Musculoskeletal System Flashcards Preview

Life Science 2 > Musculoskeletal System > Flashcards

Flashcards in Musculoskeletal System Deck (167):
1

responsible for all voluntary movements such as running as well as some involuntary movements such as breathing

skeletal muscle

2

responsible for the beating action of the heart

cardiac muscle

3

creates the movement in many hollow internal organs such as the gut and is under the control of the autonomic (involuntary) nervous system

smooth muscle

4

All three muscle types use the same -- mechanism

sliding filament contractile

5

skeletal muscle cells called -- are large and have many nuclei

muscle fibers

6

muscle fibers form through the fusion of many individual embryonic muscle cells called

myoblasts

7

a specific muscle such as the biceps is composed of 100s or 1000s of muscle fibers bundled together by --

connective tissue

8

Muscle contraction is due to the interact between contractile proteins -- and --

actin and myosin

9

thin filaments

actin filaments

10

thick filaments

myosin filaments

11

true or false the actin and myosin filaments lie parallel to each other

true

12

Each muscle fiber is packed with -- which are bundles of thin actin and thick myosin filaments arranged in an orderly fashion

myofibrils

13

each thick myosin filament is surrounded by

6 thin actin filaments

14

each thin actin filament sits within a triangle of

3 thick myosin filaments

15

the myofibril consists of repeating units of contraction called --

sarcomeres

16

where there are only actin filaments the myofibril appears --

light

17

where there are both actin and myosin filaments the myofibril appears

dark

18

bundles of myosin filaments are held in a centered position within the sarcomere by a protein called

titin

19

between the ends of the myosin bundles and Z lines, titin molecules are very

stretchable

20

In a relaxed skeletal muscle, resistance to stretch is mostly due to the -- of titin molecules

elasticity

21

As the muscle contracrs, the sarcomeres -- and the band pattern changes

shorten

22

H zone and the I band become narrower and the Z lines move toward the A band when the muscle

contracts

23

consists of 2 long polypeptide chains coiled together, each ending in a large myosin globular head

myosin molecule

24

a myosin filament is made up of many myosin molecules arranged in parallel, with their heads projecting -- at each end of the filament

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

29

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

33

the axon terminals of motor neurons are generally -- and form synapses with hundreds of muscle fibers

highly branched

34

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

36

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

43

has three subunits that binds: actin, tropomyosin, and Ca2+

troponin

44

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

52

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

53

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

55

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

57

plasma membrane of smooth muscle cells are sensitive to

stretch

58

Smooth muscle contracts after being stretched, and the harder it is stretched, the -- it contracts

harder

59

changes in vascular smooth muscle-- are responsible for controlling the distribution of blood in the body

tone

60

The neurotransmitters of the sympathetic and parasympathetic postganglionic cels alter the -- of smooth muscle cells

membrane potential

61

minimum unit of contraction

twitch

62

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

64

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

67

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

69

The lack of ATP causes -- since the action of ATP is to break actin-myosin bonds

fatigue

70

energy released from the hydrolysis of ATP "re-cocks" the -- allowing them to cycle through another power stroke

myosin heads

71

Many muscles of the body maintain a low level of -- even when the body is at rest

tension

72

comes from the activity of a small but chaining number of motor units in a muscle

muscle tone

73

have high ATPase activity that can recycle their actin-myosin cross-bridges rapidly

fast-twitch fibers

74

have lower ATPase activity that develop tension more slowly but can maintain it longer

slow-twitch fibers

75

oxidative or red muscle because they contain myoglobin, have many mitochondria and well supplied with blood vessels

slow-twitch fiers

76

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)

77

glycolytic or white muscle have few mitochondria, little or no myoglobin, and fewer blood vessels

fast-twitch fibers

78

good for short-term work that require maximum strength

fast-twitch fibers

79

there are fast-twitch fibers that are somewhat oxidative and therefore -- in their properties between slow-twitch and fast glycolytic fibers

intermediate

80

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

82

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

84

anaerobic activities increase

strength

85

aerobic activities increase

endurance

86

-- 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

94

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