Exam #3 Chapter 9 Muscular system (histology & physiology) part 1 Flashcards

1
Q

though skeletal muscle fibers don’t divide what DO they do and what is that?

A

hypertrophy- increase in size

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2
Q

what are myofibrils composed of?

A

protein fibers (myofilaments)

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3
Q

where is smooth muscle located?

A

walls of hollow organs, blood vessels, eyes, glands and skin

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4
Q

what is the cell shape of smooth muscle?

A

spindle shaped

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5
Q

what is a neuromuscular junction?

A

a few enlarged presynaptic (axon terminals separated from the fiber by a small synaptic cleft

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6
Q

what do nerves do in a muscle fiber?

A

enter a muscle, branch and contract each muscle fiber near the middle.

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7
Q

what does the myosin heads do?

A

they bind the actin active site and are an ATPase enzyme

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8
Q

what is the endonysium?

A

a delicate structure that surrounds each muscle fiber

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9
Q

do skeletal muscles have special cell-to-cell attachments and if so what are they?

A

no

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10
Q

if you cut a nerve from skeletal muscle what will happen?

A

the muscle will never contract again

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11
Q

what type of tissue does skeletal muscle contain?

A

connective tissue

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12
Q

what is contractility?

A

the ability for the muscle to shorten forcefully or contract?

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13
Q

what is the knowledge of skeletal muscle fiber structure required to understand?

A

the muscle contraction

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14
Q

where is the muscular fascia located/

A

superficial to the epimysium

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15
Q

are any of the muscle tissues capable of spontaneous contraction?

A

yes, cardiac muscle and some smooth muscle tissue

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16
Q

what is the plasma membrane of a fiber called?

A

the sarcolemma

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17
Q

what are T Tubules continous with?

A

the sarcolemma

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18
Q

what are the tube-lie extensions of the sarcolemma into the cytoplasm of a fiber called?

A

transverse (T) tubules

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19
Q

what is the sarcomere?

A

the functional unit of a muscle (the smallest structure that can contract)

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20
Q

what type of nucleus does smooth muscle have and where?

A

single, centrally located

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21
Q

what are Z disk composed of?

A

proteins to which the thin filaments attach in an ordered way

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22
Q

what is extensibility?

A

when a muscle can be stretched beyond its normal resting length and still be able to contract.

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23
Q

what is another word for nerves?

A

somatic motor neuron axons

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24
Q

in muscle fibers what is the extensive smooth endoplasmic retiuculum called?

A

sarcoplasmic reticulum

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25
Q

what is the cell shape of skeletal muscle?

A

very long and cylindrical

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26
Q

which muscle tissues are voluntary and which are involuntary?

A

skeletal is both voluntary and involuntary (reflexes) and smooth and cardiac are involuntary

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27
Q

what are some function of smooth muscle? (6) (MERCCM)

A

1) moving food through the digestive system
2) emptying the urinary bladder
3) regulating blood vessel diameter
4) changing pupil size
5) contracting many gland ducts
6) moving hair

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28
Q

besides the mitochondria and glycogen granules what else does sarcoplasm contain?

A

many rod-like organelles called myofibrils

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29
Q

how many cells is a muscle fiber?

A

one cell

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30
Q

what do skeletal muscle look like?

A

1) long
2) cylindrical
3) multinucleate
4) striated cells

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31
Q

what is an example of contractility?

A

lifting a textbook requires certain muscles to contract.

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32
Q

which muscle tissue enables us to breath?

A

skeletal

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33
Q

in muscle fibers what is the postsynaptic membrane?

A

the muscle fiber sarcolemma

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34
Q

what do skeletal muscle fibers develop from?

A

the fusion of many myoblasts

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35
Q

what are myosin molecules composed of?

A

2 myosin protein chains

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36
Q

does cardiac muscle tissue have special cell-to-cell attachments and if so what are they?

A

yes, intercalated disks join cells to one another

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37
Q

what does thin filaments also contain besides titin?

A

two strands of tropomyosin molecules

38
Q

what is the cell shape of cardiac muscle?

A

cylindrical and branched

39
Q

which muscle tissue moves substances?

A

all of them

40
Q

what is the muscular fascia?

A

separates individual muscles or group of muscles

41
Q

what else is in the sacrcomere ?

A

other proteins to regulate the interaction between thick and thin filaments and others to stabilize the ordered structure of the sarcomere

42
Q

what type of nucleus does skeletal muscle have and where?

A

multiple nuclei (peripherally located)

43
Q

what does the rest of the A band contain?

