- the segments, pulling the trailing segments forward
shortens and bulges outward
110
bulging, shortened segments serves as -- as long, narrow segments project forward
anchors
111
-- help the widest part of the body to hold firm against substratum preventing backward sliding
bristles
112
hardened, rigid outer surface to which muscles can be attached
exoskeleton
113
the simplest example of the exoskeleton is the -- of a mollusk
shell
114
some marine mollusks (clams) have shells composed of protein strengthened by crystals of --
calcium carbonate (rock-hard material)
115
shells of -- mollusks like snails generally lack the hard mineral component and are much lighter
land
116
the most complex exoskeletons are found among --
arthropods
117
an exoskeleton or -- covers all the outer surfaces of the arthropod's body and all its appendages
cuticle
118
the cuticle contains stiffening materials everywhere except at -- where flexibility must be retained
joints
119
a drawback of the rigid arthropod exoskeleton is that it cannot
expand
120
If an arthropod becomes too larger it must -- or shed its exoskeleton forming a new, larger one
molt
121
a molting animals is -- because the new exoskeleton takes time to harden
vulnerable
122
the vertebrate endoskeleton consist of -- and --
cartilage and bone
123
an advantage of endoskeletons over exoskeletons of arthropods is that -- in the body can grow without the animal shedding its skeleton
bones
124
the human skeleton consists of -- bones
206
125
axial skeleton
skull, vertebral column, sternum, and ribs
126
appendicular skeleton
pectoral and pelvic girdle, arms, legs, had, feet
127
produce an extracellular matrix that is tough, rubbery mixture of polysaccharides and proteins (mainly fibrous collagen)
cartilage cels
128
collagen fibers run in all directions like reinforcing cords through the gel-like matrix and give it the well-known -- and -- or "gristle"
strength and resiliency
129
found in parts of the endoskeleton where both stiffness and resiliency are required (joints)
cartilage
130
supportive tissue in stiff but flexible structures like larynx, nose, and ear pinnae
cartilage
131
sharks and rays are called -- because their skeletons are composed entirely of cartilage
cartilaginous fishes
132
contains collagen fibers but gets its rigidity and hardness from an extracellular matrix of insoluble calcium phosphate crystals
bone
133
lay day down new matrix material on bone surfaces in layers; in long bones these layers form concentric tubes parallel to the long axis of the bone
osteoblasts
134
osteoblasts gradually become enclosed within bone at which point they cease laying down matrix but continue to exist within small lacunae
osteocytes
135
despite the vast amounts of matrix between them, osteocytes communicate about -- through long cellular extensions that run through tiny channels in the bone
controlling activities of cells that are laying down or removing bone
136
cells that remove bone; derived from the same cell linear that produces white blood cells
osteoclasts
137
because of the positive effects of physical stress on bone deposition, weight-bearing exercise is effecting in preventing an treating the loss o bone density and strength
osteoporosis
138
includes eating disorders, cessation of menstrual cycling, and osteoporosis
female athlete triad
139
forms on a scaffold of connective tissue membrane
membranous bone
140
forms first as a cartilaginous structure resembling the future mature bone then gradually ossifies to bone
cartilage bone
141
outer bones of skull are -- bone
membranous
142
bones of the limbs are
cartilage bones
143
the long bones of legs and arms ossify first at the -- and later at the --
first at the center (shaft) and later at each end
144
growth can continue until the areas of -- join
ossification
145
the soft spot on the top of a baby's head is the point at which the skull bone have not yet joined
fontanelle
146
solid and hard bond
compact
147
having numerous internal cavities that make it appear spongy although it is rigid
cancellous
148
the shafts of the long bones of limbs are cylinders of -- surrounding central cavities that contain the bone marrow
compact bone
149
where the cellular elements of the blood are made
bone marrow
150
the ends of long bones are -- bone
cancellous
151
most of the compact bone in mammals is called --
Haversian bone
152
each Haversian system is a set of thin, concentric bony -- between which are the osteocytes in their lacunae
cylinders
153
A narrow canal containing -- runs through the center of each Haversian system
blood vessels and nerves
154
adjacent Haversian systems are separated by boundaries called --
glue lines
155
Haversian bone is resistant to fracturing because cracks tend to -- at glue line
stop
156
-- are sites of elongation between the ossified regions
epiphyseal plates
157
muscles and bones work together around -- where two or more bones come together
joints
158
true or false: muscles can exert force in only one direction
true
159
muscles create movements around joints by working in -- when one muscle contrast the other relaxes
antagonistic pairs
160
when both muscles contract the joint becomes -- (posture)
rigid
161
muscle that bends or flexes the joint
flexor
162
the muscles that straightens or extends the joint
extensor
163
A lever has an -- arm and a -- arm that work around a fulcrum (pivot)
effort arm and load arm
164
2 Load arm: 1 effort arm generate -- over a small distance
much force
165
5 Load arm: 1 effort arm moves low weights long distances with --
speed
166
an example of a lever system designed for applying maximum force is (effort arm is long relative to the load arm)
human jaw
167
an example of a lever system designed of speed is the (effort arm is short relative to the load arm)
human leg