A

thick and thin filaments

44
Q

how do muscles function?

A

by forcefully shortening

45
Q

how are the myofilaments organized?

A

into a highly organized and repeating structures called sarcomeres

46
Q

besides titin and tropomyosin what else does thin filaments contain?

A

troponin molecules

47
Q

what is the cytoplasm in a muscle cell called?

A

sarcoplasm

48
Q

what are the thick myofilaments composed of?

A

mostly myosin

49
Q

which muscle tissue produces body movement?

A

skeletal

50
Q

what does titin do?

A

it keeps the ends of the thick filaments in position

51
Q

what does the presynaptic terminals contain?

A

vessicles with the neurotransmitter acetylcholine (ACh)

52
Q

when an action potential comes down the axon what does the axon terminals release?

A

aCh

53
Q

what do Z lines (disks) do?

A

separate individual sarcomeres (boxcars filaments attach in an ordered way)

54
Q

what is the function of skeletal muscle

A

body movement

55
Q

what is the sarcoplasmic reticulum?

A

a compartment for calcium storage

56
Q

what are the epimysium, perimysium and endomysium made of?

A

connective tissue

57
Q

what is the perimysium?

A

surrounds a group of fiber muscles (fascicle) and is fibrous

58
Q

where in the sarcomere are the thick filaments located?

A

in the center and positioned by proteins of the M line in an ordered array

59
Q

what do all muscle tissues display? (4) (ECEE)

A

1) electrical excitability
2) contractility
3) extensibility
4) elasticity

60
Q

what is elasticity?

A

the ability of a muscle to spring back to its original resting length after it has been stretched.

61
Q

what functions does muscle tissue have? (5) (BSEGM)

A

1) body movements
2) stabilizes our body position
3) enables us to breath and to communicate
4) generates heat
5) moves substances in our body

62
Q

what type of connective tissue is the epimysium?

A

dense irregular collagenous connective tissue

63
Q

what does motor neuron axons carry?

A

action potential to muscle fibers at the neuromuscular junction to produce contraction

64
Q

what are the 3 subunits of troponin do??

A

bind G actin, tropomyosin and calcium

65
Q

what is excitablility?

A

the capacity of a muscle to respond to an electrical stimulus.

66
Q

where is the H Zone located in the sarcomere?

A

in the center

67
Q

what is caused when the ACh diffuses across the synaptic cleft and binds with ligand-gated channels?

A

causes an action potention in the sacrolemma

68
Q

what do muscle only do when contracting?

A

shorten, they never lengthen

69
Q

does the thin filaments reach the M line?

A

only part of the way

70
Q

what are the thin myofilaments composed of?

A

mostly actin

71
Q

what does the sarcoplasm contain?

A

the mitochondria and glycogen granules

72
Q

what type of nucleus does cardiac muscle have and where?

A

single, centrally located

73
Q

where does the light or I band extend from?

A

the ends of the thick filaments in one or more sarcomere to the ends of the thick filaments in the adjacent sarcomere (z disk in middle)

74
Q

which muscle tissues are striated?

A

skeletal and cardiac

75
Q

what does the thin and thick filaments produce?

A

they are aligned producing alternating dark and light bands (striations)

76
Q

what is the entire skeletal muscle surrounded by?

A

the epimysium

77
Q

what is the part of the sarcomere that contains the thick filament?

A

dark or A band

78
Q

what does skeletal muscle fibers NOT do?

A

divide

79
Q

what does the rod-like portion of mysoin form?

A

the thick filament with heads facing out

80
Q

which muscle tissue stabilizes our body position (posture)?

A

skeletal

81
Q

what do the 2 myosin protein chains composed from mysoin look like?

A

they have a rod-like portion and a hinged head

82
Q

what does the H zone only contain?

A

thick filaments

83
Q

what are thin filaments composed of?

A

two strands of G actin monomers

84
Q

what does troponin and tropomyosin regulate?

A

the interaction between mysoin and actin

85
Q

what does the ACh do when it’s released by the axon terminals?

A

it diffuses across the synaptic cleft, binds to the ligand-gated channels

86
Q

what do blood vessels do in a muscle fiber?

A

branch and form capillaries around each fiber

87
Q

which muscle tissue generates heat?

A

all of them

88
Q

what are thick filaments composed of?

A

myosin molecules

89
Q

does smooth muscle tissue have special cell-to-cell attachments and if so what are they?

A

yes, gap junctions join SOME visceral smooth muscle cells together

90
Q

what does each G actin monomer each have?

A

an active site to which myosin binds